M2488 PRODUCT GUIDE TAPE UNIT SCSI COMMANDS
April 1997 CG00000-011503 REV. A 4-33
4-3.10 LOG SENSE command 4Dh
The LOG SENSE Command provides a means for the initiator to retrieve statistical information
maintained by the target about itself and attached logical units. It is a complementary command to
the LOG SELECT command. Log data is collected within the target on a per event basi s regardless of
the initiator ID.
4-3.10.1 LOG SENSE CDB De scription
LOG SENSE is a ten-byte command. The bytes are shown below and described in Table 4-34.
Common fields are described in paragraph 4-3.1 on page 4-4.
BITS
BYTES 7 6 5 4 3 2 1 0
00 1 0 0 1 1 0 1
1LUN Reserved PPC=0b 0
2PC=01b Page Code
3Reserved
4Reserved
5MSB Parameter Pointer
6LSB
7MSB Allocation Length
8LSB
9Reserved Flag Link
Note: Changeable fields in the CDB are shaded.
Table 4-30. LOG SENSE Field Description
BYTE BIT VALUE DESCRIPTION
0 0-7 4Dh Operation code.
1 1 0b The Parameter Pointer Control (PPC) bit controls the type of parameters
requested from the target. The PPC bit must be zero indicating that the log
parameter requested from the target shall begin with the parameter code specified
in the Parameter Pointer field and return the number of bytes specified by the
Allocation Length field in ascending order of parameter codes from the specified
log page. A PPC bit of zero and a Parameter Pointer field of zero shall cause all
available log parameters for the specified log page to be returned to the initiator
subject to the specified allocation length.
2 0-5 The Page Code field identifies which page of data is being requested. The page
codes are described in Table 4-31.
2 6-7 01b A Page Control field (PC) of 01b must be specified to indicate that the target’s
current cumulative counter values for the specified log pages are returned.