The solo operating system: A concurrent pascal program
Per Brinch Hansen · Software Practice and Experience · 1976
Abstract 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.