Patent GB-847961-A (GB)
Title: Transfer and storage of digital data signals
IPC: G06F3/08
Filed: 1957-11-06
Abstract: 847,961. Magnetic drum data-storage apparatus. DIRKS, G. Oct. 10, 1958 [Nov. 6, 1957], No. 34549/57. Class 106 (1). Data sensed from the 80 columns (horizontal in Fig. 1) of a punched card 1 is recorded in serial form on data track 11 of a magnetic storage drum which makes five complete revolutions during the reading of the card, the data being recorded interlaced in sixteen sectors on the drum (the characters from five columns, e.g. columns 80, 64, 48, 32 and 16, being recorded in a single sector) so that a buffer store for a single character only is required, this being provided by gas-filled valves 15/1-8 and 21/1-4. Fig. 2 shows two sectors of each of the tracks, each sector of track 11 consists of four " digit " subsectors 23, 24, 25 and 25a for recording values 1, 2, 4 and 8 respectively of the binary-coded decimal signals obtained from card-recoder 13, and four " zone " sub-sectors used in entering alphabetic characters &c. Each sub-sector has five bit positions, the first-read column (column 80) of card 1 being entered into the first positions of the sub-sectors in sector I, the column 79 into the first positions in sector II and so on until column 64 is reached, when the drum begins its second revolution and the second positions in sector I are used. Clock pulses in the various positions of the sub-sectors are recorded in tracks 29/1-29/5; these are used for serializing the outputs of recoder 13 by the use of counters and gates shown in Fig. 1. Reading from left to right, the holes in the card 1 correspond to digit values 9-1 (sensed by photo-cells 3/1-3/9), digit value 0 (photo-cell 3/10), and " X " and " Y " positions (photocells 3/11, 3/12). An alphabetic character is indicated by a hole in one of the " 9-1 " positions in combination with a hole in the " O," "X " or " Y " position, a gate 20 ensuring that the output of photo-cell 3/10 only passes to the record head 12 when it occurs simultaneously with one of the digit values 9-1; the " O," " X " and " Y " outputs are recorded in the first three zone sub-sectors (designated zone values 1, 2 and 4). The arrival of the leading edge of a card interrupts the light to photo-cell 37 to switch monostable flip-flop 38 and open gate 39 so that the next pulse from track 41 (indicating the arrival of sector I, see Fig. 2) sets flip-flop 42 for the duration of a card sensing operation and so opens gates 46, 47 and 49. Gate 46 allows clock pulses from one of the tracks 29/1-5 to pass via line 45 to record gate 18; the selection of the appropriate clock track through gates 44/1-5 is effected by a five-stage ring counter 43 receiving pulses through gate 47 from track 41 to advance the count at each drum revolution, and at the end of five revolutions of the drum the count will return to stage 48, and gate 49 being open flipflop 42 is reset, closing the record gate 18. The opening of gate 18 in accordance with data to be recorded in each sector is effected by firing of gas-filled valves 15/1-8 and 21/1-4 corresponding to binary-coded decimal digits and O, X and Y (" zone ") values, and opening of gates 16/1-8 and 22/1-4 successively for one sub-sector period each by a scale-of-eight counter 50 (receiving clock pulses from track 29/1) and decoder 51 (in the eighth subsector period none of the gates 16, 22 is open and in this period valves 15 and 21 are de-ionized ready for registration of the next column data). Fig. 4 (not shown) illustrates a modification in which a single clock track 29 effects the recording, and the five different recording positions in each sub-sector are obtained by the use of five spaced recording heads in place of the head 12, selection of the appropriate head being made by the counter 43. It is stated that the magnetic drum may be replaced by are-circulating delayline store, and that recoder 13 may also calculate a parity check bit for each digit, or the checking arrangement described in Specification 832,011 may be employed.