README
1 H. Peter Anvin <hpa@zytor.com>
2 June 13, 2004
3
4
5User tools for zisofs:
6
7The user tools for zisofs come in two parts: a utility "mkzftree" and
8mkisofs, which is part of the cdrtools package. cdrtools 1.11a20 or
9later is required.
10
11First create a directory tree containing compressed files:
12
13 mkzftree input_dir compressed_dir
14
15mkzftree will not overwrite an existing directory; you may want to "rm
16-rf" the directory tree if you are doing this from a script:
17
18Second, invoke the patched mkisofs with the -z option:
19
20 mkisofs -z -R [other options] -o compressed.iso compressed_dir
21
22IMPORTANT: you *must* enable RockRidge (-R or -r) since this is an
23extensions to the RockRidge specification. Without RockRidge, -z will
24have no effect.
25
26Note that if there are files you do not want compressed (for example,
27files involved in booting, or README files you want to be readable
28under all circumstances) you can simply put them in a separate tree
29and not run mkzftree on that tree.
30
31mkzftree will not compress files that end up larger when compressed;
32if you want it to compress the files anyway, you can give the -f
33option to mkzftree.
34
35mkzftree also accepts a -u option (uncompress), which can be used to
36convert a compressed tree back to normal form. This can be used to
37read a zisofs CD-ROM on a machine without zisofs kernel support.
38
39This version of mkzftree supports a -p option (parallelize.)
40Specifying -p and a parallelism (e.g. -p4) allows files (up to the
41number specified) to compress in parallel. Depending on your setup
42and your data set size, this might speed things up if you are not
43completely I/O bound. Use -p0 to completely disable parallel
44execution; this is the default.
45