Is The M9312 Boot Module Essential?

[Noel Chiappa]

    > From: Mattis Lind

    > What about the M9300 board? Do you have an idea what the purpose is of
    > that card? 

Yes, that one's well-documented and understood.

It's intended for use on the 'B' UNIBUS of the RH11-AB, in deployment
configuratons where that UNIBUS is in use, but there's no CPU on it to
respond to NPR bus requests.

(See: http://www.bitsavers.org/pdf/dec/unibus/RH11_Peripheral_Controller_Course.pdf
pg. 11 for an example; the 'B' UNIBUS of the -11/45 is used for a separate
path into the 45's dual-port FASTBUS memory.)

On such a UNIBUS, the M9300 is used at the start of the bus, and is jumpered to
allow on-board circuitry to respond to an NPR with an NPG.It also has a SACK
timeout capability, documented in:

  http://www.bitsavers.org/pdf/dec/unibus/RH11-AB_OptionDescr.pdf

on pp. 69-70, but I'm not fully familiar with that.

	Noel