Patent GB-851752-A (GB)
Title: Apparatus for effecting signal transfer between magnetic data storage tracks
IPC: G11C19/04
Filed: 1957-11-09
Abstract: 851,752. Magnetic drum data storage apparatus. DIRKS, G. Oct. 16, 1958 [Nov. 9, 1957], No. 34981/57. Class 106 (1). A magnetic drum digital data store is provided with means for transferring blocks of data from one track to a predetermined position on another track. As shown in Fig. 1, the drum 1 has tracks 3a-11a with associated heads 3-11, and a track 12a containing data (recorded for example from a punch card senser) which may be transferred to track 10a or 11a by reading with one of the heads 12/1-12/16. Each track is divided into sixteen sectors (see Fig. 2), and data characters (e.g. decimal digits) have been entered in turn into the sectors of track 12a, so that by selection of the appropriate head 12 the read out may commence with any given character at the " start of revolution " pulse from 3a and be entered into 10a or 11a commencing at sector 1. The sectors of 12a are each divided, as shown in Fig. 2, into two groups of four subsectors with the values 1, 2, 4 and 8, and each sub-sector is further divided into five storage locations so that each sector may contain five interlaced characters (as shown, sector XV contains decimal digit 5 in storagelocation 3 and decimal digit 8 in storage location 5). A counter 19 receiving " start of revolution " pulses -provides an output signal at 22/1, 22/2 ... in turn at each revolution of the drum, and this is applied via plug sockets 24 to one of the sockets 26/1-26/80 according to which character is to be transferred first, and to one of the sockets 28/1-28/15 according to how many of the following characters are also to be transferred, in that revolution. Diodes 37 set at each revolution one of the stages of a shift register 36, according to the storage location of the first character, to open one of the gates 34/1-34/5 and hence pass appropriate clock pulses from one of the tracks 5a-9a to open gate 33 or 62 for recording of data in track 10a or 11a according to the setting of switches 47, 49. Diodes 32 open one of the gates 31/1- 31/16 at the beginning of each revolution according to the sector in which the first character is stored, and through a matrix 54 set a counter 53 which is counted up one after each sector by pulses from 4a to advance the count until it registers zero, when a pulse is sent on line 57 to shift register 36 which switches to the next storage location clock pulses when the selected head 12 reaches sector 1 (since consecutive data characters in sectors XVI and I are recorded in different storage locations). The data from track 12 is recorded, commencing in sector 1 (since gate 43 is opened at the beginning of a revolution by the setting of flip-flop 44) and ending when counter 30, set according to the number of characters to be transferred in the revolution, emits a pulse to re-set 44 and close the gate 43 (and also clear register 36). The recording is effected in storage location 5, irrespective of its storage location in track 12, by the use of the gates 33 and 62 and flip-flop 41; if the character from 12a is in location 5 then gate 34/5 will be open to open gate 33 and pass the data direct, and otherwise gate 62 will be opened by the output from the selected gate 34 so that any signal in the selected location will set flip-flop 41, which on resetting by the output of head 9 will produce an output for recording in location 5. A transfer cycle similar to the above may be carried out in each of fifteen drum revolutions by connections of sockets 24 to 22/1-22/15 and to appropriate sockets 26/1-26/80 and 28/1-28/15. If recording in any selected storage location is desired, further gates similar to 34/1-34/5 may be used to control gate 33 and resetting of 41 from the potential available at terminals 22. Fig. 5 shows modifications necessary to the arrangement of Fig. 1 for transferring data from track 10a or 11a to track 12a. A plug connection 75 enables gate 46 for reading track 11a, and gate 43 is opened when the sector of 11a containing the required first character for transfer is reached, by a counter 77 set by plug connection 80 via matrix 79. The selection of the appropriate storage location in track 11a is effected by plug connection 85 to open gate 82 at the appropriate times, and the data may be re-timed for entry into the new storage location by selection of the appropriate clock pulses by counter 36 and gates 34 acting on the flip-flop 41 in a manner similar to the Fig. 1 arrangement. If the number of characters to be transferred from 11a involves the passing to sector I of track 11a, a further shifting register similar to 36 controlling gates 83 must be provided.