CAB (file format)
| CAB | |
|---|---|
| File extension : |
.cab
|
| MIME type : | application / vnd.ms-cab-compressed |
| Magic number : |
4D53.4346 hex MSCF ( ASCII-C notation ) |
| Developed by: | Microsoft |
| Type: | Data compression |
| Container for: | any files |
The file format CAB (abbr. For English cabinet , filing cabinet ' ) is a format for compressed archive files.
description
The archive files usually have the filename extension .cab and the MIME type application/vnd.ms-cab-compressed or application/x-cab-compressed.
The CAB format enables several files to be saved in one archive file, whereby path information can also be saved and the files can be extracted again together or individually. It is also possible to divide the archive over several files (for example, to divide large files into pieces that each fit on one data carrier).
In the CAB format, the files are compressed individually or in groups. Individually compressed files are advantageous if you only want to extract individual files later, since only these then have to be decompressed. When compressing in groups, redundancies between the files can be taken into account during compression so that the archive file becomes smaller. When accessing a file, however, the whole group always has to be decompressed, so that this method should only be used if you usually want to extract the whole group anyway.
The CAB file format uses three methods of data compression :
- 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 . The algorithm fell to Microsoft when Forbes started working at Microsoft.
The command line programs EXPAND and EXTRACT are available under Windows for unpacking CAB files.
For use on Windows Mobile , CAB files can also be extended with an XML file of instructions. The package management of Windows Mobile can such a packed software then install and set up (eg. As Start menu entries to create or change the default browser) and remove if necessary. It is therefore comparable to the MSI file format under Windows. Such installable CAB files are usually created with Visual Studio .
history
CAB files were originally introduced by Microsoft to compress software that was shipped on diskettes and to reduce the number of diskettes required. Today they are mostly used for software on CDs or downloads from the Internet, especially Microsoft software or software whose installer comes from Microsoft. Even Windows patches are often distributed as a self-extracting CAB file.
File extension for other files
The CAB file extension is also used by many installers ( InstallShield and others), although they do not use the same file format.
See also
Web links
- cabextract is free software to extract CAB files on UNIX.
- libmspack is a portable library under LGPL license for creating and extracting CAB files and other Microsoft formats.