Patent GB-1274768-A (GB)
Title: Data processing system
IPC: G09G5/00
Filed: 1969-10-02
Abstract: 1,274,768. Cathode-ray tube displays. INTERNATIONAL BUSINESS MACHINES CORP. 2 Oct., 1969 [7 Oct., 1968], No. 48402/69. Heading H4T. [Also in Division G4] A data processing system can display the contents of more than one of a plurality of storage registers simultaneously on a display medium, and can display a visual indication, movable over the medium under manual control, to selectively indicate the displayed contents of any particular register, an arithmetic unit being capable of performing a manually-initiated arithmetic operation on the contents indicated by the visual indication. A keyboard-controlled calculator includes an electronic "worksheet" store (for the contents of an accountant's worksheet, i.e. alphabetic row and column headings and numerical data), a scratchpad store (with four sections), a memory register associated with the worksheet store, an entry register and a result register. A toggle switch on the keyboard selects either (a) the worksheet store, or (b) the scratchpad store and result and entry registers, for display on a CRT, except that in the first case only part of the worksheet store is displayed viz. a rectangular area of the numerical data and the relevant row and column headings. In this case, a cursor is also displayed and can be moved under keyboard control. The part of the worksheet store displayed is altered by moving the cursor outside a rectangle defined by displayed markers, in the appropriate direction. Four keys move the cursor up, down, left, right respectively, by one step (light depression) or continuously (further depression). Two keys (reverse tab and tab) move the cursor to the left or right respectively to the next tab stop. Tab stops are preset during entry of the column headings by moving the cursor to the required position and pressing a tab set key. A return or an elevate key moves the cursor until it is on the left or upper boundary of the worksheet numerical data, respectively. The keyboard also controls the system to enter alphanumeric data from the keyboard into the field or position of the worksheet store corresponding to the cursor position via the entry register, or into the first of the scratchpad store sections via the entry register the data already in a section being shifted into the nexthigher numbered section, or to load the first scratchpad store section from the result register, or to load the entry or result register from the cursor-indicated field of the worksheet storage, or perform addition, subtraction, multiplication or division with the contents of the entry and result registers (the result register receiving the result except in the case of division when the quotient goes to the first section of the scratchpad store and the result register receives the remainder), or to transfer the contents of the result register to the cursor-indicated field of the worksheet storage for display (or to do this only if the result is positive or only if negative), or to store the cursor-indicated field of the worksheet store in any selected section of the scratchpad store, or to underscore worksheet data once or twice, or clear the cursor-indicated field or the result register, or replace a cursor-indicated digit by a new digit from the keyboard, or select the sign being assigned to numbers being entered, or copy one field of the worksheet store into another field (both indicated by the cursor in turn). An end heading key is depressed during data entry to the worksheet store to indicate the lower boundary of the column headings, the right boundary of the row headings being indicated by the first tab stop. Besides the worksheet information, the worksheet store has a row storing tab stops. Under control of respective keys, the worksheet store can be loaded from or read out to an input/output unit, e.g. a magnetic card read/recorder, a magnetic card reader plus a printed or an electronic data processing system. A programme store is provided capable of holding eight programmes of up to 64 operations each. A programme advance key is repetitively pressed to select one of them, three lamps indicating which is currently selected. All operations entered on the keyboard between pressing of a learn programme key and a programme end key are encoded and loaded into the selected eighth of the programme store. Pressing a repeat programme key causes the operations of the currently selected programme to be read out (non-destructively) and decoded to control the system. Conventional decimal point facilities are provided. Details of display control.-The CRT display is by selectively blanking a raster. The horizontal and vertical positions of the cursor are specified by respective counters. Three further horizontal counters specify respectively the positions (in the worksheet electronic store) of the right boundary of the row heading information (i.e. the left boundary of the numerical data), and the left and right boundaries of the rectangle of numerical data actually displayed. Three further vertical counters similarly specify respectively the positions of the lower edge of the column heading information (i.e. the upper boundary of the numerical data), and the upper and lower boundaries of the rectangle of numerical data actually displayed. The horizontal cursor position counter is incremented, reset to zero, or loaded with the contents of the first further horizontal counter or the output of a tab stop store (see below), under keyboard control to produce the appropriate movements (see above). During a set tab operation, the contents of the position counter are copied into the tab stop store which is addressed by a counter, and the position counter contents in the first such set tab operation are copied into the first and second further horizontal counters. The vertical cursor position counter is incremented, decremented, reset to zero, or loaded with the contents of the first further vertical counter under keyboard control similarly. Depression of the end heading key copies the counter contents into the first and second further vertical counters. The second and third further horizontal counters are decremented and incremented respectively to keep the horizontal cursor position count greater than the former and less than the latter, and a return operation reloads these second and third counters from the first further horizontal counter and with the width of the displayed rectangle of numerical data respectively. Similar provisions are made for the second and third further vertical counters (in connection with the vertical cursor position count and the elevate operation). A horizontal display storage address register addresses the worksheet store to partially select the character to be displayed at any instant, and is incremented (by clock pulses) until it equals the first further horizontal counter when it is loaded from the second further horizontal counter, after which it is incremented until it equals the third further horizontal counter when it is reset and the operations repeat. A similar provision is made for the vertical addressing of the worksheet store for character selection, except that the vertical display storage address register is incremented with each reset of the horizontal display storage address register instead. Modifications.-The worksheet and scratchpad stores could be displayed simultaneously on separate CRTs. Gas panel displays could be used instead of CRTs. A circular display pattern could be used with the cursor position defined by polar co-ordinates rather than rectangular cartesians as above.