Image Number 7 for United States Patent #4413328.
In a storage subsystem employing removable record media such as contained in a cartridge, each storage recorder has a multidigit alphanumeric display located immediately above a cartridge receiver. The symbols on the display are arranged to be aligned with the symbols on the cartridge when inserted into recorder so that visual correlation is facilitated. Each recorder has a microprocessor which controls the display in response to host supplied LOAD DISPLAY commands. Each command includes a cartridge identification field for displaying on the display for such verification as well as orders for setting up display modes and display sequencing. The recorder microprocessor will display status of the recorder in response to a control field of the LOAD DISPLAY message at predetermined drive states, display a cartridge number after a cartridge has been removed from the recorder (i.e., the number of the cartridge to be inserted), inhibit a recorder status message or error message until the recorder is READY, i.e., until the recorder is communicating with a control unit; and to selectively supply cartridge numbers of the cartridge in the recorder and a next cartridge to be inserted for effecting a cartridge exchange.