What is a Cab file ?

I wanna ask what is cab file format? and how can I store the files in the cab format? Can anybody please provide the useful details about the same.....

thanks

Cab files are compressed archives. The term "Archive" in this context means that the file may contain one or more files, or even folders, much like folders on your hard disk. "Compressed" means that mathematical techniques have been used to reduce the space needed to store the files, so that the size of the archive may be much smaller than the size of the files it contains. There are many different compression techniques in use today. "Cab" is the name given to a compression algorithm originally developed by Microsoft for packaging groups of related files in a space-saving way. It's short for "Cabinet", which quite neatly describes a container for a file or group of files. Cabinet files are mostly used by Microsoft and other software installers, so Cab files usually contain software components.

In short, Cab files are a space-saving way of storing single files or groups of related files.

Files in a Cab archive will decompress to exactly their original state. This is called "lossless compression." The compression methods used with JPG image files or MP3 music files are called "lossy compression" because some of the quality of the original image or sound is lost during the compression process.

Cab files are used because they take up less space to store, and take less time to send or download. They are also a very convenient way to package and send groups of related files. However, you can't run a program directly from a Cab file. The files must be extracted or unzipped from the archive before they can be used.

CAB is short for Cabinet, and a CAB file is a group of files which are downloaded together into one single compressed file to conserve disk space. CAB files are generally used to distribute software - many Microsoft product files are stored this way.
In order to access the individual files you need to extract them. If you're using Windows 95 or 98 you need a special utility to do this called Alpha Zip.

In computing, CAB is the Microsoft Windows native compressed archive format. It supports compression and digital signing, and is used in a variety of Microsoft installation engines: Setup API, Device Installer, AdvPack (for the installation of ActiveX components from Internet Explorer) and Windows Installer.

It was originally called Diamond. Its .CAB file extension and overall file format name comes from word cabinet, internally used by Microsoft tools dealing with CAB files to reference such files.

The CAB file format allows for three data compression methods:

• DEFLATE, invented by Phil Katz, the author of the ZIP file format.
• Quantum, licensed from David Stafford, the author of the Quantum archiver.
• LZX, invented by Jonathan Forbes and Tomi Poutanen, given to Microsoft when Jonathan joined the company.

Some useful points to remember -

• CAB files contain one or more files and can also reserve empty space in the file header for some specific uses like placing digital signatures or arbitrary data.
• CAB files are also often attached to self-extracting programs where the executable program extracts the attached CAB file.
• CAB files are sometimes embedded into other files. For example, MSI files usually contain one or more embedded CAB files. You can easily recognize Microsoft CAB files since all CAB files have a specific marker at the beginning of the file, identifying the file format. For Microsoft CAB files this marker is a four-letter tag MSCF.