Do you Know What a Transputer Is?

The transputer (TRANSistor comPUTER) was anand it required a multitasking operating system to take
innovative computer design of the 1980s from INMOS,full advantage of the transputer hardware. Transputers
a British semiconductor company based in Bristol.were intended to be programmed using the occam
When the transputer was first reveiled, many thoughtprogramming language, which had also been
this exceptional concept should be the next revolutiondeveloped inhouse at INMOS, and allowed to directly
in microprocessor technology. As you may alreadytake advantage of the transputer hardware design.
have guessed, things didn't happen as expected: today,Later on other languages such as C, FORTRAN, Ada
the transputer is a largely forgotten concept (althoughand Pascal became available too.
some initial ideas may be found in modern processorOne of the major disadvantages of the transputer
architectures).was the lack of an MMU or virtual memory support,
In the early 1980s it became clear that conventionalwhich prevented UNIX to be ported to the transputer
CISC processors were very limited in terms ofarchitecture (although there were ports of some
scalable performance. One concept to solve theUNIX-like OSes).
problem was RISC, which became the defactoThe first transputers were announced in 1983 and
standard for high performance workstations in the latereleased in 1984, and various models followed during
1990's. As RISC architectures were quite expensive inthe later 1980's. The final problem of the transputer
most cases (although ARM was not), the transputermay have been that it was still too costy to compete
was intended to offer high end performance withoutin the microcontroller market, while it coulnd't complete
being costy.with the growing success off the high end RISC
The idea behind the transputer was quite simple:designs. At the end, the was no real market for the
instead of creating a very complex processor, thetransputer.
transputer consisted of a family of chips. Each chipAfter many technical problems and delays during the
had a very simple design and multiple chips could bedevelopment of the next generation T9000 transputer,
wired together to form an entire computer. EachINMOS got into financial trouble and was finally sold to
transputer chip was in fact some kind of aSGS-Thomson, whose focus was the embedded
microcontroller and was able to boot and operate bysystems market, and eventually the T9000 project
itself, it had its own RAM, a serial bus and anwas abandoned.
embedded real-time OS, but it fulfilled only very fewThe most well known machine may have been the
complex tasks. Computer vendors would thenAtari Transputer Workstation, which was first
combine transputer chips like building blocks and designintroduced at the November 1987 COMDEX under the
a system that would fulfill specific requirements.name Abaq. It was basically a modified Atari Mega ST
A single transputer chip could be used to power a diskwith 512kB of RAM connected to a 20 MHz T800-20
controller for example, while larger numbers of themtransputer board and 4MB of RAM, plus a Blossom
could be used to create a high end workstation. Thevideo system with 1MB of dual-ported RAM. A fully
advantage of the design was its extreme scalabilityequipped Atari Transputer Workstation could contain
and its low cost hardware. The transputer chip core17 transputers offering 10 MIPS each.
itself was a simplified, microcoded CISC-like 8-bitAtari used HeliOS as operating system on this
processor (it ran a real-time OS to control themachine, as UNIX could not be ported because of the
processor), while the available processors can belack of a transputer MMU. Nevertheless this allowed
categorised into three groups: the 16-bit T2 series, thethe Atari Transputer Workstation to run a large
32-bit T4 series and the 32-bit T8 series with 64-bitnumber of standard Unix utilities, including the X
IEEE 754 floating-point support.Window System as the machine's graphical user
The transputer was a parallel architecture by design,interface (GUI).