Cromemco's Word Interleaved Data Exchange Bus (WIDE-Bus) was a hosted bus that operated over the standard IEEE-696 bus. WIDE-Bus allows 32-bits of data to be transferred by utilizing interleaving techniques more commonly used on mainframe computers. The bus ran between the XXUprocessor board and the 2048KZ memory board. The MC68020 processor on the XXU generates queries to memory in 32-bit data packets, It then segmented the query into two equal sized packets which it transmitted over the WIDE-Bus in a serial fashion. The 2048KZ accepted both packets of information, decodes them, and then locates the proper address in memory. Once the required data is located, the 2048KZ completed the cycle by transmitting it to the processor in dual 16-bit packets.
This technique allowed Cromemco to maintain the growth path provided by the standard IEEE-696bus, while at the same time matching the performance of systems utilizing such dedicated 32-bit buses as VME. The most widely noted implementation of this interleaving (or multiplexing) technique was on DEC's MicroVAXII. DEC's Q-Bus is a 16-bit bus which can transmit data in 32-bit segments using similar interleaving techniques as those implemented by Cromemco.
The implementation of WIDE-Bus combined with an integrated processor and fast floating point co-processor, and triple-cache architecture provides XXU systems such as the CS420 with the power to generate over 1,050,000 Whetstones.
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