Proprietary hardware is
computer hardware
Computer hardware includes the physical parts of a computer, such as the computer case, case, central processing unit (CPU), Computer monitor, monitor, Computer mouse, mouse, Computer keyboard, keyboard, computer data storage, graphics card, so ...

whose
interface
Interface or interfacing may refer to:
Academic journals
* Interface (journal), ''Interface'' (journal), by the Electrochemical Society
* ''Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Lin ...
is controlled by the
proprietor
Ownership is the state or fact of exclusive rights and control over property, which may be any asset, including an object, land or real estate, intellectual property, or until the nineteenth century, slaves, human beings. Ownership involves multi ...
, often under
patent
A patent is a type of intellectual property
Intellectual property (IP) is a category of property
Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depe ...

or
trade-secret protection.
Historically, most early computer hardware was designed as proprietary until the 1980s, when
IBM PC
The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first computer released in the IBM PC model line and the basis for the IBM PC compatible
IBM PC compatible computers are similar to the original IBM PC
The IBM ...
changed this paradigm. Earlier, in the 1970s, many vendors tried to challenge IBM's monopoly in the
mainframe computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as census, censuses, industry and consumer statistics, ent ...
market by
reverse engineering
Reverse engineering (also known as backwards engineering or back engineering) is a process or method through the application of which one attempts to understand through deductive reasoning
Deductive reasoning, also deductive logic, is the process ...

and producing hardware components electrically compatible with expensive equipment and (usually) able to run the same software. Those vendors were nicknamed ''
plug compatible
Plug compatible refers to "hardware that is designed to perform exactly like another vendor's product." The term PCM was originally applied to manufacturers who made replacements for IBM peripherals. Later this term was used to refer to IBM-compatib ...
manufacturers'' (PCMs).
See also
*