CD-ROM Discs: Joliet & Romeo Name Definitions

When creating compact discs using CD-R drives, you may encounter the names Joliet and Romeo. This article discusses these file naming conventions noting the implications for Apple DOS and PC Compatibility cards.
This article has been archived and is no longer updated by Apple.
After the release of Windows 95, Microsoft developed two variations of the ISO-9660 format, named Romeo and Joliet.

Joliet File-Naming Convention

When you choose Joliet, two file lists are maintained on the compact disc. The first file list is for long Windows 95 filenames (up to 64 characters). The second file list is for DOS-compatible filenames that are truncated from the Windows 95 filenames. The way this works for the second file list is that the first six or seven letters of each long filename are used, with the tilde(~) added at the end. A unique number appears after the tilde to prevent duplicate filenames.

Romeo File-Naming Convention

The Romeo file naming convention is used only on Windows 95 or Windows NT computers. Do not use Romeo if you want to read the compact disc on operating systems other than Windows 95 or Windows NT. When you choose Romeo file naming convention during the writing of a CD session, only one file list is maintained on each CD. The Romeo file naming convention uses long Windows filenames (up to 128 characters).

Romeo Format Compatibility

The Romeo format is not currently compatible with the PC and DOS Compatibility Cards. Most Joliet formatted CD-ROM discs are compatible provided the programs used recognize the second short-name file list that was created.

PC Compatibility Cards and CD-ROM Disc Support

ISO-9660 Only: Apple PC Compatibility cards were designed to support only the ISO-9660 CD-ROM format. Whether a particular driver is 16-bit or 32-bit is irrelevant.

No Apple Update for Romeo and Joliet: There will probably not be an Apple update for Romeo compatibility or for Joliet CD-ROM discs that do not function correctly. If Romeo and Joliet were incorporated into an ISO standard, then it is possible that a Mac OS CD-ROM driver could allow these discs to work. Microsoft would have to submit these as standards, they would have to be accepted, and then a CD-ROM driver vendor (or Apple) would need to update their software to accommodate the new standard.

Real Mode (16-bit) versus Protected Mode (32-bit): The PC Compatibility cards all access the drives (floppy, CD-ROM, and hard drive) in Real or DOS Compatibility Mode. There are some programs (usually programs that are Windows 95-only) that require Protected Mode drivers. Unless these programs have a Real Mode compatible version, they will not work with the PC Compatibility cards. Apple has no plans at this time for Protected Mode drivers for the PC Compatibility cards.

Using Incompatible CD-ROM discs: For CD-ROM discs that are neither Romeo or Joliet or ISO-9660, you may be able to set them up as shared drive in PC Setup. An example of this would be a CD-ROM disc recorded as a High Sierra format disc (the precursor to ISO-9660). Mac OS can read this format. Anything that Mac OS can read should be able to be mounted as a shared disc.
Published Date: Feb 20, 2012