3 fs \- file server, dump
7 The file server was the main file system for Plan 9.
8 It was a stand-alone system that ran on
10 It served the Plan 9 protocol via the IL/IP
11 protocols on Ethernets.
12 The name of the main file server at Murray Hill was
15 The file server does not require authentication on
17 by default. To require all users except
19 to provide authentication tickets on each
23 toggle switch command (see
26 The group numbered 9999, normally called
29 on the file server. Any user belonging to that group has
30 attenuated access privileges. Specifically, when checking such
31 a user's access to files, the file's permission bits are first ANDed
32 with 0770 for normal files or 0771 for directories. The effect is
33 to deny world access permissions to
36 when walking directories.
40 is always allowed to attach to
42 without authentication but has minimal permissions.
45 maintains three file systems
46 on a combination of disks and
47 write-once-read-many (WORM) magneto-optical disks.
50 is a simple disk-based file system not backed by
54 is a worm-based file system with a disk-based
58 to overcome the write-once property of the worm.
59 The cache also holds recently accessed
60 non-modified blocks to
61 speed up the effective access time of the worm.
63 (usually daily at 5AM) the modified blocks in the
67 traffic to the file system is halted and the
68 modified blocks are relabeled to the unwritten
71 the file system traffic is continued and
72 the relabeled blocks are copied to the worm by
76 Each time the main file system is dumped,
77 its root is appended to a subdirectory of the dump file system.
78 Since the dump file system is not mirrored with a disk
81 The name of the newly added root is created from the date
83 .BI / yyyy / mmdds\f1.
92 is a sequence number if more than
93 one dump is done in a day.
97 For the subsequent dumps
101 The root of the main file system
102 that is frozen on the first dump
106 in the dump file system.
108 Place the root of the
112 and show the modified times of the MIPS C compiler
113 over all dumps in February, 1992:
117 ls -l /n/dump/1992/02??/mips/bin/vc
120 To get only one line of output for each version of the compiler:
123 ls -lp /n/dump/1992/02??/mips/bin/vc | uniq
128 file system available in directory
132 mount -c /srv/boot /n/emelieother other
143 ``A Cached WORM File System'',
145 Software \- Practice and Experience,
148 For the moment, the file server serves both the old (third edition) and new (fourth
149 edition) versions of 9P, deciding which to serve by sniffing the first packet on each
152 Required IL, thus now deprecated.