Wanted: PDP-11 Unibus Ethernet interface from Xerox, c. 1981

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Mar 31 08:19:12 CDT 2015

    > From: Rich Alderson

    > SAIL .. did not use the MEIS (Massbus-Ethernet Interface Subsystem) for
    > Ethernet connectivity, but rather a Unibus card from Xerox (apparently
    > used to hook -11s to D-machines) which went into the front end 11/40 on
    > the KL-10.

If this is the card I'm thinking of (we got two as part of the Xerox donation
of Altos, a Dover, etc to MIT, BITD), it's to a 3-MBit Experimental Ethernet,
not to a 10-MBit Ethernet, and so won't be much use unless you have something
else with a 3-MBit Ethernet (and of course you'd also need 3-MBit
transceivers, etc, etc).

And of courset those cards were made in very, very limited numbers; if any
survive to this day, I will be absolutely astonished.

If you have a pointer to the PDP-11 code, I can take a look at it and confirm
if it's a 3-MBit card. (The hardware packet header format is completely
different from that for a 10-MBit.)


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