discrete transistors

It's a thruput problem - if the main CPU has to handle every byte in and out, you're just doomed. Just about calculating (Additions per second etc.) a 286 can catch up. It's more about the I/O concepts and devices. Add a versitale IOC and blockmode operations and you could run dozends of users on a 286. Even when using a clumbsy unix like byte orientated OS. And wehn using applications, specialy designed to be aware and operate in blockmode even a hunded might be possible. Ten years ago I designed a small 286 system to act as a terminal/dial up server running a stand alone aplication and accesing a database/transactionsystem running under SIEMENS BS2000 (an /390 compatible system) - in a testrun we had up to 64 users with an accestime below 1s per full screen, with up to 12 concourent requests, even including the mainframe transaction (needed in about 70% of all requests). And still only a CPU usage of less than 20% on a 6 MHz 80286! To be honest, this system had a little helper - all serial I/O has been handled by an I/O subsystem with one Z80 for each two ports - only if a reciving transmission was completed the 286 had to act - and for sending only the data had to be transmited to the Z80 memory window via DMA. The host connection was based on a 230 kbit serial line also operating in a kind of blockmode, using a HDLC like multiplex protocoll. The neat thing was that the OS was just linear and message driven - no real time and no preemptive multitasking. Everything was just so fast that a cooperative sheme did work out quite well. So don't underestimate the power of a micoprocessor. We just bring them unde a yoke, no 'real' processor ever har to carry. Gruss H. -- Ich denke, also bin ich, also gut HRK