[There may be an error between the ATIME value of the subcode Q channel and the sector address in the header. Therefore, when specifying the sector, the header value is used instead of the subcode Q channel.

Table 2.2 Header field layout

byte subscript	value
12 13 14 15	minutes seconds frames Mode

(1) File number

∙ File number is used to identify sectors belonging to one file. Some files can be recorded interleaved with other files. At this time, the file number of each sector of the logical file becomes the same value.
∙ File number can be used to select sectors belonging to the same file or to exclude non-target files.

The following restrictions apply depending on the file number value.

Table 2.3 File number restrictions

File number	Description
0	Used for the following files or areas -Files recorded continuously on the disc ・ Directory ・ Others (path table, volume descriptor) Cannot interleave with other files
1-255	Can be interleaved or continuous (with other files It ’s not clear if it ’s interleaved or not.)