Improvements in or relating to electronic digital computing devices

Abstract

Abstract 734,073. Digital electric calculating-apparatus. NATIONAL RESEARCH DEVELOPMENT CORPORATION. June 5, 1950 [June 22, 1949], No. 16588/49. Divided out of 731,341, Class 106 (1). In an electronic digital computer in which operations are controlled by successively selected instruction words stored in the computer, means for altering an instruction word under the control of an applied modifying word are provided in the path by which each instruction word is read out from its normal storage location and fed to a control system, whereby the instruction word effective in the control system may be altered from that which is supplied from the store. The computer described is related to the modification described in Specification 734,074 of the complete machine described in Specification 731,341 employing C.R.T. stores as described in Specifications 645,691, 657,591 and 705,474. As shown, instruction-modifying words are stored in a special store BS of which the C.R.T. screen, as described, has two 40-digit lines B 1 , B o each holding two words (the words on B o being normally zero). The first or " C " digit of each control instruction stored in control unit CL determines which half of a line in the main store shall be read out to form the present instruction as described in Specification 734,074, and similarly selects one half of the line B o or B 1 , the line itself being selected by the first or " b " digit of the present instruction through Y-shift generator 85 (Fig. 14, not shown). The selected instruction-modifying word is passed through gate 84 to the adder 30 (or a subtractor) of the control unit at the same time as the present instruction is passed thereto from gate OTG. Words may be entered into the store BS through gates OTG and 83 and a one-digit-shift or delay circuit 86. Reference is made to other forms of store, e.g. electromagnetic arrangements or supersonic delay lines. Specifications 682,156, 692,853, 693,424, 705,477, [Group XL (c)], 705,479, 734,071 and 734,075 also are referred to.

Inventors

• 👤 Frederic Calland Williams
• 👤 Maxwell Herman Alexande Newman
• 👤 Tom Kilburn
• 👤 Geoffrey Colin Tootill

Bibliographic Details