22 Apr
2001
22 Apr
'01
3:18 p.m.
From: Tony Duell <ard(a)p850ug1.demon.co.uk>
AFAIK it is not backwards-compatible, at least in the
sense that no
10Mbps ethernet controller supports the 3Mbps data rate (at least, I've
never seen one that does).
Neither have I. Also Eithernet AKA 802.x was never that slow. The
3 mb/s stuff I'd always called ARCNET.
There were no single-chip ethernet controllers, if
that's what you're
asking. The ethernet circuitry for the classic PERQ (which was generally
10Mbps, but early enough that single-chip controllers didn't really
exist) is a 2910 sequencer, some microcode PROMs, some 9403 FIFOs, and a
lot of TTL glue logic (and some comparator-type parts for the interface
to the AUI connector). It takes up about 1/3rd of the EIO board.
Correct, there wasn't current LSI that was fast enough in the beginning.
The would change fairly quickly by 1984-85ish.
Allison