Sort the order of file data on the CD/DVD

Note: this option does not sort the order of the file names that appear in the ISO9660 directory. It sorts the order in which the file data is written to the CD image.

This option is useful in order to optimize the data layout on a CD.

To use, type something like:

mkisofs -o cdimage.iso -sort sort_file other_options cd_dir

The file 'sort_file' contains two columns of:

filename	weight

where filename is the whole name of a file/directory as mkisofs will see it and weight is a whole number between +/- 2147483647

The files will be sorted with the highest weights first and lowest last. The default weight is zero.

If the filename is a directory name, then all the files in that directory (and sub-directories) will use its weight as their default weight.

e.g.

If the directory 'cd_dir' contains two directories called 'dir1' and 'dir2' with files 'A', 'B' and 'C' in dir1 and 'X', 'Y' and 'Z', the the file 'sort_file' could look something like:

cd_dir/dir2	1000
cd_dir/dir2/Y	2000
cd_dir/dir1/B	-2000
cd_dir/dir1/A	-8000

Note: There must be only one space or tab character between the filename and the weight and the weight must be the last characters on a line. The filename is taken to include all the characters from the first in a line, up to, but not including the last space or tab character on a line. This is to allow for space characters to be in, or at the end of a filename.

The command:

mkisofs -o cdimage.iso -sort sort_file cd_dir

will sort the above file data as:

cd_dir/dir2/Y
cd_dir/dir2/X
cd_dir/dir2/Z
cd_dir/dir1/C
cd_dir/dir1/B
cd_dir/dir1/A

Note: files 'X' and 'Z' both have the weight 1000 - their sort order will then be the normal ISO9660 sort order (i.e. alphabetical in this case).

File C will have the default weight of 0

Warning: the filenames in the sort list MUST match the whole path as seen by mkisofs. i.e. in the above case, if the command line was:

mkisofs -o cdimage.iso -sort sort_file ./cd_dir

then the sort_file filename will have to changed as accordingly.

Notes

CDs are written from the middle outwards. High weighted files will be nearer the inside of the CD.

Wildcards in the filename list should work.

If a file appears more than once in the source directory tree, then the file is only added once to the CD image - i.e. a hard linked file, or symbolic link if using the -f option. The file will be sorted according to the highest weighting given to any of the linked files.

Zero length files are not sorted - the 'start extent' _may_ appear to be in the middle of another file after sorting. This is because zero length files are given the start extent after the last file added to the CD at that time. This address is not changed by the sorting, so it may appear that the file address is in another file - however as they are zero length, this will not matter==

Directories are not sorted by this flag - directories HAVE to be in the ISO9660 sort order - however, the files the directory entry points to, can be anywhere on the CD.

Existing files from any previous sessions will not be sorted - they already exist on the CD and can not be moved==

I have no idea if this is really useful ...

James Pearson 22-Nov-2001

Any comments/problems to j.pearson@ge.ucl.ac.uk

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