J. David Bryan
jdbryan at acm.org
Wed Jan 24 11:45:15 CST 2007
On 13 Jan 2007 at 10:00, Richard Lynch wrote:
> In the front there is the DCPC, Memory Protection, M.E.M. (Memory
> Extension Module), 3 memory cards and Memory Controller.
Also, there should be a ribbon cable from the DCPC card to the memory-I/O
crossover PCB, and another ribbon cable connecting all of the left-side
connectors on the memory cards and controller (the right-side connectors
> I believe I can see 3 loader ROM chips installed on the CPU board
> (assuming I'm looking in the right place - front right side of the board
> as I'm facing it).
That's the correct location. Optional ROM 1 is the socket nearest the
front of the machine. 2 and 3 follow in order.
> Of the 3 optional Control Store modules in the back, the middle one is
> mounted under the CPU, but the other two are not there.
Looking from the back of the machine, the left-hand control store PCB
should always be present; it contains the base set ROMs and is connected
with a ribbon cable to the left-hand CPU board connector. If you have a
MEM card, then there should be a second control store PCB containing the
DMS instructions. The second and third boards plug into the first and
second boards respectively; no ribbon cables are used.
If the middle one is present and the left one is not, then either the base
set board is in the wrong location or it's been removed from the machine.
Part numbers on the board and/or ROMs will tell.
> The back label says "2112A" and lists the following options:
> 12978A (Writeable Control Store Diagnostic)
> 12992B (Disk boot ROM)
> 12992C (Terminal boot ROM)
> I figured out from the bitsavers document and another online document that
> these are the 3 ROM options I saw.
I've never heard of a 12978A ROM. Is that the part number stamped on the
chip? What document describes this?
> The paper tape loader ROM is soldered in with the M-series machines,
> according to the online documents I read.
That's correct. It's always loader number 0.
> 12897A (DCPC)
> 12892A (Mem Protect)
> 13187Ax2 (16k Mem)
> So it looks to me like I need some I/O boards...
First, you'll need a base set PCB, unless the one in position 2 is
> ...(13175 disk drive interface, ...
That's a "MAC" disc interface, so you'd also need the 13037 MAC controller
box and an associated drive (7905/06/20/25). An alternate would be the
13210A disc interface and a 7900/01 drive, or a 12821 HP-IB interface and a
corresponding HP-IB drive.
> ...12966 or 12968 terminal interface, ...
Note that only the newer HP RTE systems supported the 12966/8 interfaces,
and then only with HP terminals (264x, 262x, etc.). Alternates would be
the 12531 (teleprinter) or 12880 (CRT) interfaces. The latter works with a
broad range of terminals and HP OSes, although with less efficiency (more
CPU load) than the 12966/8.
> [...] and probably the other Control Store modules....
The M-Series had a small control store address space compared to the later
E/F-Series, so there were few firmware options. Beyond the base set,
you'll need the DMS instructions PCB to support your MEM card (although DMS
isn't overly relevant with 32K of memory). The 12977 Fast FORTRAN
Processor instructions help to accelerate some commonly-used routines,
although HP operating systems came with software equivalents, so it's not a
necessity. The "B" version of the FFP included the DMS instructions, so
that only one control store board was needed for both. I think DS/1000
(Distributed Systems) was the only other M-Series firmware option available
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