Implementing a shared file system on a HIPPI disk array

Shared file systems which use a physically shared mass storage device have existed for many years, although not on UNIX based operating systems. This paper describes a shared file system (SFS) that was implemented first as a special project on the Gray Research Inc. (CRI) UNICOS operating system. A more general product was then built on top of this project using a HIPPI disk array for the shared mass storage. The design of SFS is outlined, as well as some performance experiences with the product. We describe how SFS interacts with the OSF distributed file service (DFS) and with the CRI data migration facility (DMF). We also describe possible development directions for the SFS product.