Hi all,
I have a friend that used to work on/with the Unisys stuff. I have
most of a machine in my basement, but never fired it up. He also has a
complete machine, and hasn't fired it up recently, but believes it will
run. I forwarded Dave's original email to him and he replied below. If
any of you need further help, let me know and I'll pass the questions on
to him and he might answer directly. His big thing is that he already
gets a ton of email (good,bad and ugly) and is cautious about getting
more, or joining the group. Very interesting about what he says about
booting from the floppy. He used to support a bunch of these machines,
so I am pretty sure he knows his stuff, but to not boot a floppy is unique.
Cheers,
Joe Heck
Unisys info:
A7 came in a few varieties....
A7-311 first release basically a 486 souped up with several mainframe
boards in it.
the host operating system was OS/2 2.1
The mainframe processor (aka SCAMP) is the "do not press" chip.
the a7-411 was similar to the 311 but in a rack mount 6u chassis
then came the A7-811 which went up to a P-90 but still ran os/2 etc...
the memory boards (daughter boards) on the processor card are (i think)
500K Words each, yes i said words...
the A series uses a 48 bit user word with a 4 bit tag (52 bit words)
the a7-811 processor had a second card strapped to the proccessor that
would allow a max of about 3-4 Mg Words.
The long net card is really the mainframe network interface, 10B2 or
AUI, in the right os it will support tcp/ip
There should also be a long scsi card, i believe a 1744 or there
abouts.. this would be the primary mainframe bus.
the config error is usually due to:
a) a bad cmos battery
b) re-arranged cards
c) missing cards.
you need the SCU for the machine to fix the cmos to get rid of the error...
Unisys was very picky and nothing else would work
you should be able to boot from either the CD-rom or the QIC tape. you
usually cannot boot from the floppy.
The same server cabinet also came with SYSVr4 Unix, be sure you DO NOT
use the SCU for the unix box as the tags for the mainframe cards are wrong.
once you boot into os/2 (if it's there)
you'll get into the a-series maintenance mode support and the into the
a-series.
be sure that you DO NOT use a ps/2 style mouse as that interrupt is
needed for the mainframe.
once booted, the mainframe will try to boot from it's own boot drive.
the a series boot scsi disks are NOT 512 byte sectors, they are 180 byte
sectors and will not look right to any pc software. there is special
firmware on the drive to enable the correct size sectors, etc.
also, if you have 4mm or 8mm drives for it, they have custom firmware.
once booted, you should be able to get to an ODT screen,
enter ??MARC
if that is taken, about 3-4 minutes later you should see a login
screen.!!!! if so, we can talk from there.
MCP is the master control program and runs the a series line.
I have an A7-811 here and i think it still runs.