David May's Transputer Page

From 1979 I worked in Bristol as the architect of the Inmos transputer and still have a large collection of material about the design, the products and the associated programming language occam which I designed alongside the transputer instruction set.

I am often asked about the history of Inmos and the transputer, so I have started to put together these pages. For the moment, here are a couple of photographs:
B0042 board
C104 board

The B0042 board contains 42 transputers connected via their links into a 2-dimensional array. A number of them were built following a manufacturing error - all of these transputers were inserted into the packages in the wrong orientation so were fully functional but unsaleable. I had them all (around 2000) written off for engineering use and we built the B0042 'evaluation' boards! Many of these were given to Southampton University where they were assembled into a 1260 processor machine and used for experimental scientific computing. Inmos used them in a number of exhibitions (in a box of 10 boards - 420 processors) drawing Mandelbrot sets in real time!

The C104 board contains one of a very small number of C104 message routing chips. This chip was originally developed alongside the T9000 transputer with its dynamic message routing architecture although in fact it was designed as a component for building interconnection networks (switching fabrics) in general. It had 32 100Mbit bidirectional links internally connected via a full crossbar. The transport protocol on the links was standardised as IEEE1355 and also used in IEEE1394 (Firewire). Routing was done using an interval-labelling technique with short message headers. There was support for hot-spot avoidance in large networks using randomisaton. I think the C104 was the first switch chip designed in state-of-the-art VLSI (around 2 million transistors). Unfortunately very little effort was available to market and support this chip and very few were made - I think most of them were on development boards like this one.

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