
Example PlayStation Disc Layout

Blocks          Description
------          ------------
000000-000015   Data track boot blocks        (see NOTE 1)
000016-024520   Data track program area       (see NOTE 2)
024521-024670   Postgap for data track        (see NOTE 3)
024671-024820   Pregap for first audio track  (see NOTE 4)
024821-048326   Audio track #1
048327-048476   Pregap for second audio track (see NOTE 5)
048477-072485   Audio track #2
      .
      .
      .
191281-191430   Pregap for ninth audio track
191431-214349   Audio track #9
214350-??????   Leadout Track (see Note 4)


NOTE 1: The first sixteen blocks of a PSX discs are the "boot" blocks.
They contain some territory information, but I don't know if this is
the actual data that is used by the "territory lockout" code.

NOTE 2: The rest of the data track is where the actual program (game)
is stored. The track is encoded in CDROM-XA format using both Form-1
and Form-2 sectors. The file system is in ISO9660 format.

NOTE 3: When any data track is followed by an audio track, it must
end with a postgap of at least 150 sectors. On all of the PSX discs
that I have analyzed, this postgap is composed of 150 sectors of
zeroed data. The purpose of the postgap is to provide a "buffer zone"
between the real data in the track and the subsequent audio track.
Some CD readers can't read the last few blocks of a track if they are
followed by audio sectors.

NOTE 4: When an audio track follows a data track, it must start with
a pregap of at least 150 sectors. On the PSX discs that I have analyzed,
I have seen pregaps of both 150 (2 secconds) and 300 sectors (4 seconds).
This pregap serves the same purpose as the data postgap... to physically
separate the data and audio sectors to avoid reading errors (data and
audio sectors are usually read with separate commands and each command
can only read a specific sector type).

NOTE 5: The pre-gap for all audio tracks after track #1 seems to be
150 sectors for all PSX discs.

NOTE 4: The LEADOUT track is written by the recorder automatically
(except for the Philips) and is not under user control. It is not
possible to read this area of the disc with a normal CDROM reader
or recorder.


