Hi Terry, TempleOS has some really interesting concepts. I'm not sure what it has to do with this topic though. FILE_ID.DIZ is used for archives and not single files, and is used to provide metadata for the contents of the archive.

Saving disk space by compressing and decompressing files on the fly by appending a .Z file extension works, but the compression efficiency for individual files must be less than if you were using a compressed volume from the beginning. Compressing each file individually can't take advantage of common tokens between similar files.

Anyway, thanks for commenting, but I fail to see the correlation and the point you're trying to make. Again, FILE_ID.DIZ is about providing a standardized way of finding out about the contents of an archive, (which I suppose could just have one file, aside from the description file,) and so it isn't really relevant to how TempleOS compresses individual files.