Filter
Top Products
M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-51
4-3.12 MODE SELECT command 15h
The MODE SELECT command provides a means for the initiator to specify medium, logical unit,
and peripheral device parameters to the target by sending data relevant to such parameters in a
DATA OUT phase during the command. Initiators should issue MODE SENSE prior to MODE
SELECT to determine supported pages, page lengths, and other parameters. A single set of MODE
SELECT parameters kept by the controller is common to all initiators for a specific LUN. The
MODE SELECT command can be completed without error whether or not the LUN is ready. Buff-
ered write data is synchronized to tape prior to activating the new mode parameters.
4-3.12.1 MODE SELECT CDB Description
MODE SELECT is a six-byte command. The bytes are shown below and described in Table 4-42.
Common fields are described in paragraph 4-3.1 on page 4-4
.
The Unit Attention/Mode Parameters Changed sense data will be reported to other initiators after a
Mode Select command if and only if the setting of at least one parameter was actually changed
from its previous setting. Therefore, issuing a Mode Select command with parameters that are the
BITS
BYTES 7 6 5 4 3 2 1 0
0
0 0 0 1 0 1 0 1
1
LUN PF Reserved SP
2
Reserved
3
Reserved
4
Parameter List Length
5
Reserved Flag Link
Note: Changeable fields in the CDB are shaded.
Table 4-42. MODE SELECT Field Description
BYTE BIT
VALU
E
DESCRIPTION
0 0-7 15h Operation Code.
1 0 0
1
A Save Pages (SP) bit of zero indicates the target shall perform the specified MODE
SELECT operation, and shall not save any pages in non-volatile memory.
A SP bit of one indicates that the target shall perform the specified MODE SELECT
operation, and shall save to a non-volatile location all the savable pages sent during
the DATA OUT phase.
1 4 0 or 1 A PF (Page Format) bit of 0 or 1 both indicate that the MODE SELECT parameters
are structured as pages of related parameters as defined by the ANSI standard.
4 0-7 The Parameter List Length field specifies the length in bytes of the MODE SELECT
parameter list to be transferred from the initiator to the target. A parameter list length
of zero indicates that no data is transferred. This condition is not considered an error.