Unix File Access and Caching in a Multicomputer Environment

This paper describes the Unix file access and caching mechanisms in a version of the OSF/1 Unix operating system designed to run in a multicomputer environment. The multicomputer hardware platforms targeted can consist of hundreds or even thousands of individual nodes, where each node consists of one or more processors. The multicomputer version of OSF/1 (called OSF/1 AD) uses Mach memory objects to cache data from Unix files, and relies on an in-kernel distributed shared memory implementation to maintain coherency.