practical applications for synchronous and asynchronous communication

Rob Warnock

pc-rt had done a custom 4mbit t-r card for its 16bit bus but. the rs-6000 was forced to use the ps2 microchannel 16mbit t-r card (32bit bus) ... rather than doing its own. One of the issues with the ps2 microchannel 16mbit t-r card ... was that the per-card thruput was actually lower than the custom pc-rt 4mbit t-r card (ps2 16mbit t-r design point was hundreds of PS2s sharing the same 16mbit t-r).

my wife had co-authored and presented a response to a gov. secure campus-like network ... in it, she had postulate some of the fundamentals of 3-tier architecture. We then expanded on that in conjunction with ethernet and other technology and started presenting it at customer executive meetings.

we got hammered from the SAA and T-R crowd .... who possibly could be characterized as trying to put the client-server genie back in the bottle ... and we were out pitching 3-layer architecture, middleware, etc.

one of the things that the t-r group were claiming was enet typically degraded quickly to less than 1mbit thruput. the buttumptions for this appeared to be an early 3mbit enet technology before there was listen before transmit. In this timeframe there was an ACM sigcomm article that measured in most typical enet deployments ... it degraded to 8.5mbit effective thruput under worst case scenario ... all stations in tight low-level device driver loop constantly transmitting minimum sized packets. By comparison, it was rare to see 16mbit t-r getting better than 8mbit effective thruput ... and its nominal message latency was typically much greater than the nominal enet latency.

disclaimer ... my wife is named as co-inventor on one of the early token pbutting patents from the 70s.

some past postings on the enet & t-r issues ... Ms employees begging for food) times? times?

some old 3-tier postings: week of his professional life 33 Typing Element) 33 Typing Element) come from?