Patent GB-827163-A (GB)
Title: Improvements in electrical digital data storage apparatus
IPC: G11B5/004
Filed: 1955-10-25
Abstract: 827,163. Electric digital-data-storage apparatus. DIRKS, G. Jan. 25, 1957 [Oct. 25, 1955; Oct. 28, 1955; Nov. 23, 1955], Nos. 30413/55, 30860/55 and 33509/55. Class 106 (1). Digital - data - storage apparatus comprises a plurality of magnetic storage drums on parallel axes, magnetic transducing means associated with each drum, a further storage device, and means for rotating the drums in synchronism to allow transfer of data between the further store and any of the drums. General.-The invention is concerned with obtaining maximum drum storage in a given space, and various multiple-drum arrangements are discussed including a nest of open-ended coaxial cylinders, one within the other, both the inner and outer surfaces of each being magnetizable (Fig. 9, not shown). In the described embodiment there are ten main storage drums 1<SP>1</SP>, 1<SP>2</SP> . . . 1<SP>10</SP>, Fig. 1c, driven through gearing at 120 r.p.m., and the further storage comprises a drum 9 driven at fifty times this speed (i.e. at 6000 r.p.m.). Track selection.-To reach a desired track on one of the drums 1<SP>1</SP> ... 1<SP>10</SP> all the signal-head holders 11 to 15 are shifted parallel to the axes of the storage drums by a rack-and-pinion drive. The pinion 23, Fig. 3b, through which the heads are moved to a selected track, is continuously urged in a counter-clockwise direction by a slipping clutch drive. It is held in a selected position by a solenoid-controlled pawl (not shown) engaging a ratchet wheel 90 which is integral with the pinion 23. The circuit of the controlling solenoid may pass through any one of a series of stationary contacts 104<SP>1</SP> ... 104<SP>10</SP>, each of which is in series with a normally-open switch. Closure of one of these switches normally energizes the solenoid which withdraws the pawl and allows the ratchet-wheel and pinion to be rotated, moving the heads across the tracks until an insulating segment 93 reaches the contact associated with the closed switch, when the circuit of the solenoid is broken and the ratchet-wheel 90 is arrested by the released pawl. Periodically, during the counter-clockwise movement of the pinion 23, the toothless half of the pinion allows the spring- urged rack 24 and the read/record heads coupled with it, to return to their initial positions. In an alternative embodiment (Fig. 3c, not shown) the heads are coupled to the ratchet by a crank and connecting-rod and the ratchet teeth are unequally spaced to provide for equal linear displacements of the heads. In a preferred arrangement (Fig. 3d, not shown) a system of two racks and pinions, the movements of which are summed by a single pinion engaging with both racks, provides for movements corresponding to tens and units displacements for rapidly selecting any one of the hundred tracks. Entry of data.-Signals are entered into the storage from a six-channel magnetic tape, a prearranged portion (i.e. the equivalent of 100 six-bit digits) being sensed during each rotation of the drum 9 and recorded on the latter. This information is subsequently transferred to an address in the main store 11 ... 1<SP>10</SP> which is set up on a keyboard 111, Fig. 4a, or derived from punched or magnetizable tapes &c. controlling electromechanical or electronic relays. Address selection.-Depression of one of ten keys 1121... 112<SP>10</SP> closes a corresponding switch 103<SP>1</SP> ... 103<SP>10</SP> associated with one of a series of contacts 104<SP>1</SP> ... 104<SP>10</SP>, Fig. 3b, which determines the angular setting of the pinion 23 and therefore the longitudinal movement of the rack 24 which moves the signal heads to the desired track position as described above. Depression of one of the keys 1131 ... 113<SP>10</SP> leads to a similar adjustment in the tens denominations, so that the combination of both keys determines to which of one hundred track positions the read/record heads are moved. A further key in a row 114<SP>1</SP> . . . 114<SP>10</SP> selects a solenoid for energization so as to move a selected head, or group of heads, into co-operative relationship with a drum surface, as described in Specification 827,165. To select that one of the fifty sections of the selected track on which data from the drum 9 is to be recorded (or from which data is to be extracted) one key in each of rows 115<SP>1</SP> . . . 115<SP>10</SP> and 1161 ... 116<SP>5</SP> is depressed. These control contacts 1201 ... 120<SP>10</SP> and 121<SP>1</SP> ... 121<SP>5</SP>, respectively, and thereby set up the complement of the required track address in counting tubes 124 and 127. The operation of the key in row 1161 ... 116<SP>5</SP> also changes over contacts 128 and 129, thus making effective amplifiers 130 and 131. Now, when a datum signal indicating the beginning of the storage tracks is picked up from the drum 1<SP>10</SP> by a head 27, a signal passes through the amplifier 131, switching over a flipflop 136 and adding unity into the counter. The operation of the flip-flop 136 opens a gated amplifier 137 connecting all the data signal heads 73<SP>1</SP> ... 73<SP>6</SP> via rectifiers 138<SP>1</SP> ... 138<SP>6</SP> to a scale-of-one-hundred counter 140. Thus as each element of information, recorded in six parallel channels, is sensed, a pulse steps on the counter 140 which has a capacity corresponding to a unit of information on the tape (one hundred six-bit signals), and therefore a transfer pulse appears on the output channel 141 and passes to the address counter 124, 127 as each address passes the signal heads. When the counter 124, 127 returns to zero an output pulse passes on line 145 to operate a flip-flop 146 which opens a series of gates 119<SP>1</SP> . . . 119<SP>6</SP> between heads 29 ... 34 reading data from the high-speed drum 9, and the heads 73<SP>1</SP> ... 73<SP>6</SP> which now serve for recording new data in the selected address. (Switches 147<SP>1</SP> . . . 147<SP>6</SP> and 148<SP>1</SP> ... 148<SP>6</SP> are set in a positions for writing information into the store and in b positions for reading information out.) Various modifications are suggested including the provision of detachable surfaces for the main storage drums (Fig. 7, not shown). A suitable electronic counting arrangement is described.