Editing Coprocessor (section)

==History==
To make the best use of [[mainframe computer]] processor time, input/output tasks were delegated to separate systems called [[Channel I/O]]. The mainframe would not require any I/O processing at all, instead would just set parameters for an input or output operation and then signal the channel processor to carry out the whole of the operation. By dedicating relatively simple sub-processors to handle time-consuming I/O formatting and processing, overall system performance was improved.

Coprocessors for floating-point arithmetic first appeared in [[desktop computer]]s in the 1970s and became common throughout the 1980s and into the early 1990s.  Early 8-bit and 16-bit processors used software to carry out [[floating-point]] arithmetic operations. Where a coprocessor was supported, floating-point calculations could be carried out many times faster. Math coprocessors were popular purchases for users of [[computer-aided design]] (CAD) software and scientific and engineering calculations.  Some floating-point units, such as the [[Intel_8231/8232|AMD 9511]], [[Intel 8231/8232]] and [[Weitek]] FPUs were treated as peripheral devices, while others such as the [[Intel 8087]], [[Motorola 68881]] and [[National 32081]] were more closely integrated with the CPU.

Another form of coprocessor was a video display coprocessor, as used in the [[Atari 8-bit computers]], [[TI-99/4A]], and [[MSX]] home computers, which were called "[[Video Display Controller]]s". The [[Amiga]] [[Original Amiga chipset|custom chipset]] includes such a unit known as the [[Original Amiga chipset#Copper|Copper]], as well as a [[blitter]] for accelerating [[bitmap]] manipulation in memory.

As microprocessors developed, the cost of integrating the floating-point arithmetic functions into the processor declined.  High processor speeds also made a closely integrated coprocessor difficult to implement. Separately packaged mathematics coprocessors are now uncommon in desktop computers.  The demand for a [[graphics processing unit|dedicated graphics coprocessor]] has grown, however, particularly due to the increasing demand for realistic [[3D graphics]] in [[video game|computer games]].