In Microsoft program development, a cabinet is a single file created to hold a number of compressed files. A related set of cabinet files can be contained in a folder. During installation of a program, the compressed files in a cabinet are decompressed and copied to an appropriate directory for the user. A cabinet file usually has the file name suffix of ".cab".
Microsoft uses cabinet files in distributing its own products, such as PowerPoint, Microsoft Office for Windows, and Microsoft Money. Cabinet files save space and time during software distribution. They are decompressed during installation. Large files can be compressed and included in more than one cabinet file, each of which logically points to the next file, with all contained in a logical folder.
Development accountability for cabinet files is ensured by providing a signed digital certificate with the cabinet file. One "signature" covers all the files in a cabinet file. Cabinet files are created using Lempel-Ziv compression.