Os 6 an Operating System for a Small Computer

Part I is a general description of a simple operatirg system, which runs in a virtual machine (implemented on ~ Teal machine by an interpreter). 056 copes wi th only one user at a tiJlle, and is not a multiprogramming system: many major problews associated with large operating systems have therefore been avoided or considerably simplified. It nevertheless has several features of in:erest. including the fact that it is written almost entirely in the high-level language BePL. The most important single fe~ture, however, is the hierarchical nature of its control struc~ure, which avoids the need for a special job-control language. Part II covers the facilities for input/output, and the handling of files on the disc. The input/output system uses a very general form of stream; the filing system is designed to have a clear and logical structure.