User:Shivaraj naidu/sandbox

Scalpel is a free and open source file carver data recovery software tool designed to recover lost files from digital camera memory (CompactFlash, Memory Stick, Secure Digital, SmartMedia, Microdrive, MMC, USB flash drives, etc.), hard disks and CD-ROMs. It recovers most common photo formats, including JPEG, and also recovers audio files including MP3, document formats such as OpenDocument, Microsoft Office, PDF and HTML, and archive formats including ZIP.

PhotoRec is compatible with:
 * Microsoft Windows: NT4, 2000, XP, 2003, 2008, Vista, Windows 7
 * Linux

For example, PhotoRec identifies a JPEG file when a block begins with:
 * Start Of Image + APP0: 0xff, 0xd8, 0xff, 0xe0
 * Start Of Image + APP1: 0xff, 0xd8, 0xff, 0xe1
 * or Start Of Image + Comment: 0xff, 0xd8, 0xff, 0xfe

If PhotoRec has already started to recover a file, it stops its recovery, checks the consistency of the file when possible and starts to save the new file (which it determined from the signature it found).

If the data is not fragmented, the recovered file should be either identical; or possibly larger than the original file, in size. In some cases, PhotoRec can learn the original filesize from the file header, so the recovered file is truncated to the correct size. If, however, the recovered file ends up being smaller than its header specifies, it is discarded. Some files, such as *.MP3 types, are data streams. In this case, PhotoRec parses the recovered data, then stops the recovery when the stream ends.

When a file is recovered successfully, PhotoRec checks the previous data blocks to see if a file signature was found but the file was not able to be successfully recovered (i.e., the file was too small), and it tries again. This way, some fragmented files can be successfully recovered.

Distribution
PhotoRec and TestDisk are shipped together. They can be downloaded from CGSecurity website. These utilities can be found on various Linux Live CDs: They are also packaged for numerous Linux based distributions:
 * GParted Live CD
 * Parted Magic
 * Slax-LFI, a Slax-derived distribution
 * SystemRescueCD
 * Trinity Rescue Kit
 * Ubuntu Rescue Remix, an Ubuntu derivation
 * ALT Linux
 * ArchLinux Extra Repository
 * Debian contrib
 * Fedora Extras
 * Red Hat Epel
 * FreeBSD ports
 * Gentoo and Gentoo Portage
 * Mandriva contrib
 * PLD Linux Distribution
 * Source Mage GNU/Linux
 * Ubuntu