A cached WORM file system

Sean Quinlan
1991 Software, Practice & Experience  
This paper describes a general-purpose file system that uses a writeonce-read-many (WORM) optical disk accessed via a magnetic disk cache. The cache enables blocks to be modified multiple times before they are written to the WORM and increases performance. Snapshots of the file system can be made at any time without limiting the users' access to files. These snapshots reside entirely on the WORM, are accessible to the user via a second read-only file system, do not contain multiple copies of
more » ... hanged data, and can be used to rebuild the file system in the event that the disk cache is destroyed. The file system has been implemented as part of Plan 9, an experimental operating system under development at AT&T Bell Laboratories.
doi:10.1002/spe.4380211203 fatcat:lghdbypbefc3thx2aotkvfqt3q