GB801684A - Column shift device for an electronic digital computer - Google Patents

Abstract

801,684. Digital electric calculating apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 14, 1954 [Dec. 17, 1953], No. 36137/54. Class 106 (1). An electronic digital computer having column shift apparatus comprises first and second magnetic storage tracks (1, 2, Fig. 1, on a magnetic drum), each having associated input and output means, a first link adapted to convey data from the output of the first storage track to the input of the second storage track (via a tapped delay line and a switching unit), a second link adapted to feed back data from the output of the first storage track to the input thereof (via the whole length of the tapped delay line) a third link adapted to feed back data from the output of the second storage track to the input thereof (via an adder), and time delay means (the tapped delay line and switching unit) including a plurality of time delay elements for introducing a variable number of time delay increments into one of said links (the said first link). The machine described employs a sevenbit bi-quinary decimal code, each number being stored on seven parallel channels on a drum, the seven channels being referred to collectively as a track, and uses the adder described in Specification 800,273. The tapped delay line consists of twenty-eight unit delays of the kind described in Specification 756,285, four for each channel, and can introduce a delay of up to four digits. The switching unit comprises gates of the kind described in Specification 741,595. As described the " zero " position of track 1 is two digits ahead of that of track 2 so that relative to track 2 the contents of track 1 can be shifted up to two digits either backwards or forwards. In a second embodiment (Fig. 2, not shown), described in general terms only, the variable delay occurs not in the said first link but in the said second link. Specification 710,554, [Group XL (c)], also is referred to.