Whitechapel Computer Works MG-1

[tony duell]

> 
> I just got the "Owner Operator Guide" manual for a MG-1 from a friend. I
> did some searches and found a picture on wikipedia in the article about
> Whitechapel Computer Works. (
> https://en.wikipedia.org/wiki/Whitechapel_Computer_Works )
> I also found an evaluation of the MG-1 and several contemporary
> workstations...
> http://www.chilton-computing.org.uk/acd/sus/perq_papers/perq_external/p003.htm
.> .. but then I drew a blank. It seems like these are really rare systems.
> 
> Does anyone have a system? Anyone need the manual?

I have one. I've even found it after the move (it's on a shelf behind me along
with its keyboard. Not found the mouse yet, it's probably still in one of the 
500 or so boxes still to unpack.

It's a 32016-based unix box. There are a few gotchas that I remember.

It needs a good set of NiCd cells on the power control board to start it up.
If not, you have to do a 'jumpstart' involving connecting a 9V battery to a connector
on that board. Some owners added an external socket wired there to make it 
easier to so this.

The 32016, 32018 (FPU), MMU chips, etc are in nice turned-pin sockets. The
EPROMs are in cheap sockets. Replacing the latter sockets will often get a 
dead machine going.

The boot ROMs I have need 1.5M of RAM. There is 512K on the motherboard
so it needs 2 RAM expansion cards. No real problem except that if it only
has 512K it flashes the error code for 'multi bit RAM failure' on the LED, and
nowhere in any of the manuals I have does it say it needs the extra RAM. 
Needless to say this led me a merry dance checking the arbitration logic, etc
before I realised that what it was really moaning about was the fact that I had
not plugged in the RAM expansion cards.

There is a rare adapter which adds 3 ISA slots. 8 bit ones IIRC. 

There is a graphics processor -- a sort of blitter -- which is built in TTL
and is bit serial. It wasn't fitted to later machines as it was realised that 
it was slower than doing the operations in software on the 32016.

> The system could still be around so I'm going to dig around at the
> university a while to see if I can locate it.

It looks a lot like an older PC, so it is quite easy to miss.

-tony