#USGS CD-ROM
You are referring to ISO-9660, a standard version of the original
High Sierra format. It is used to provide compatibility across
platforms -MSDOS, MAC, UNIX, VMS, AMIGA, etc. Virtually all CD-ROM
driver software supports it. The standard addresses things like
directory structure, file name lengths (kept down to 8 chars and 3
char extension due to MS-DOS limits), etc.
Where did you get the catalog (address/phone/fax #)?