Ethernet, Aloha and CSMACD 2396

ref:

the whole saa & terminal emulation forever

overflowed into a number of areas.

romp-pcrt

had done a customer 16bit 4mbit-sec t-r card ... and then the group was mandated that they had to use the PS2 microchannel 16mbit-sec t-r card for RIOS-6000.

the problem was that the PS2 card had the SAA and terminal emulation design point where configurations had 300 PCs per t-r lan; bridged, sharing common theoritical 16mbit (but in acutally much less), not routers, no gateways, etc. SNA didn't have a network layer ... just table of physical mac addresses ... modulo when APPN was introduced. We use to kid the person responsible for APPN that he should stop wasting his time trying to further kludge up SNA (the SNA group had non-concurred with even announcing APPN, there was a several week escalation process and the APPN announcement letter was rewritten to not imply any relationship between APPN and SNA).

In any case, the pc-rt & rios market segment was supposedly high-performance workstations, client-server, and distributed environment. The custom pcrt 16bit 4mbit-sec t-r card actually had higher per card thruput than the PS2 32bit 16mbit-sec t-r card (again the saa terminal emulation paradigm.

the pcrt-rios market segment required high per card thruput for high performance workstations and servers (in client-server environments where traffic is quite asymmetrical).

in this period, a new generation of hub-spoke enet cards were appearing (with new generation of enet controller chips like the 16bit amd lance), where each card was capable of sustaining full 10mbit (aka a server could transmit 10mbit-secs serving a client base having aggregate 10mbit-sec requirements).

by comparison, the microchannel 16mbit t-r environment actually had lower aggregate thruput and longer latencies ... AND the available cards had per card thruput designed to meet the terminal emulation market requirements (and one could say that the lack of high thruput per card also inhibited the evoluation of client-server ... as well as the 3-tier middle-layer-middleware paradigm that we were out pushing).

my wife had co-authored and presented a response to a gov. request for high integrity and operational campus-like distributed environment ... in which she had originally formulated a lot of the 3-tier principles.

we then expanded on the concepts and were making 3-tier and "middle layer" presentations at customer executive seminars ... heavly laced with high-performance routers aggregating large number of enet segments. instead of having 300 machines bridged, sharing single 16mbit t-r, you had 300 "clients" spread across ten or more enet segments ... with servers having dedicated connectivity to the high-speed routers. other components then were used to stage and complete the 3-tier architecture. a couple of past posts in answer to question on the origins of middleware thtp:--www.garlic.com-~lynn-96.html#16 middle layer thtp:--www.garlic.com-~lynn-96.html#17 middle layer

this also contributed to the work that we did coming up with the ha-cmp product

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