Random and Random 2-LUN Modes
Random mode is designed to act as a small,
Random
Random mode is supported only on Model B1A. Random
Being in Random mode does not preclude attaching host requests for specific mounts. Requests for specific cartridges to be mounted can be satisfied by inserting the specific cartridge in the priority cell. In Random mode, the priority cell is simply another addressable cell. The ACF notifies the attaching host of the presence of a cartridge in the priority cell. However, the attaching host must specifically address that cell to access the cartridge.
To ensure the integrity of the library, the magazine has a lock on the magazine. The magazine lock prevents the addition or removal of cartridges from the magazine after the magazine is installed in the ACF and locked. The ACF senses the state of the magazine lock. It does not permit Random mode to be enabled unless the magazine lock is set to the locked position. A sensor on the ACF allows the unit to determine that the magazine is not installed or that it was removed. This disables Random mode.
Because the magazine must be locked in Random mode, the priority cell is used as an I/O port to the library. In this mode, it will add or remove cartridges from the magazine without having to violate the integrity of the locked magazine. The attaching host can move cartridges from the priority cell to any empty magazine cell (or the device). It can also move cartridges from a magazine cell (or the device) to the priority cell. Library inventory and the control of the inventory are entirely the responsibility of the attaching host.
If a Move Medium or Read Element Status command is issued, with no magazine present, or with the magazine unlocked, the command fails with a permanent error.
When the ACF is in Random mode, the following applies (see also “ACF Notes” on page 56):
vInitial conditions
