Quantum Audio Travan 40 Tape Drive STT3401A - Manual (Page 43)

ATAPI Interface Chapter 5
Seagate Travan 40 Product Manual Page 35
LOCATE (Group 1, Op. Code 2B)
The LOCATE command causes the target to position the logical unit to the specified
block address in a specified partition. Upon completion, the logical position will be
before the specified location so that the specified block will be the next to be read, or
will be the append point if it follows an “Appendable Point” (see WRITE command).
Prior to performing the locate operation, the target shall ensure that all buffered data
and filemarks have been transferred to the media.
If the specified block is not found in the current partition, then a Check Condition
status is returned, the Sense Key is set to Blank Check (8h), the BNL bit is set in
byte 12h of the Sense Data, and the tape will be positioned at EOD.
CDB for LOCATE Command
Data Bits
Byte 7 6 5 4 3 2 1 0 Hex
0 0 0 1 0 1 0 1 1 2B
1 0 0 0 0 0 0 CP 0 0X
2 0 0 0 0 0 0 0 0 00
3
4
5
6 MSB
Block Address
LSB
XX
XX
XX
XX
7 0 0 0 0 0 0 0 0 00
8 Partition XX
9 0 0 0 0 0 0 0 0 00
CP: The Change Partition bit determines if a partition change is required before
positioning to the requested block. When set to 1, the partition specified in the
Partition field is selected. If necessary, the drive will change partitions before
positioning to the requested block. This is only allowed if the FDP bit in the Media
Partition Page (MODE SENSE Page 11h) has been set to 1. A CP bit of 0 indicates
no partition change required. The partition field is ignored.
Block Address: The Block Address field specifies the logical block address at which
the target shall be located.
Partition: The Partition field specifies which partition to select (if the CP bit is 1).
When set to 0, the Data Partition is selected. When set to 1, the Directory Partition is
selected.
Application Notes:
The CP field is one of two methods to change the active partition between the Data
and Directory Partitions. The second method is to use the Device Configuration Page
of the MODE SELECT command.
The Travan 40 format specifies that there will always be two partitions physically on
the tape.