IBM T200F manual Byte Mode Select Command

MODE SELECT

Table 26. Byte MODE SELECT Command

	7	6	5		4		3	2	1	0
0				Operation Code (15h)
1	Logical Unit Number (0)				PF			Reserved		SP(0)
2					Reserved
3					Reserved
4				Parameter List Length
5						Control
Table 27. Byte MODE SELECT Command
	7	6	5		4		3	2	1	0
0				Operation Code (55h)
1	Logical Unit Number (0)				PF			Reserved		SP(0)
2					Reserved
3					Reserved
4					Reserved
5					Reserved
6					Reserved
7				Parameter List Length
8
9						Control

Both the 10-byte and 6-byte versions of the MODE SELECT command are supported.

The MODE SELECT command causes configuration data to be sent to the drive. For the format of Mode data and supported Mode pages see “MODE SENSE” on page 27.

The Page Format (PF) flag may be any value. However, the drive assumes that the format is SCSI-2. The Save Pages (SP) flag must be set to 0, since saved pages are not supported. The Parameter List Length field should be set to the amount of data to be sent to the drive.

The maximum acceptable Parameter List Length for a SCSI parallel drive is 198 bytes, and the maximum acceptable Parameter List Length for a Fibre Channel drive is 222 bytes. Any command with a larger value results in a Check Condition status. The associated sense data returns with a Sense Key of Illegal Request and an ASC/ASCQ of Invalid Field in CDB (2400).

If any of the fields in the Mode pages are invalid, no parameters are altered, Check Condition status is returned, the Sense Key is set to Illegal Request, and the ASC/ASCQ is set to Invalid Field in Parameter List (2600).

26Ultrium Internal Tape Drive and 3580 Ultrium Tape Drive: SCSI Reference