1 Firstly, let me say that UMSDOS is going through some major code changes,
2 and has some KNOWN BUGS (and quite a few unknown :-). Please read
3 fs/umsdos/README-WIP.txt for more information on current status. Thanks.
4
5 ----------------------------------------------------------------------------
6 Very short explanation for the impatient!
7
8 Umsdos is a file system driver that run on top the MSDOS fs driver.
9 It is written by Jacques Gelinas (jacques@solucorp.qc.ca)
10 and is currently maintained by Matija Nalis (mnalis@jagor.srce.hr)
11
12 Umsdos is not a file system per se, but a twist to make a boring
13 one into a useful one.
14
15 It gives you:
16
17 long file names
18 Permissions and owners
19 Links
20 Special files (devices, pipes...)
21 All that is needed to be a linux root fs.
22
23 There is plenty of documentation on it in the source. A formatted document
24 made from those comments is available from
25 sunsite.unc.edu:/pub/Linux/system/Filesystems/umsdos.
26
27 You mount a DOS partition like this:
28
29 mount -t umsdos /dev/hda3 /mnt
30 ^
31 ---------|
32
33 All options are passed to the msdos drivers. Option like uid,gid etc are
34 given to msdos.
35
36 The default behavior of Umsdos is to do the same thing as the msdos driver
37 mostly passing commands to it without much processing. Again, this is
38 the default. After doing the mount on a DOS partition, nothing special
39 happens. This is why all mount options are passed to the msdos fs driver.
40
41 Umsdos uses a special DOS file --linux-.--- to store the information
42 which can't be handled by the normal MS-DOS filesystem. This is the trick.
43
44 --linux-.--- is optional. There is one per directory.
45
46 **** If --linux-.--- is missing, then Umsdos process the directory the
47 same way the msdos driver does. Short file names, no goodies, default
48 owner and permissions. So each directory may have or not this
49 --linux-.---
50
51 Now, how to get those --linux-.---.
52
53 \begin joke_section
54
55 Well send me a directory content
56 and I will send you one customised for you.
57 $5 per directory. Add any applicable taxes.
58 \end joke_section
59
60 A utility umssync creates those. The kernel maintains them. It is available
61 from the same directory above (sunsite) in the file umsdos_progs-0.7.tar.gz.
62 A compiled version is available in umsdos_progs-0.7.bin.tar.gz.
63
64 So in our example, after mounting mnt, we do
65
66 umssync .
67
68 This will promote this directory (a recursive option is available) to full
69 umsdos capabilities (long name, etc.). However, an "ls -l" before and after
70 won't show much difference. The files which were there are still there, but
71 now you can do all this:
72
73 chmod 644 *
74 chown you.your_group *
75 ls >THIS_IS.A.VERY.LONG.NAME
76 ln -s toto tata
77 ls -l
78
79 Once a directory is promoted, all subdirectories created will inherit that
80 promotion.
81
82 What happens if you boot DOS and create files in those promoted directories ?
83 Umsdos won't notice new files, but will signal removed files (it won't crash).
84 Using umssync in /etc/rc will make sure the DOS directory is in sync with
85 the --linux-.---.
86
87 It is a good idea to put the following command in your RC file just
88 after the "mount -a":
89
90 mount -a
91 /sbin/umssync -i+ -c+ -r99 /umsdos_mount_point
92
93 (You put one for each umsdos mount point in the fstab)
94
95 This will ensure nice operation. A umsdos.fsck is in the making,
96 so you will be allowed to manage umsdos partitions in the same way
97 other filesystems are, using the generic fsck front end.
98
99 Hope this helps!
100
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