Madge Networks Ltd has announced a high performance Token Ring board which takes advantage of the bus-master streaming mode of the Micro Channel bus. When IBM Corp launched its new top end Model 90 and 95 XP PS/2s in May, it supported bus-master streaming – a mode of operation, hitherto restricted to RS/6000s which allowed much faster use of the bus. There’s been a dearth of adaptor boards exploiting the high speeds until now, and the Chalfont St Giles, Buckinghamshire company reckons it has the first board to take advantage of the streaming mode in the shape of its Smart 16/4 MC32 Ringnode. Quoted throughputs using the streaming technique are 40Mbytes per second, compared with 20Mbytes per second in conventional mode. Both figures may seem unnecessarily high, considering the 16Mbps maximum Token Ring throughputs, but the point is to minimise the time that the CPU and bus is tied up moving traffic. The company says that servers in particular benefit from reduced bus and CPU utilisation so that more local area network adaptor boards can fit onto a single server. Apart from Novell Inc’s NetWare at the server, the company claims that the adaptor boards can improve productivity in workstations running multi-tasking operating systems such as Unix and OS/2. The unleashing of the Micro Channel stream mode makes the architecture more competitive with EISA bus-based machines, which have been able to exploit a similar burst mode since inception. While souped-up Micro Channel should now work at 40Mbytes per second, the top speed of the EISA bus is 33Mbytes per second, retaining compatibility with older AT boards. Nonetheless one Madge product manager commented that, in practice, there is little real difference between the throughputs of the two architectures.
