Patent GB-790523-A (GB)
Title: Improvements in or relating to electronic computing machines
Inventor: YANDELL RONALD PERCY BAWDEN
IPC: G06F3/08
Filed: 1955-12-14
Abstract: 790,523. Statistical apparatus. POWERSSAMAS ACCOUNTING MACHINES, Ltd. Nov. 9, 1956 [Dec. 14, 1955], No. 35935/55. Class 106 (1). Apparatus for controlling the input of digital data to a calculating machine comprises pinbox means for sensing a perforated record card during each machine cycle and to set-up mechanical elements controlling electrical contacts, a rotatable magnetic drum having writing means energizable by the record-controlled contacts and control means co-operating with these contacts and operable by pulses permanently recorded on the drum to control columnby-column writing into a storage track of the drum digital value representations. Card sensing.-The record card is of a conventional kind having eighty columns and twelve rows of hole positions. In each column there are positions 1-9 and three " overpunch " positions A, B, O, the latter positions being allotted values as described below (Fig. 7) by making connections on a plugboard PLU. As shown in Fig. 8 sensing is effected by a series of pins 34 one for each hole position mounted in a pin-box 35 which is lowered on to the card C held between perforated guide plates. Any pin registering with a hole is allowed to pass through so that its upper end clears the lower end of a cooperating hatchet pin 37 which is accordingly allowed to swing under the influence of spring 38 into the vertical position aligned with the sensing pin. The other pins are supported by the card and are prevented from clearing their hatchet pins. When the pin box is raised the pin that sensed a card hole lifts its hatchet pin 37 and thereby an associated contact rod 24 or 25 to engage contact 28. Rods 24 for positions 1-9 are connected to a contact strip 20 through springs 27 and rods 25 for the overpunch positions A, B, O, are connected to strip 21. Recording.-The stationary contacts 28 for positions 1-9 are connected together in rows by wires 30 as shown in Fig. 7 but the contacts 31 for the A, B, O positions have individual wires leading to plug board PLU. Column positions are connected through a recoding system of diodes and cathode followers CF to four lines CDO representing the value sensed in binary notation. Connections from the contacts for the A, B, O positions are made as desired to lines having values of from 1 to 11, these lines being connected to appropriate ones of the 1-9 lines and recoded to binary notation as before to appear on the output lines CDO. The columns are read out one by one by pulses applied in succession to strips 20 for positions 1-9 and 21 for positions A, B, O. Magnetic drum store.-Data sensed on the card is transmitted to and recorded on the drum in a number of tracks each having four subtracks signifying values 1, 2, 4, 8 to receive the binary-coded values. Each track is divided into forty storage locations, the times at which each location passes under the write head being referred to as number times NT1 to NT40. The drum makes twenty-four revolutions during each machine cycle. Each location, as shown in Fig. 4, is sub-divided into twenty portions passing under the write head in twenty digit times DT1 to DT20. Numbers are written or read on the drum only during digit times DT3 to DT18, the first and last four DT1, DT2, DT19, DT20 being used for other purposes. The significance of signals in positions DT3 to DT18, according to whether the values being handled are decimal or sterling amounts, are shown in Fig. 4 in terms of powers of ten. Writing or reading pulses 800 per revolution, are derived from a clock track D (Fig. 5). A scale of twenty counter C1 and a scale of forty counter C2 select the address in number times NT1-NT40 and the digit times DT1-DT20. Each storage location is to receive an item of data correspondingly addressed under the control of programming means and routing means are provided whereby the data container in any group of card columns can be transmitted to any location of a storage track. Plugboard, arrangements.-The data routing means comprises plugboards DTP, NTP (Fig. 6) which may have connections settable manually or by punched cards or by the use of printed connections. In the form shown they have interchangeable printed connections and have output lines DTO, NTO each consisting of 160 permanent lines of which 80 are connected as required with columnar printed connection lines CLD for positions 1-9 of the card column and the other 80 are connected with columnar printed connection lines OLD for the positions A, B, O of the card column. The twenty lines DC 11 pulsed in turn by counter C1 and forty lines DC22 pulsed in turn by counter C2 are also connected as required with printed connection lines IN, IM. The output lines DTO, NTO of like columnar significance are connected one to each input of card column control gate CCG contained in a unit CGU. A digital order indicating pulse from one of these gates is fed via a cathode follower and a diode TH1 or TH2 to an input sensing contact unit ISU (Fig. 5) and to a check sensing contact unit CSU which are alike and constructed as described above with reference to Figs. 7 and 8. The routing of the digits to the proper storage positions is effected by plugboard DTP, pulses passing through the gate unit CGU (Fig. 6) being applied on lines DTO1 to the contact strip 20 (Fig. 8) so that the 10<SP>-2</SP> pence digit is written on the drum in digit time DT7 (see Fig. 4), 10<SP>-1</SP> pence digit during DT8 and so on. These differentially timed outputs appear in succession on the 1, 2, 4, 8 output lines CDO, Fig. 7, to write gates which control the operation of write heads WH1 (Fig. 5). Energization of the write coil of a write head is adapted to make a small area of magnetization MA (Fig. 4) and the head also carries an erase coil which when energized removes any signal from the track. The drum makes twentyfour revolutions in each machine cycle, the data from the record being recorded in the first revolution, and processed in the following twenty-three. During the recording process the erase coil is energized except when a signal is fed on line CDO (Fig. 7) to the write coil. By this means all previous signals on the drum are erased. The write head WH1 (Fig. 5) is controlled by a write gate WG which passes a clock pulse CP from a drum track when enabled by the signals on the CDO lines (Fig. 7). The gates WG are enabled only during the first revolution of the twenty-four revolution cycle. This control is effected by a counter C3, Fig. 5, operated by master clock pulses. Checking.-Means are provided for checking for possible errors in the mechanical sensing, the electrical sensed data transmission and the recording on the drum. During the twenty-fourth revolution of a cycle the data on the drum is read by heads RH1 and gated to write heads WH2 on a check store track on the drum. By this time the card has passed from the input sensing unit ISU and is positioned in a check sensing unit CSU which is identical and controlled by the same gates CCG although this apparatus (Fig. 6) may be duplicated if a more certain check is required. The data written on the check drum track is compared with that sensed on the card in the second sensing station in a comparing unit COM. This comprises two gates COG1, COG2, Fig. 16, for each sub-track of the check store. The coded outputs from the check sensing station are passed to pulse shapers PS having two outputs, one giving a significant signal output N and the other a contra-significant signal output " not N." These pulse trains are applied to the gates. In gate COG1 the significant signal is gated with the contra-significant signal derived in a circuit (Fig. 14, not shown) from the read-head of the check store. In gate COG2 the contra-significant signal from the check sensing unit is gated with the significant signal from the check store of the drum. If the two signals are always opposite, no clock pulse CP is passed by the gates, thereby indicating that the two sets of data agree. If there is an error a clock pulse is passed via gate COG3 to line WRO where it operates an alarm or causes the error card to be separated.