A pple Computer Inc. was recently granted a United States Patent for a "Hardware graphics accelerator having access to multiple types of memory including cached memory." The patent, which was filed May 1, 1995 and granted April 16, 2002, goes into great detail about the device but also gives a general insight into the possible application. From the USPTO Web site:
The present invention, generally speaking, provides a hardware graphics accelerator for use in a computer system having a data processor, a system bus, and a memory subsystem including both main memory and video memory. The hard-ware graphics accelerator includes a datapath controller connected to the system bus and to the memory subsystem for receiving data from the memory subsystem, performing an operation upon the data, and returning the data to the memory subsystem; and a memory controller connected to the system bus, to the datapath controller, and to the memory subsystem for controlling the memory subsystem such that at one time the datapath controller receives the data from the main memory and at another time the datapath controller receives the data from the video memory. In accordance with a further aspect of the invention, the hardware graphics accelerator includes circuitry for maintaining cache coherency when the system includes either a level-one cache only or both a level-one and a level-two cache.
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Hardware graphics accelerators are well-known and are widely-available for computers running the Windows operating system. Accelerator boards are also available for computers running under the Macintosh operating system. Such boards, although they may off-load certain task [sic], possibly including graphics tasks, from the motherboard CPU, nevertheless execute those tasks in software. There has not been available a hardware graphics accelerator for computers running under the Macintosh operating system, i.e., a QuickDraw graphics accelerator.
The Mac Observer will be looking into the patent to determine if it could be connected to recent announcements from Apple Computer. Note that as of press time, the Patent Officeis Web site was very slow. If you want to look up that patent yourself, be patient. If you run into difficulties following our link, you can visit the Officeis search page, and search for patent 6373493.