Patent GB-1530444-A (GB)
Title: Automatic writing system and methods of word processing therefor
IPC: B41J5/30
Filed: 1974-11-11
Abstract: 1530444 Automatic writing system XEROX CORP 7 Nov 1975 [11 Nov 1974] 48626/74 Heading G4H In an automatic writing system including a microprocessor 16, a keyboard 1, a printer 2 and means 18 for recording information entered at the keyboard and for selectively playing back recorded information, means are provided whereby lines of recorded information may be played back and printed with adjacent lines being printed in opposite directions.- This alternate-direction printout occurs in a highspeed playback mode; to increase the speed still further, escapement associated with a space may be deferred and executed with the escapement for the succeeding character, and the direction of printing for a given line may not be reversed if this would result in unnecessary print carriage movement. Each character to be printed ascesses a store 43 to produce a 12-bit word containing the ASC11 code (7 bits), the character width (3-bits) and the required hammer force (2 bits). A similar 12-bit word is used for paper indexing and carriage displacement (1 bit for direction, 11 bits for distance). The information for alternate lines of print is fed into respective buffers 35, 36 connected to a print stack which forwards data to the printer as fast as it can be printed thereby. Data is read into and then from buffer 36 to the stack for printing in one direction; data for the next line is loaded into this buffer as soon as it has been cleared and while the printer is receiving the contents of the stack. This next line data is transferred to buffer 35 and, if it is to be printed in a reverse direction, it is transferred to the stack when this is empty; however, if the direction cannot be reversed, buffer 35 is cleared and the data is transferred from buffer 36 as before. The printer is a "daisy wheel" printer with a carbon or cloth ribbon (which may be multicoloured) and with interchangeable type facilities, e.g. for foreign languages. The ribbon may be displaced with the printing of each character and may be moved out of the way of the characters last printed. Typamatic, editing, justifying and document positioning facilities are available, and a CRT display may be provided for final formatting prior to printing. Various audible and visual indicators are provided to apprise the operator of system operating conditions. Processing may be implemented in 10- or 12-pitch or proportionally spaced modes with a choice of line spacings. The automatic writing system is a modification of that disclosed in Specification 1,491,718 and includes common data, instruction and status busses 19-21. Microprocessor 16 (Figs. 3-5, not shown) controls the manipulation and transfer of data among the following peripherals, all of which are of equal status: keyboard 1, printer 2, record media station 18, buffers and miscellaneous storage 17, printer data store 14 and program time delay 16A. The microprocessor comprises a ROM 80 having 8K of storage divided into eight 1K "major pages" each containing four 256 16-bit words B 0 -B 15  (Fig. 5), hexadecimal code being used. In addition, all data is transferred via a holding register M and an ALU 84 which detects, inter alia, whether each word represents information or a command. The microprocessor controls the operation of each peripheral as a function of the program in progress, the status conditions of the peripherals and the data being transferred. Record media transport station 18 (Figs. 13-15, not shown) is as disclosed in the abovementioned application, except that the media may be magnetic tapes or cards, or even paper punched tape (cassettes 7, 8 are shown in Fig. 1). A whole line of data is accumulated in buffer 35 or 36 and read from or recorded on a record medium character by character (in NRZ, biphase, &c.). Buffers & storage 17 (Fig. 11, not shown) comprises a 1024 8-bit RAM 34, two quarters of which are allocated to buffers 35 and 36, the remainder forming a general store 37. Program time delay 16A (Fig. 12, not shown) provides all the real time delay intervals required by the system, and includes ¢ sec. and 2 m.sec. delay counters (661, 662). Apart from the description of the peripherals of the system, there are also provided flow charts, described in detail with reference to Figs. 16-28 (not shown), for the following operations:- initial idle routine (microprocessor monitors conditions on the common status bus); escapement and character printing; play/skip/duplicate modes; edit control and stop conditions; underscore; margin control; justification; automatic printing from a record medium; centring; right flush and column centring; auto log printout from record medium; text string search in record medium. The system may also form part of a larger system connected into a telecommunications network by means of modems.