zisofs is an extension of ISO 9660 format, which adds support for per-file compression.
It is designed as an extension of Rock Ridge. It specifies a new entry, with signature "
For the apparent predecessor of zisofs, see Isofs transparent compression.
zisofs-compressed files use a special format, with signature bytes
37 e4 53 96 c9 db d6 07. Files in this format could be visible if zisofs is not supported, or as part of some workflows for creating a zisofs volume.