This is a list of SCSI message codes.
A SCSI message code is a computer term which defines how SCSI devices send interface management information. The message code comprises one or more bytes.
List of message formats
editThe first byte of the message determines the format:
| Value | Message format |
|---|---|
| 00h | One-byte message (COMMAND COMPLETE) |
| 01h | Extended messages |
| 02h-1Fh | One-byte messages |
| 20h-2Fh | Two-byte messages |
| 30h-7Fh | Reserved |
| 80h-FFh | One-byte message (IDENTIFY) |
List of message codes
edit| Value | Message name | Format |
|---|---|---|
| 00h | COMMAND COMPLETE | |
| 01h | EXTENDED MESSAGE | 01nnyy... - nn is the length, yy is the extended message code |
| 02h | SAVE DATA POINTER | |
| 03h | RESTORE POINTERS | |
| 04h | DISCONNECT | |
| 05h | INITIATOR DETECTED ERROR | |
| 06h | ABORT | |
| 07h | MESSAGE REJECT | |
| 08h | NO OPERATION | |
| 09h | MESSAGE PARITY ERROR | |
| 0Ah | LINKED COMMAND COMPLETE | |
| 0Bh | LINKED COMMAND COMPLETE (WITH FLAG) | |
| 0Ch | BUS DEVICE RESET | |
| 0Dh | ABORT TAG | |
| 0Eh | CLEAR QUEUE | |
| 0Fh | INITIATE RECOVERY | |
| 10h | RELEASE RECOVERY | |
| 11h | TERMINATE I/O PROCESS | |
| 12h-1Fh | Reserved | |
| 20h | SIMPLE QUEUE TAG | 20nn - where nn is the queue tag |
| 21h | HEAD OF QUEUE TAG | 21nn - where nn is the queue tag |
| 22h | ORDERED QUEUE TAG | 22nn - where nn is the queue tag |
| 23h | IGNORE WIDE RESIDUE | 230i - where i is the number of bytes to ignore (can be 1, 2 or 3) |
| 24h-2Fh | Reserved for two-byte messages | |
| 30h-7Fh | Reserved | |
| 80h-FFh | IDENTIFY |
List of extended message codes
edit| Value | Length | Message name | Format |
|---|---|---|---|
| 00h | 05h | MODIFY DATA POINTER | 010500aaaa - where aaaa is added to the current data pointer |
| 01h | 03h | SYNCHRONOUS DATA TRANSFER REQUEST | 010301pprr - where pp is the period and rr is the REQ/ACK offset |
| 02h | nn | Reserved - was formerly used for the EXTENDED IDENTIFY message in SCSI-1 | 01nn02... |
| 03h | 02h | WIDE DATA TRANSFER REQUEST | 010203ee - where ee is the transfer width exponent |
| 04h-7Fh | Reserved | ||
| 80h-FFh | Vendor-specific |