The Tripos Portable Operating system was developed in Cambridge by a group of research students and myself starting in 1977. It was a light weight multi-tasking operating system that designed to be portable. It was implemented in BCPL and assembly language, and ran on several different machines. It has not been used in Cambridge for several years. However, much of the source code is still preserved and I have constructed a demonstration version of Tripos (called Cintpos) based on Cintcode BCPL.

The current distribution of Cintpos is a major revision of the origin version I made available some years ago. Cintpos devices are implemented using Pthreads and the library facilities include random access files and input/output via TCP/IP connections. The use of Pthreads is proving to be too system dependent and I am seriously considering replacing it by a scheme using just one thread, leaving interpreter to poll devices as needed. Initial experiments indicate that this new scheme is more machine independent and has better performance.

The BCPL Cintcode and Cintpos manuals are now combined and available by clicking on: bcplman.pdf.

Free Distribution

This is not yet available but when it is it will be available free of charge for private and academic purposes. If you would like to install it on your machine, have a look at the distribution README, file and obtain a copy of cintpos.tgz or The sizes and dates of creation of these files can be found in FILES.


This distribution is not yet finished and may never be, but may be of interest in its present state.

Martin Richards, last modified 15 November 2011