Quantum 10K II - Manual (Page 348)

Appendix B. SCSI Bus Signal Timing
Quantum Atlas 10K II Ultra 160/m SCSI Hard Disk Drives B–27
Bit 7 6 5 4 3 2 1 0
Byte
0 Extended Message (01h)
1 Extended Message length
2 Extended Message code
3
to Extended Message Arguments
n-1
Figure B–1 Extended Message — Data Format
Table B–12 Extended Message — Field Description
Field Description
Extended Message Length This field specifies the length, in bytes, of the Extended
Message Code plus the Extended Message Arguments that
follow. Therefore, the total length of the message is equal to
the Extended Message Length plus 2.
A value of 0 for the Extended Message Length indicates that
256 bytes follow.
Extended Message Code The drive supports three Extended Messages. They are:
01h SYNCHRONOUS DATA TRANSFER REQUEST
03h WIDE DATA TRANSFER REQUEST
04h PARALLEL PROTOCOL REQUEST