Quantum 10K II Manual de usuario descargar pdf (Pagina 346)

Appendix B. SCSI Bus Signal Timing

Quantum Atlas 10K II Ultra 160/m SCSI Hard Disk Drives B–25

B.7 SCSI MESSAGE FORMAT

A message can be one or more bytes in length. One or more messages can be sent

during a single MESSAGE phase, but a message cannot be split over MESSAGE

phases. The initiator is required to end the MESSAGE OUT phase (by negating

ATN) when it sends certain messages.

A message cannot be split. The drive will not split messages longer than one byte

even if ATN is deasserted.

When a connection to the drive is established (i.e., the drive is selected with ATN

asserted), the first message byte passed by the initiator must be either an

IDENTIFY, ABORT TASK SET, or TARGET RESET message. If not, the drive

discards the message, saves no status information, and goes to the BUS FREE

phase.

If an initiator supplies an unsupported or incorrect messages (for example, TASK

COMPLETE, or a reserved or undefined message code), the drive returns a

MESSAGE REJECT message and continues where it left off (possibly returning to

MESSAGE OUT if ATN is raised).

The first byte of the message, as defined in Table B-10, gives the format of the

message.

Table B–10 SCSI Message Format

Message Code Message

00h One-byte message (TASK COMPLETE)

01h Extended message

02h − 1Fh One-byte message

30h − 7Fh Reserved

80h − FFh One-byte message (IDENTIFY)

The drive supports the messages listed in Table B-11. The message code and the

direction of the message flow is also included in the table.

1 2 ... 341 342 343 344 345 346 347 348 349 350 351 ... 370 371

Sin comentarios

Quantum 10K II Manual de usuario Pagina 346