AT&T UNIX PC Expansion Unit
was-John McMillan
jcm at mtunb.ATT.COM
Tue Jun 27 02:08:16 AEST 1989
In article <12821 at ea.ecn.purdue.edu> wieland at ea.ecn.purdue.edu (Jeffrey J Wieland) writes:
>We are trying to install one of these on a 3b1, but we are having
>problems getting some of the cards to work. We have the following
>configuration:
...
> In the Expansion Unit:
>
>Slot 5: Tape Controller
>Slot 6: EIA/RAM Combo Board
>Slot 7: EIA/RAM Combo Board (right hand slot, looking at back of unit)
>
>None of the EIA/RAM cards have memory installed. The serial ports in
>the EIA/RAM cards in the Expansion Unit are not recognized by the
>system software. This must have something to do with how the system
>identifies the cards to tell what hardware is installed. The manual
>for the expansion does say that any ram cards must be installed in
>the internal slots, but we thought that we would be all right since
>there is no ram installed on these boards. Is it possible to get
>these cards to work in the expansion unit? By the way, the tape
>drive controller card works fine.
Much to my unpleasant surprise... a co-worker informed me that:
The EIA/RAM cards fail in the expansion box. He'd
observed this and reported it as a bug when the
expansion box was being tested.
C.T. [who did the 3B1 chassis] did the EIA/RAM card engineering,
BTW.
My presumption is that the EIA/RAM card requires the External
Memory Select line to be driven in order to do on-board
decoding, and that the Expansion box doesn't drive this line.
Best fix would be to get the EIA-ONLY boards. Someone out
there may be able to advise a hardware fix.... I only do
software, if that.
Last week's E-mail to you was bounced.... Sorry for the delay.
john mcmillan -- att!mtunb!jcm -- Speaking for himself, only.
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