.(z C
.(c
.TS
center, tab(;);
| c || c | c | c | c | c |.
.br
_
System;Cache;Cache;Writing;Consistency;Cache
\^;Location;Size;Policy;Guarantees;Validation
=
NFS;Memory;Fixed;On close or;Sequential;Ask server on open
[SAND85];\^;\^;30 sec. delay;\^;\^
_
RFS;Memory;Fixed;Write-through;Sequential,;Ask server on open
[BACH87];\^;\^;\^;Concurrent;\^
_
Andrew;Disk;Fixed;On close;Sequential;Server calls client
[HOWA87];\^;\^;\^;\^;when modified
_
Locus;Memory;Fixed;On close;Sequential,;Ask server on open
[POPEK85];\^;\^;\^;Concurrent;\^
_
Apollo;Memory;Variable;Delayed or;Sequential;Ask server when lock
[LEACH83];\^;\^;on unlock;\^;\^
_
CFS;Disk;Variable;On SModel;Not applicable;Not applicable
[SCHR85];\^;\^;\^;\^;\^
_
Sprite;Memory;Variable;30 sec. delay;Sequential,;Ask server on open
\^;\^;\^;\^;Concurrent;\^
_
.TE
.)c
.(q
\fBTable 7\fR.  Comparison of file systems.  All of the systems but
Apollo, Cedar and Sprite are variants of the UNIX operating system.
The Apollo system delineates active use of a file by lock and unlock
instead of open and close. The Cedar File System (CFS) only caches
immutable files and provides a different type of cache consistency than
the other systems.  SModel is a software tool that is used to move cached
files that have been changed back to their file server.
.)q
.)z