Fujitsu M2488 manual Rewind command 01h, Rewind CDB Description, Rewind Field Description

M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS

4-3.26 REWIND command 01h

The REWIND command causes the logical unit to position to the beginning of tape. Any buffered write data and filemarks are written to the tape before the positioning is performed.

A single REWIND command may not actually cause the tape head to be physically positioned at the beginning of the tape; positioning may occur only in the buffer or the tape head may be physically positioned just before the first block but after the Density ID mark on the tape. Issuing two consecu- tive REWIND commands forces the logical unit to position the tape head at the physical beginning of tape. (This may prove useful for test purposes; e.g. The Density ID mark will always be read for a Read command following two consecutive REWIND commands.

4-3.26.1 REWIND CDB Description

REWIND is a six-byte command. The bytes are as shown below and described in Table 4-106. Common fields are described in paragraph 4-3.1 on page 4-4.

						BITS
BYTES	7	6	5		4		3		2	1		0
0	0	0	0		0		0		0	0		1
1
		LUN						Reserved					Immed
2						Reserved
3						Reserved
4						Reserved
5
				Reserved							Flag			Link

Note: Changeable fields in the CDB are shaded.

Table 4-106. REWIND Field Description

BYTE	BIT	VALUE	DESCRIPTION
0	0-7	01h	Operation code for the rewind command.
1	0	0	If the Immed (Immediate) bit is 0, Status is not returned for the REWIND
			command until the rewind has completed or has failed.
		1	If the Immed (Immediate) bit is 1, Status is returned for the REWIND
			command as soon as the CDB has been validated and any buffered write
			data and filemarks have been written to tape. The rewind operation has
			been started but not necessarily completed when status is returned.

4-3.26.2 REWIND CHECK CONDITION Status

If the status reported for the previous command was a CHECK CONDITION because data could not be written to the tape, then any buffered data is discarded before the rewind occurs.

If CHECK CONDITION status is reported for a REWIND command with the Immediate bit set to 1, then the rewind will not occur.

April 1997 CG00000-011503 REV. A 4-115