The TDS cannot require any particular restriction on filenames in the tree, since the names of many existing TEX files conform to no particular scheme. For the benefit of people who wish to make a portable TEX distribution or installation, however, we outline here the necessary restrictions.
It turns out that ISO-9660 meets the stringent limitations of all operating systems in use today. It is the only universally acceptable file system format for CD-ROMs. It specifies the following:
Some systems display a modified format of ISO-9660 names, mapping alphabetic characters to lowercase, removing version numbers and trailing periods, etc.