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pre-formed track spiral, which the recording laser
beam will follow when inscribing information onto the
disc. This type of disc is therefore called pre-grooved.
A translucent green or gold layer of recording material
(organic dye) is laid on top of the polycarbonate, then
a reflective layer of gold (hence the name “Gold
Disc”). The usual layers of lacquer and label are ap-
plied.
Green Book The Philips/Sony specification for CD-
Interactive (CD-I)
Hard Disk A magnetic storage medium for digital da-
ta. Also called a fixed disk or Winchester disk (“Drive”
may be appended to any of these names).
Header Field Four bytes recorded at the beginning of
each CD-ROM sector which tell the address of the sec-
tor (expressed as a Logical Block Number) and the
mode in which the sector is recorded.
High Sierra Format The original logical file format
for CD-ROM proposed by the High Sierra; still being
used by some CD-ROM publishers, although the
ISO9660 logical file format is the industry standard to-
day.
High Sierra Group The original group of twelve
companies which met in 1985 to define a standard log-
ical file format for CD-ROM. The group met at the
High Sierra Hotel near Tahoe, hence the name “High
Sierra”.
Hybrid Disc A disc as defined in the Orange Book de-
veloped by Philips and Sony; such a disc may contain
information written over more than one recording ses-
sion. Used with Kodak’s Photo CD. Hybrid is also a
generic term used to describe a disc with both
ISO9660 and Macintosh HFS or UNIX data structures.
IDE Intelligent Drive Electronics. IDE has been the
Glossary
