Tandberg Data
Chapter 3 - Operation
Autoloader Operation Modes
The autoloader has two operating modes, random mode and sequential mode.
Random mode is the factory default operation mode.
Random Mode
When the loader is operating in random mode, the host computer controls the drive
and the loader robotics individualy through two separate SCSI Id’s. The host can
move cartridges around between magazine slots and between the magazine and the
drive.
Sequential Mode
The purpose of sequential mode is to emulate operator assisted backup over multiple
tapes. When one tape is full and unloaded by the host, the loader robotics will
automaticly replace it with the next cartridge in the cartridge set. This feature can
allow users with single drive backup systems to replace the drive with a loader and
automate their backup routines.
In sequential mode the loader operates with sets of cartridges. A cartridge set,
consist of all cartridges starting with the first cartridge in the magazine or the first
cartridge after an empty magazine slot. The set is ending with the last cartridge in
the magazine or with a cartridge in front of an empty magazine slot.
Example: If the magazine has cartridges in slot 1, 2 and 3 and in slots 5, 6, 7 and 8,
the magazine contains two cartridge sets separated by the empty slot 4.
A full magazine contains one set of 8 cartridges. (7 cartridges if the Cleaning slot is
enabled.)
When the loader is set in Sequential mode, the host can only control the tape drive.
The loader will respond normally to an Inquiry and a Request Sense command, but
will return a check condition on all media changer type commands. The Sense Key
will be set to 02h (Not Ready) and the Asc / Ascq will be 04h/8Eh (Logical unit Not
Ready, Sequential mode).
Chapter 4 – Configuration.
describes how the loader can be set in sequential mode.
The Sequential mode has two sub modes, normal or recirculate sequential mode.
Tandberg SLR Autoloader Service and Repair Manual
35