Operating instructions

3-4
SCSI REFERENCE 1012975
CHAPTER 3—IMPLEMENTING SCSI OPERATIONS
3.4 UNDERSTANDING THE CARTRIDGE INVENTORY
The autoloader maintains a cartridge inventory in volatile memory. The
inventory is automatically re-established whenever the autoloader is powered
on or whenever the cartridge access port door is opened, then closed again.
The inventory contains information about the following element locations:
 Medium transport element (the carousel/cartridge loader)
 Storage elements (the seven cartridge cells)
 Data transfer element (the tape drive)
The autoloader uses the information stored in the cartridge inventory to
process SCSI commands.
3.4.1 ESTABLISHING THE CARTRIDGE INVENTORY
The autoloader automatically updates the cartridge inventory when it is
powered on or whenever the cartridge access port door is opened, then closed
again. You can use the INITIALIZE ELEMENT STATUS (07h) or INITIALIZE
ELEMENT STATUS WITH RANGE (E7h) command to attempt reading a bar
code label that could not be read during the most current cartridge inventory
operation.
3.4.2 RETRIEVING CARTRIDGE INVENTORY INFORMATION
After the current cartridge inventory has been determined using an
INITIALIZE ELEMENT STATUS command, you can retrieve the inventory
information by issuing a READ ELEMENT STATUS (B8h) command (see
Chapter 15).
3.4.3 TYPES OF INFORMATION STORED IN THE CARTRIDGE
I
NVENTORY
As described in this section, the cartridge inventory contains the following
information for every element location:
 Element address
 Element occupied status
 Bar code label information
 SCSI element reservation information
 Tape drive accessible status
 Cartridge pick and put (place) retry counts
 Total number of cartridge picks and puts (places)
 Source element address