Cabinet (file format)

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4D53.4346 hex MSCF ( ASCII C notation )

The file format CAB (abbreviation for English " cabinet", German " filing cabinet " ) is a format for compressed archive files.


The archive files usually carry the file name extension. Cab and have the MIME type application / -cab -compressed or application / x -cab -compressed.

The CAB format allows you to store multiple files in an archive file, and path information can be stored as well, and the files together or individually to extract again. It is also possible to distribute the archive into multiple files ( for example, to divide large files into pieces that each fit on one disk).

In the CAB format the files are compressed individually or in groups. Individually compressed files are beneficial when you want to extract only individual files later because only then they must be decompressed. In compression in groups redundancies between the files can be omitted at the time, so that the archive file is smaller. It must then when accessing a file but getting the whole group to be decompressed, so this method should be used only if one anyway mostly trying to extract the whole group.

The CAB file format used three methods of data compression:

  • Deflate, invented by Phil Katz, the author of the zip file format
  • Quantum, licensed from David Stafford, author of Quantum Archiver
  • LZX, invented by Jonathan Forbes and Tomi Poutanen. The algorithm was to Microsoft when Forbes started working at Microsoft.

For unpack CAB files are under Windows command line programs and EXPAND EXTRACT available.

For use on Windows Mobile can also be extended by an XML file with instructions CAB files. The package management on Windows Mobile can then install the software and set packed in such a way (for example, create start menu entries, or change the default browser ) and uninstall if necessary. It is thus comparable with the MSI file format for Windows. Be created such installable CAB files usually with Visual Studio.


Cab files were originally introduced by Microsoft to compress on diskettes supplied software and reduce the number of required diskettes. Today they are mainly used for software on CDs or downloads from the Internet, especially with Microsoft software or software whose installer came from Microsoft. Even Windows patches are often distributed as self-extracting CAB file.

File extension for other files

The CAB file extension is also used by many installers ( InstallShield and others), even though they do not use the same file format.