The transputer

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Section: Blog Posts
Categories: blog
Tags: computing retro tech

Transputer board

So what the heck is a transputer? Well, it is a RISC CPU design from a company in England called INMOS that was designed so that it could interface with other CPUs of the same type in a massively parallel fashion (like a mini supercomputer).

Transputer CPU

The reason it was made was because CISC CPU designs of the 1980s were getting too bulky and people thought that it would be hard to advance them (of course they were wrong - never doubt engineers!).

In order to work with other transputers, the transputer CPU was essentially a computer in a box that had a CPU, RAM (about 2KB) and serial I/O integrated onto the CPU itself.

The picture at the top of this post has a 32-bit T414 Transputer CPU running @ 15 MHz (the gold chip, as shown in the close-up to the left) and 4MB of external RAM on a board that could easily fit into a standard PC ISA slot. To add more CPUs, you simply added more Transputer boards to the free ISA slots in your PC.

Needless to say, the transputer idea died out in the early 1990s - it was a cool idea that just never caught on, and the extremely high cost of transputers made them popular only to academics in universities. Atari actually manufactured 350 transputer prototypes (see picture to the left) that ran the Helios UNIX-like OS, but that was it - the transputer was dead.

Atari Transputer

Several factors killed the transputer:

  1. Limited OS support

  2. Limited programming environment support

  3. The rise of RISC CPUs (then seen as the future of power workstations)

  4. The rapid expansion of Intel i386 CISC CPUs (which drove CPU prices down)

Ironically, however, the idea of a computer on a chip ended up catching on in modern mobile ARM processors (which have integrated CPU, memory and I/O).

Similarly, parallel processing ended up catching on later in the 1990s (Symmetric Multiprocessing or SMP) as well as today with multi-core CPUs like the Intel Core i7.

So next time you see someone with a nice smartphone or brand new Core i7 laptop, make sure that you comment about how nice their transputer is (“Whoa, nice transputer man!”). At the very least, you should get a couple of weird looks….