Clone (computing)

From Wikipedia, the free encyclopedia

In computing, a clone is a hardware or software system that is designed to mimic another system. Compatibility with the original system is usually the explicit purpose of cloning hardware or low-level software such as operating systems. Application software can be cloned simply by providing similar functionality (all word processors have the same basic purpose), but may also be designed to support specific file formats (e.g., OpenOffice.org is intended to supplant Microsoft Office).

Clones are created for various reasons, including competition, standardization, and availability across platforms.

[edit] Hardware

When IBM announced the IBM PC in 1981, other companies such as Compaq decided to offer clones of the PC as a legal reimplementation from the PC's documentation or reverse engineering. Because most of the components, except the PC's BIOS, were publicly available, all Compaq had to do was reverse-engineer the BIOS. The result was a machine with better value than the archetypes that the machines resembled. The use of the term "PC clone" to describe IBM PC compatible computers fell out of use in the 1990s; the class of machines it now describes are simply called PCs, Intel machines, or even Wintel machines.

While the term has fallen mostly into commercial disuse, the term clone for PCs still applies to a PC made to entry-level or above standard (at the time it was made) which bears no commercial branding (e.g., Acer, IBM, HP, Dell). This includes, but is not limited to, PCs assembled by home users or Corporate IT Departments. (See also White box (computer hardware).)

Distinct from clones are home computer remakes. Clones are made during a product's initial commercial run, intentionally competing with the original. Remakes are revivals of old, obsolete, or discontinued models.

[edit] Software

Software can be cloned by reverse engineering or legal reimplementation from documentation or other sources, or by observing a program's appearance and behavior. The reasons for cloning may include circumventing undesirable licensing fees or acquiring knowledge about the features of the system. In the United States, the case of Lotus v. Borland allows programmers to clone the public functionality of a program without infringing its copyright.