CHAPTER 13

Table 13.16 CD File System Formats
CD-ROM File Systems Chapter 13
715
CD File System DOS/Win 3.1 Win 9x/Me Win NT/2000 Mac OS
High Sierra Yes Yes Yes Yes
ISO 9660 Yes Yes Yes Yes
Joliet Yes1 Yes Yes Yes 1
UDF No Yes2 Yes 2 Yes 2
1. A short name, such as (SHORTN~1.TXT), is shown.
2. Only if a UDF driver is installed.
Note
The Mac HFS and Rock Ridge file systems are not supported by PC operating systems such as DOS or Windows and
therefore are not covered in depth here.
High Sierra
To make CD-ROM discs readable on all systems without having to develop custom file systems and
drivers, it was in the best interests of all PC hardware and software manufacturers to resolve the CD-
ROM file format standardization issue. In 1985, representatives from TMS, DEC, Microsoft, Hitachi,
LaserData, Sony, Apple, Philips, 3M, Video Tools, Reference Technology, and Xebec met at what was
then called the High Sierra Hotel and Casino in Lake Tahoe, Nevada, to create a common logical format
and file structure for CD-ROMs. In 1986, they jointly published this standard as the “Working
Paper for Information Processing: Volume and File Structure of CD-ROM Optical Discs for
Information Exchange (1986).” This standard was subsequently referred to as the High Sierra format.
This agreement enabled all drives using the appropriate driver (such as MSCDEX.EXE supplied by
Microsoft with DOS) to read all High Sierra format discs, opening the way for the mass production
and acceptance of CD-ROM software publishing. Adoption of this standard also enabled disc publishers
to provide cross-platform support for their software, easily manufacturing discs for DOS, Unix, and
other operating system formats. Without this agreement, the maturation of the CD-ROM marketplace
would have taken years longer and the production of CD-ROM–based information would have been
stifled.
The High Sierra format was submitted to the International Organization for Standardization (ISO),
and two years later (in 1988) and with several enhancements and changes it was republished as the
ISO 9660 standard. ISO 9660 was not exactly the same as High Sierra, but all the drivers that would
read High Sierra–formatted discs were quickly updated to handle both ISO 9660 and the original High
Sierra format on which it was based.
For example, Microsoft wrote the MSCDEX.EXE (Microsoft CD-ROM extensions) driver in 1988 and
licensed it to CD-ROM hardware and software vendors to include with their products. It wasn’t until
1993 when MS-DOS 6.0 was released that MSCDEX was included with DOS as a standard feature.
MSCDEX enables DOS to read ISO 9660–formatted (and High Sierra–formatted) discs. This driver
works with the AT Attachment Packet Interface (ATAPI) or Advanced SCSI Programming Interface
(ASPI) hardware-level device driver that comes with the drive. Microsoft built ISO 9660 and Joliet file
system support directly into Windows 95 and later, with no additional drivers necessary.
ISO 9660
The ISO 9660 standard enabled full cross compatibility among different computer and operating systems.
ISO 9660 was released in 1988 and was based on the work done by the High Sierra group.