Department of Computer Science and Technology

Technical reports

Exception handling in domain based systems

Martyn Alan Johnson

September 1981, 129 pages

This technical report is based on a dissertation submitted September 1981 by the author for the degree of Doctor of Philosophy to the University of Cambridge, Churchill College.

DOI: 10.48456/tr-27


Modern operating systems allow the creation of protection domains; these enable subsystems to cooperate whilst being protected from each other. This creates a number of problems in the handling of exceptions such as the expiry of time limits or the receipt of console ‘quit’ signals. Particular problems arise when parts of the operating system are implemented as protection domains which cannot easily be distinguished from user programs by the underlying protection system.

The dissertation surveys some traditional methods of dealing with such problems, and explains why they are inadequate in a domain based system. In addition, work done on related topics in the operating system for the Cambridge CAP computer is described.

The major part of the research described is concerned with a class of exception not usually recognized by operating system designers. This arises from the observation that protection domains which implement subsystems can retain useful state information between invocations, and care needs to be taken to ensure that domains are given an opportunity to keep their private data structures in a consistent state. In particular, domains which fall into disuse need to be notified of the fact so that they can tidy up the data structures they manage before they are destroyed. An intuitively simple solution to the problem is discussed, and its limitations and implementation difficulties are noted. Refinements of the mechanism are proposed which provide an improved treatment of the problem; and it is suggested that the moderate run time overhead which these revisions impose can be minimized by providing hardware or microprogram support for the mechanism.

Full text

PDF (6.5 MB)

BibTeX record

  author =	 {Johnson, Martyn Alan},
  title = 	 {{Exception handling in domain based systems}},
  year = 	 1981,
  month = 	 sep,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-27},
  number = 	 {UCAM-CL-TR-27}