QuickRing was a gigabit-rate interconnect that combined the functions of a computer bus and a network. It was designed at Apple Computer as a multimedia system to run "on top" of existing local bus systems inside a computer, but was later taken over by National Semiconductor and repositioned as an interconnect for parallel computing. It appears to have seen little use in either role, and is no longer being actively worked on. However it appears to have been an inspiration for other more recent technologies, such as HyperTransport.
QuickRing started as an offshoot of the fabled Futurebus project, which started in the late 1970s under the aegis of the IEEE. Realizing Futurebus was doomed, several of the main designers left the effort in 1987 to try again on smaller projects, leading to both QuickRing and SCI. In the case of QuickRing the main proponent was Paul Sweazey of National Semiconductor, who had hosted Futurebus's cache coherency group. Sweazey left National Semiconductor and moved to Apple Computer's Advanced Technology Group, where the new system was developed.
The system was first announced publicly at the 1992 Worldwide Developers Conference, positioned primarily as a secondary bus for computer systems to carry multiple streams of digital video without using the existing backplane bus. Apple was particularly interested in this role due to the limitations of their current NuBus systems in terms of speed. They envisioned various video cards using a second connector located near the "top" (opposite the NuBus connector) to talk to each other. Optionally, one of the cards would produce compressed output, which could be sent over the NuBus for storage or display. Before any commercial use of QuickRing, newer versions of PCI started appearing that offered performance close enough to QuickRing to make its role redundant. Apple switched to an all-PCI based computer lineup starting in 1995, and in one of their general downsizings in the early 90s, Apple dropped their funding for QuickRing.
In response Sweazey moved back to National Semiconductor, who positioned QuickRing as a high-speed interconnect. Here it had little better luck, competing against SCI on one hand, and ever-faster versions of Ethernet on the other. Efforts were made to standardize QuickRing inside the existing VMEbus system using some redundant pins in response to an industry effort to standardize parallel processing hardware, but nothing ever came of this. The US Navy announced several tenders for QuickRing products for sonar data processing (for which they had originally had Futurebus+ developed), but it is unclear whether or not it was used in this role. National eventually lost interest, and the system essentially disappeared in 1996. Similar products, notablty SKYconnect and Raceway, were also standardized in this role, but seem to have seen little use as well.
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