Proprietary hardware is hardware on which a vendor purposely places compatibility restrictions, in order to maintain a vendor lock-in.

For example, a vendor installs a proprietary Accelerated Graphics Port (AGP) on its motherboards, which is compatible only with same vendor's graphics card.

Historically, most early computer hardware was designed as proprietary until the 1980s, when IBM PC changed this paradigm. Earlier, in 1970s, many vendors tried to challenge IBM's monopoly in the mainframe computer market by reverse engineering and producing hardware components electrically compatible with expensive equipment and (usually) able to run the same software. Those vendors were nicknamed plug compatible manufacturers (PCMs).

The most notable present day proprietary computing company is Apple with their line of Macs.

See also

• Vendor lock-in
• Micro Channel architecture, a commonly cited historical example of proprietary hardware