Apple ISO 9660 Extensions  Apple has a set of ISO 9660 Extensions that extends the filesystem with ProDOS or HFS properties. The primary file system for Apple Macintosh computers is HFS (or HFS+). The HFS file system has more properties than FAT file systems (which are primarily used on Windows 95 and 98 operating systems). Some of the metadata properties include:  In order to allow non-Macintosh systems to access Macintosh files on CD-ROMs, Apple chose to use an extension of the standard ISO 9660 format. Most of the data, other than the Apple specific metadata, remains visible to operating systems that are able to read ISO 9660.