The Solo Operating System: A Concurrent Pascal Program

  • Per Brinch Hansen


This is a description of the single-user operating system Solo written in the programming language Concurrent Pascal. It supports the development of Sequential and Concurrent Pascal programs for the PDP 11/45 computer. Input/output are handled by concurrent processes. Pascal programs can call one another recursively and pass arbitrary parameters among themselves. This makes it possible to use Pascal as a job control language. Solo is the first major example of a hierarchical concurrent program implemented in terms of abstract data types (classes, monitors and processes) with compile-time control of most access rights. It is described here from the user’s point of view as an introduction to another paper describing its internal structure.


File System Machine Language Concurrent Program Abstract Data Type Disk Pack 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. P. Brinch Hansen 1974. Deamy—A structured operating system. Information Science, California lnstitute of Technology, (May), (out of print).Google Scholar
  2. P. Brinch Hansen 1975. The programming language Concurrent Pascal. IEEE Trans. on Software Engineering, 1, 2 (June).Google Scholar
  3. P. Brinch Hansen 1976a. The Solo operating system: job interface. Software—Practice and Experience, 6, 2 (April—June) .Google Scholar
  4. P. Brinch Hansen 1976b. The Solo operating system: processes, monitors and classes. Software—Practice and Experience, 6, 2 (April–June) .Google Scholar
  5. P. Brinch Hansen 1976c. Disk scheduling at compile-time. Software—Practice and Experience 6, 2 (April—June), 201–205.CrossRefGoogle Scholar
  6. K. Jensen and N. Wirth 1974. Pascal—User manual and report. Lecture Notes in Computer Science, 18, Springer-Verlag, New York.MATHCrossRefGoogle Scholar
  7. B. W. Lampson 1974. An open operating system for a single-user machine. In Operating Systems, Lecture Notes in Computer Science, 16, Springer Verlag, 208–217.Google Scholar
  8. J. E. Stoy and C. Strachey 1972. 0S6—an experimental operating system for a small computer. Comput. J., 15, 2.Google Scholar

Copyright information

© Springer Science+Business Media New York 1975

Authors and Affiliations

  • Per Brinch Hansen

There are no affiliations available

Personalised recommendations