GB1320521A - Storage and retrieval control apparatus and method - Google Patents

Abstract

1320521 Juke box WURLITZER CO 29 April 1970 20637/70 Heading G5R In apparatus for controlling access to an array of information carrying members, e.g. records or tape cassettes in juke boxes or reels of microfilm, the number of the member selected by pushbutton is initally stored as a number in one or more flip-flop buffer stores from which it is transferred first to an end-around shift register where the number is stored as a position in the register and thence to a further store in which the number is compared with that in a counter fed with pulses generated as scanning means scan the member array to stop the scanning process at the selected member when the numbers coincide. In the juke box arrangement described access is arranged at a main or a number of remote points at which selection apparatus 16, 24, is readied when a credit indication is received from a coin-operated credit accumulator 20, 21. Selection is by alpha-numeric push-button and appears as a number stored in a flip-flop buffer store at the selection point. The presence of a selection at a remote point is detected by scanner 18 via which the number selected is transferred by counter and comparison means to a further buffer store associated with control unit 14. The control unit acts to gate the number in the further store or that in the buffer store at the main selection point to a main input buffer store in the storage and read-out unit 12. In this unit clock pulses are fed to an endaround shift register and to a pair of counters. When the count in one of the counters agrees with the number in the input buffer store the end flip-flop in the register is marked but the feed of clock pulses is continued until the register returns to its initial position and the counters to zero. By this means the number is stored as the position of the marked flip-flop in the register. When an output buffer store is free the clock pulses are again applied to the register and counters and when the marked stage reaches an end of the register a signal is generated which transfers the count in one of the counters to this output buffer stage. The scanning process is now commenced and by comparison stages the number is compared with that developed in a counter fed with a pulse each time a stored record is scanned, the process being stopped at the required record when the numbers agree.