ASCC General description

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Of major importance is the assembly of various mathematical techniques under one automatic sequence control. The fundamental operations that may be called for by the sequence control tape include: addition, subtraction, use of parentheses and brackets, multiplication, division, interpolation or the location of values of functions in mechanical tables of mathematical functions, printing or card punching of computed results, card feeding and storage of numerical data.

Addition and subtraction are accomplished with the aid of 72 adding counters, each consisting of 24 electro-mechanical counter wheels permitting computation to an accuracy of 23 significant figures. The 24th or highest order counter wheel in each adding counter is reserved for the indication of algebraic sign.

The machine will compute either positive or negative numbers. Negative numbers are expressed as complements of nine. The negative results of computations are automatically inverted and printed as true numbers with an indication of their algebraic signs.

Parentheses, brackets, or other signs of grouping and association indicating that the result of one operation or series of operations must be temporarily held over, are interpreted in the machine through adding counters employed as storage devices and through the use of summary cards which may be inserted into the problem during intermediate stages of a computation.

Multiplication is accomplished with electromechanical mechanisms in an arrangement not used by any other calculating machine. When the multiplicand is received by the multiplying unit, this unit immediately sets up the nine integer multiples of the multiplicand and stores them in counters. The process of multiplication is then completed by withdrawing such multiples of the multiplicand as may be indicated by the multiplier, and adding these together while shifting the sum of one column after each addition.

Division utilizes the same apparatus as multiplication, the only added feature being a sensing circuit designed to choose the successive integers in the quotient.

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