The File System of a Logic Operating System

This paper describes the file system of an operating system for a logic inference machine. The file system is composed of a file system device and a collection of file system servers. The former provides the basic services of creation, access (reading or writing), removal, and stable storage of files. It realizes a simple, though powerful model: a file store as a special type of name server maintaining associations between identifiers and entities. A file is then a pair, , of terms. Clients gain access to a file by sharing the file content term with the file system device. Reading the file corresponds to examination of the term; writing, to instantiation. There is no need of explicit read or write operations, or of file closure. File system servers enhance or modify this basic file abstraction. They can provide features of more conventional file systems, such as hierarchical directories or fixed, structured file formats.

Concurrent Prolog is assumed as the underlying machine language and the operating system implementation language. However, the ideas are also applicable to other parallel logic programming languages, such as PARLOG.

As a prerequisite to describing the file system, the Concurrent Prolog machine model is presented, as well as an overview of the entire operating system design.