Chapter 4 SCSI Commands
MODE SENSE (6) / (10) Command (1Ah / 5Ah)
DLT-S4 Interface Reference Guide
157
MODE SENSE (6) / (10) Command (1Ah / 5Ah)
4
The
MODE SENSE
command allows the tape drive to report its media type
and current—or changeable—configuration parameters to the host. It is a
complementary command to
MODE SELECT
.
Figure 80
shows the CDB for the 6-byte
MODE SENSE
(1Ah) command.
An illustration of the CDB for the 10-byte
MODE SENSE
(5Ah) command
is shown in
figure 81
.
Figure 80
MODE SENSE
(6)
Command Descriptor Block —
Data Format
The 10-byte
MODE SENSE
command is required to request the vendor-
specific EEPROM parameter page due to the large amount of data that
parameter page contains.
MODE SENSE
(10) can be used to retrieve the
other pages as well. Note that
MODE SENSE
(10) returns descriptor data
in a different format than
MODE SENSE
(6).
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code (1Ah)
1
Reserved
DBD
Reserved
2
PC
Page Code
3
SubPage Code
4
Allocation Length
5
Control
Note:
The drive returns a
CHECK CONDITION
status with Sense Key
set to
ILLEGAL REQUEST
if it receives an unsupported Page
Code or a Page field with values not supported or not
changeable. In such cases, the drive does not change any
parameters as a result of the command.