Another interesting computer on ebay

[Roger Holmes]

> From: Richard <legalize at xmission.com>
>    Roger Holmes <roger.holmes at microspot.co.uk> writes:
> 
>> ither. The 29000 processor [...]
> 
> 2900, not 29000.  The 29xx is a bit-slice CPU design made up of a
> bunch of chips.  The 29000 is a single chip CPU that came later.

Quite right. Brain parity error, but the difference is only a 0 :-)

IIRC we used six 4 bit slices and a controller chip in one of our machines called CHLL which was a two off special, one bench prototype and one flyable prototype. I got to modify some of the microcode for the bench machine and worked on the CHLL 'compactor' which was really a compiler but the idea was that the instruction set was a Compacted High Level Language so the compiler was very simple (it wasn't) and he machine would be very efficient (it wasn't). Trouble was someone got carried away and implemented much of Algol 60 instead of the Coral 66 they had been asked to do. I just cleaned it up and got it through its acceptance test with the minimum of work. I remember telling them I could fix a bug easily (by incrementing a field for a particular instruction as it went through the back end of the code generator) but that it was not the right place to fix it. I was told to fix it in the wrong place and I did so and they closed down the project. Apparently the flyable prototype was used at the Royal Aircraft Establishment at Farnborough - as a door stop!

At the time I had neither the experience nor the confidence to tell them they were wrong, I was just a year out of University, supposedly a trainee programmer working for a huge company (4000 staff at just the one site I worked and many other sites too) and its only looking back years later I realised fully what had gone on.