Last update: Feb 13, 1994
Last update: Sun March 10, 1996
Last update: Tue April 30, 1996; converted to HTML.
Last update: Sat Aug 10, 1996; link to tForth article.


is a Forth with parallel facilities. It generates code for the INMOS range of transputers.

From 1990 to 1994, tForth was the main project of the DFW, the Dutch Forth Workshop. tForth implements all words of the current ANS-Forth standard (all words). We consider it debugged. Here is our EuroForth '92 presentation.

Parallel Forth?

Transputers have a name with regards to parallel programming, especially in combination with the OCCAM language.

The main feature of tForth is that it removes the rigidity of existing C and OCCAM environments. It is not too long ago that INMOS refused to disclose details about the transputer instruction set and insisted its customers program in OCCAM exclusively. The DFW feels that some users will be more productive using Forth, certainly in the earlier stages of the development cycle (using tForth as a rapid prototyping language).

Standard features

Features especially for the transputer

Hardware requirements

The I/O of tForth is handled with a server written in the C language. The server is currently available for MS-DOS and UNIX machines. The transputer must talk to the host via a CO12 link-adaptor chip. tForth runs acceptably with T4 or T8 transputers that have at least 200 Kbytes of RAM.

Source code for the C server is available. User functions enable the calling of any C-library on the host, and thus the host platform may process in parallel with the transputer. A server written in Forth (MS-DOS protected mode or Linux, both written in iForth) is available on request.

tForth (binaries for all T4 and T8 transputers, a DOS / UNIX server and a 400+ page manual) sells for $400. Source code for the server must be negotiated.


Willem Ouwerkerk at the DFW office in Arnhem, the Netherlands, (+31) 26 443-1-305, or use the DFW-bbs at (+31) 26 442-2-164 (9600 bps, 24 hours/day).

One of the kernel authors

is available at (e-mail