The programming language PS440 as a tool for implementing a time-sharing system

The use of assembly language for the programming of basic software of a large operating system often proves inflexible and impractical. Writing the programs in assembly language is time-consuming and expensive. Furthermore, the programs are hard to read and difficult to modify. Nevertheless, assembly languages have facilities which must be preserved when higher level programming languages are to be used for basic software. A programming language, “PS440”, is described which provides many of the advantages of higher level languages while at the same time maintaining some needed facilities of assembly language.