16 Dec
1999
16 Dec
'99
8:57 a.m.
On Wed, 15 Dec 1999, John Lawson wrote:
In the 11/44 system which is now occupying my evenings... there
are three Massbuss adaptors [M5904]. I actually have an RA90+power
supply out in the garage, condition unknown at this time.. I don't
know anything at all about the Massbuss and it's peripherals, save
that its serial and kinda fast.
The RH11 UNIBUS MASSBUS adapter actually consists of several boards:
M5903 MASSBUS terminal tranceiver
M5904 MASSBUS control tranceiver
M7294 MASSBUS data buffer and control
M7294-YA Modified M7294 for RH11-C (used on DECSYSTEM-2020)
M7295 MASSBUS bus control (RH11-A only)
M7295-YA Modified M7295 for RH11-B
M7296 MASSBUS control and status registers
M7297 MASSBUS parity control
The appropriate boards live in their own section of backplane.
(Does anyone know what the reason is behind Digital putting a "-YA" suffix
on the module number of a board that's been modified somehow? Does it
stand for "Yet Another"...? :-) )
The RA90 is an MSCP drive; you need a UDA50 to run it. MASSBUS drives are
drives like the RP04/5/6 (washing-machine looking), and RM02/03/04/80 (not
quite washing-machine size, but still pretty big). The RP07 is also a
MASSBUS drive, but I am not sure if it will run off of an RH11 (I think
it was originally meant to be attached to an RH20 interface on a
DECsystem-10 or DECSYSTEM-20).
--Pat.