GB960169A - Method of entering information into a memory device and device for performing the method - Google Patents

Abstract

960,169. Digital data storage. SVENSKA RELAFABRIKEN A.B.N. A.B. April 6, 1961 [April 14, 1960], No. 12348/61. Heading G4C. In a method of and arrangement for transferring data from a register to a cyclically operating store, such as a magnetic drum, the data is entered in the store commencing with the most significant bit and non-significant bits in positions of higher order, such as zeros, are not entered. As shown, Fig. 1, data is transferred from a register R to a magnetic drum MT, the register being scanned by a scanner A before the transfer takes place to ascertain the highest significant digit. The register R may be a contact bank in a book-keeping machine. As shown in detail in Fig. 4, the attainment of equality between the desired address of a drum sector and the drum sector addresses read from the drum MT, causes a pulse P to be applied to trigger D which changes over to enable a gate E which commences to pass clock pulses S from a timing track on the drum to step on a three stage binary counter X 1 , X 2 , X 3 the outputs of which are decoded at F to cause pulses to be applied successively to leads p 0 ..., p 7 connected to the respective stages of the register R. The stages of the register are thus scanned successively, commencing with the most significant, scanning continuing until a significant digit, as represented by the connection of a p lead to a q lead q 0 - q 11 , causes an output on a q lead to activate an "or" gate C and reset the trigger D thereby cutting off the supply of pulses to the counter X 1 -X 3 , which remains unchanged until the data in the register R is to be entered on the drum. When the entering operation begins, a five step counter T 1 , T 2 , T 3 , Fig. 1, is stepped on by the drum clock pulses, the counter outputs being decoded and fed to a distributer H whose inputs are connected to triggers I 1 -I 4 supplied with the output of a decoder B connected to the leads q 0 -q 11 of the register R so that the digits stored in the register R are successively read out in binary coded form to the triggers I 1 -I 4 , the distributer H serving to serialise the data and add a parity check bit derived from a further trigger P 1 before entry of the data on the drum MT. A circuit is also described (Fig. 2, not shown), for reading data from the drum and converting it from serial to serial-parallel form to actuate digit or machine function keys in a book-keeping machine. The register R and drum MT may be read simultaneously, the outputs being compared (Fig. 3, not shown) in a comparator which actuates an alarm if there is any inequality between the data.