H. Peter Anvin <hpa@zytor.com>

			    June 13, 2004

User tools for zisofs:

The user tools for zisofs come in two parts: a utility "mkzftree" and

mkisofs, which is part of the cdrtools package.  cdrtools 1.11a20 or

later is required.

First create a directory tree containing compressed files:

	mkzftree input_dir compressed_dir

mkzftree will not overwrite an existing directory; you may want to "rm

-rf" the directory tree if you are doing this from a script:

Second, invoke the patched mkisofs with the -z option:

	mkisofs -z -R [other options] -o compressed.iso compressed_dir

IMPORTANT: you *must* enable RockRidge (-R or -r) since this is an

extensions to the RockRidge specification.  Without RockRidge, -z will

have no effect.

Note that if there are files you do not want compressed (for example,

files involved in booting, or README files you want to be readable

under all circumstances) you can simply put them in a separate tree

and not run mkzftree on that tree.

mkzftree will not compress files that end up larger when compressed;

if you want it to compress the files anyway, you can give the -f

option to mkzftree.

mkzftree also accepts a -u option (uncompress), which can be used to

convert a compressed tree back to normal form.  This can be used to

read a zisofs CD-ROM on a machine without zisofs kernel support.

This version of mkzftree supports a -p option (parallelize.)

Specifying -p and a parallelism (e.g. -p4) allows files (up to the

number specified) to compress in parallel.  Depending on your setup

and your data set size, this might speed things up if you are not

completely I/O bound.  Use -p0 to completely disable parallel

execution; this is the default.