BIB-VERSION:: CS-TR-v2.0
          ID:: STAN//CS-TR-87-1177
       ENTRY:: April 24, 1995
ORGANIZATION:: Stanford University, Department of Computer Science
       TITLE:: Log Files: An Extended File Service Exploiting Write-Once
               Storage
        TYPE:: Technical Report
      AUTHOR:: Finlayson, R. S.
      AUTHOR:: Cheriton, D. R.
        DATE:: August 1987
       PAGES:: 16
    ABSTRACT:: A log service provides efficient storage and retrieval of
               data that is written sequentially (append-only) and not
               subsequently modified. Application programs an subsystems use
               log services for recovery, to record security audit trails,
               and for perforrnance monitoring. Ideally, a log service
               should accomodate very large, long-lived logs, and provlde
               efficient retrieval and low space overhead.

               In this paper, we describe the design and implementation of
               the Clio log service. Clio provides the abstraction of log
               files: readable, append-only files that are accessed in the
               same way as conventional files. The underlying storage medium
               is required only to be append-only; more general types of
               write access are not necessary. We show how log files can be
               implemented efficiently and robustly on top of such storage
               media - in particular, write-once. optical disk. In addition,
               we describe a general application software storage
               architecture that makes use of log files.
       NOTES:: [Adminitrivia V1/Prg/19950424]
         END:: STAN//CS-TR-87-1177