Department of Computer Science and Technology

Technical reports

Portable system software for personal computers on a network

Brian James Knight

204 pages

This technical report is based on a dissertation submitted April 1982 by the author for the degree of Doctor of Philosophy to the University of Cambridge, Churchill College.

DOI: 10.48456/tr-26


This dissertation is concerned with the design of the portable operating system TRIPOS, and its use as the basis for an operating system to run in ‘single connection’ computers – that is, computers whose only peripheral is an interface to a local area network.

TRIPOS is a lightweight, yet powerful, multi-tasking operating system aimed at personal minicomputers. It is designed to be relatively straightforward to transport to new hardware, providing an almost identical user interface and program environment on each machine. Particular emphasis has been placed on avoiding unnecessary complexity, in order to make it simple to understand, explain, and adapt for special purposes. The majority of the system and utilities are written in the language BCPL, and can be moved without change to different computers. They run on a kernel and device drivers written in assembly language for each particular machine. The user’s view of the system is presented first, with samples of console dialogue, and then its internal structure is described.

The main part of the work described concerns the building of a portable operating system presenting user and program interfaces as similar as possible to ordinary TRIPOS, but running in processors connected only to a local area network – the Cambridge Ring. The system makes use of ‘server’ computers on the ring in order to gain access to disc storage, terminals, and printers. Several methods are investigated for using the primitives provided by a universal file-server to construct a filing system which can be shared by machines of different types. Some conclusions are drawn on the effects of distributing operating system functions in this way.

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BibTeX record

  author =	 {Knight, Brian James},
  title = 	 {{Portable system software for personal computers on a
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-26},
  number = 	 {UCAM-CL-TR-26}