LZX – invented by Jonathan Forbes and Tomi Poutanen, given to Microsoft when Forbes joined the company
A CAB archive can reserve empty spaces in the archive as well as for each file in the archive, for some application-specific uses like digital signatures or arbitrary data. CAB format is used by a variety of Microsoft installation technologies including Windows Installer, Setup API, Device Installer and AdvPack (used by Internet Explorer to install ActiveX components). CAB files are also often associated with self-extracting programs where the executable program extracts the associated CAB file. CAB files are also sometimes embedded into other files. For example, MSI files usually included one or more embedded CAB files.
A CAB archive can contain up to 65535 CAB-folders, (not to be confused with file system folders,) each can contain up to 65535 files. A CAB-folder is a nameless collection of files each with its own path. Due to this structure, it is not possible to store empty folders in CAB archives.
The following shows an example a CAB file structure, demonstrating the relationship between CAB-folders and files:
How paths should be handled is not specified in the CAB file format, leaving it to the software implementation.
Some affix file paths to filenames only, as if all files in a CAB archive are in a single folder. IExpress works this way, as does Microsoft Windows Explorer, which can open CAB archives as a folder.
Some can store the paths, and upon extraction, create folders as necessary. CABARC.EXE and EXTRACT.EXE (tools from Microsoft Cabinet SDK ) as well as lcab and cabextract (third-party open-source tools) work this way.
EXPAND.EXE, only since version 6 (which is included from Windows Vista to above) can extract files to their paths. The previous versions don't do it.
The .cabfilename extension is also used by other installer programs (e.g. InstallShield) for their own proprietary archiving formats. InstallShield uses zlib for compression (see Deflate), but their headers are not the same as for Microsoft CAB files so they are incompatible and cannot be manipulated or edited with the programs that are made for standard Cabinet format. Specialized third-party utilities, such as Unshield, can extract this specific proprietary format.
Microsoft Publisher has a "Pack and Go" feature that bundles a publisher document, together with all external links, into a CAB file with a .PUZ extension. These files are meant to be activated with a companion .EXE file which is distributed along with the .PUZ file. These files may be renamed and activated with any CAB file extraction program.