Patent GB-764524-A (GB)
Title: Improvements in or relating to electronic calculators or computers
IPC: G06F7/02
Filed: 1953-10-19
Abstract: 764,524. Digital electric calculating-apparatus. COMPAGNIE DES MACHINES BULL. Oct. 19, 1953 [Oct. 22, 1952; Dec. 8, 1952], No. 28794/53. Drawings to Specification. Class 106(1). An electronic computer co-operatable with a cyclically operated accounting machine, comprises a plugboard for setting up a normal programme of instructions which is carried out under the control of a line number memory, using order transmitters to pass on instructions such as the type of operation (TO) address (AD) and location of data within a pulse circulation store, to the utilization circuits. The computer is characterized in that it can be arranged to carry out " variant operations " which may, or may not, start or change the progress of a sequence of operations according to whether or not a predetermined condition has been fulfilled. Additional instructions may be derived from a " programme card " in an associated tabulating machine. The computer is similar to that described in Specifications 764,522 and 764,523 which are referred to. Its flexibility is improved by providing means for changing the prearranged sequence of operations under the control of comparing devices. As no storage memory is involved during the actual instruction when the decision is made, the address order transmitter AD is utilized to store the condition for changing the programme sequence as determined by a comparing operation. The conditions of response upon comparing two numbers Y and Z, are as follows:- When the instruction line number is to be changed to a prearranged number instead of the next consecutive number, the prearranged number is stored in the order transmitters OD and OF. The values of the code components in these order transmitters are not the same as when they are used normally, the binary weights of OF being divided by 4 while those of OD are multiplied by 4. Thus, the line number NL= 4 OD + “ OF. The facilities of the machine are illustrated by an example in which electricity accounts, based on a two-part tariff, are dealt with. After a comparison of the actual consumption with the maximum allowed at the first rate, the machine is programmed to proceed with the problem of computing an assumed surplus at a second rate and then adding together the total charges. A so-called " comparison-variant " instruction (VC) is, however, included in the programme at this point. It has the following effect. If the comparison has revealed that the electricity consumed falls within the basic charge (AD No. 1 above) a prearranged line number, registered in the order transmitters OD, OF, as referred to above, is now entered into the line number memory; thus, the unnecessary instructions in the programme sequence are skipped. Other types of " variant " instructions include the " tabulator variant " (VT) which transfers control of the programme to a programme card analysed by an associated tabulating machine, and the " machine point variant " (VPM) which ensures that the working programme of the computer commences at a point in the tabulating machine cycle defined in the instruction, and that, when completed, the computer stops until another defined machine point is reached. The programme cards' may bear detectable graphic signs instead of perforations. Specifications 730,297 and 764,521, [Group XL (c)], also are referred to.