Abstract: A library apparatus where multiple moving commands generated by several upper-order units are conveyed to a director. The moving commands may be sequentially conveyed through the same channel or may be simultaneously conveyed through different channels. The moving commands are then conveyed to an accessor controller which includes a real table and a plurality of virtual tables. The contents of one of the virtual tables is switched to the real table. Accessors are operative in accordance with the contents of the real table. The switching of contents from virtual tables to the real table enables the accessor controller to act as if two operation commands exist instead of one command so that a plurality of accessors can operate simultaneously.

Abstract: A library apparatus where multiple moving commands generated by several upper-order units are conveyed to a director. The moving commands may be sequentially conveyed through the same channel or may be simultaneously conveyed through different channels. The moving commands are then conveyed to an accessor controller which includes a queuing table for storing the commands. The queuing table permits the accessor controller to receive additional commands prior to the execution of the previous command. Therefore, the processing speed of the system is increased. Next, the commands are conveyed to a plurality of accessors which transfer the medium cartridges to the desired location. Several accessors may be operated simultaneously in parallel. The simultaneous operation of several accessors also increases the efficiency and speed of the system.

Abstract: A library apparatus where multiple moving commands generated by several upper-order units are conveyed to a director. The moving commands may be sequentially conveyed through the same channel or may be simultaneously conveyed through different channels. The moving commands are then conveyed to an accessor controller which includes a queuing table for storing the commands. The queuing table permits the accessor controller to receive additional commands prior to the execution of the previous command. Therefore, the processing speed of the system is increased. Next, the commands are conveyed to a plurality of accessors which transfer the medium cartridges to the desired location. Several accessors may be operated simultaneously in parallel. The simultaneous operation of several accessors also increases the efficiency and speed of the system.