Quantum Audio STT2401A ユーザーズマニュアル

ページ / 137
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 
Hex 
2B 
CP 
0X 
00 



MSB 
Block Address 
 
LSB 
XX 
XX 
XX 
XX 
00 
Partition 
XX 
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.