Patent GB-802188-A (GB)
Title: Electrical apparatus for use in controlling the composition of data to be read out seriatim during a read out routine from a data storage device to an output device
IPC: G06F3/09
Filed: 1956-07-16
Abstract: 802,188. Digital electric calculating-apparatus. NATIONAL CASH REGISTER CO. July 16, 1956 [July 18, 1955], No. 21901/56. Class 106 (1). [Also in Group XVI] In electrical apparatus for controlling the composition of data to be read out seriatim from a first data storage device to an output device, each item of data, e.g. decimal digit, being assigned a predetermined number of binary digit positions in the storage device, second and third storage devices store respectively binary compositions data for each item, and a marker digit shiftable to identify each successive item of data in the first device and composition data associated therewith, whereby signals are produced for actuating the output device to perform data composition operations in accordance with a desired format, the marker digit being shifted after completion of data composition operations for an item of data. As described, data from the magnetic storage drum of a digital computer is read out to an electricallyoperated typewriter. The computer is similar to that described in Specification 770,952, comprising a magnetic drum having main memory channels, and further channels arranged to form with bistable flip-flops in an arithmetic unit, one-word recirculation registers E, F, G, H (not shown). The operating sequence to carry out a computer command set up in H, is determined by a programme counter, only those operations relating to a typewriter read-out command being described in detail. Each word comprises 42 binary digits defined by binary and octal indications P 0 -P 2  and O 0 -O 13 . Fig. 10 shows an example of a read-out command which comprises command-identifying digits in O 12 , O 13  and numbers m1, m2, m3 in positions O 11 -O 8 , O 7 -O 4  and O 3 -O 0 ; m1 m2 are the main memory addresses of the first word to be read out and of an editing code word which are passed to registers E, F, respectively (see Figs. 11 and 13), and m3 defines the number of words to be read out. A word to be read out comprises a 9-digit decimal number in positions O 0 -O 11 , each decimal digit being represented by four binary digits as shown, and overflow and sign indications (" 1 " for overflow or " minus ") in positions P 0 O 12  and P 1 O 12 . These indications and decimal digits are read under control of a marker pulse in register G which is inserted in position P 0 O 12  and successively shifted four binary places to the right. For each decimal digit, a " 1 " in the corresponding position α, #, γ ot #, Fig. 4, of the editing code word indicates respectively that the typewriter is to (1) space instead of printing succeeding zeros; (2) print a decimal point; (3) tabulate; or (4) stop further printing of the word being read out. Operations (1)-(3) are effected by setting corresponding flip-flops A10-A12 respectively (not shown), such flip-flops, as well as the data in register E, causing different combinations of further flip-flops (A1-A6, not shown), forming a character code register, to be set to select the appropriate typewriter keys. For each operative combinations of flip-flop outputs a key-operating relay such as 203, Fig. 9, is energized through amplifier 201; and for each character-printing operation, shaft 207 makes a revolution during which cam 208 operates switch 209 whereby signal T1 applied to the computer is lowered in potential, further programme counter sequencing being delayed until the signal regains its normal high level. The example illustrated in Figs. 10-13 relates to transactions in a retail store. The first word, Fig. 11, read from address 1200, is positive with no overflow which causes the typewriter to space, the marker pulse being shifted toO 10  P 2  for reading out the highest decimal digit. Flip-flop A10 is initially set so that, since this digit is a " 0," the typewriter again spaces and the marker pulse shifts to O 9  P 1 . The editing code, Fig. 13, now indicates that a decimal point is required; A10 is then set " false," and the point is printed followed by its corresponding digit (0) and the two succeeding digits as indicated in Fig. 15. The " 1 " in α position O 7  P 2  of the editing code sets A10 " true," and when the marker pulse shifts to the next digit, position O 5  P 1 , the " is " in the # and γ positions cause a tabulate operation and then the printing of another decimal point. This is followed by printing of the next two digits (76), and then a further tabulate operation, and so on, Fig. 15. After the whole of the word has been dealt with, " 1 " is added to address m1 and " 1 " os subtracted from number m3. The second word, Fig. 12, at address 1201 is then passed to register E and is edited and printed as indicated in Fig. 15, under control of the same code word, Fig. 13, in register F. Since the second word is negative with no overflow, a " - " sign is printed (for words in which an overflow is indicated, the character " P " or " N " is printed instead). Since the number m3 has now been reduced to zero, indicating that that all the required words have been read out, the computer proceeds to the next programme command. Specification 770,952 is referred to.