GB1491720A - Word processing - Google Patents

Abstract

1491720 Word processing system; magnetic recording media; digital data storage XEROX CORP 31 Oct 1974 [2 Jan 1974 (2)] 19548/77 Divided out of 1491718 Headings G4H and G4C The description of the present Specification forms part of the disclosure of parent Specification from which it is divided, but the claims are directed to the recording of data in a particular format on a magnetic record medium (e.g. card or cassette tape) by a word processing system using such a medium and operable to correct data recorded thereon. The word processing system comprises a keyboard 1, Fig. 1 (not shown), means 18 for recording information on the medium, means for reading information from the medium for transmission to a printer (2) for printout, and means (16, 17) enabling information recorded on the medium to be corrected by further information generated at the keyboard. Information is recorded on the medium in the form of at least one block data record comprising an interblock header, Fig. 3, preceding a block of a plurality of uniform length data sectors, Fig. 2, each of a maximum predetermined length, the header containing an interblock gap 600 and a portion 603 uniquely identifying the associated plurality of data sectors. Each data sector is spaced from adjacent sectors by an intersector gap 590 and contains character information 593 together with up to a predetermined number of "no-op" revision characters 594 which may be replaced by character information if the number of data characters in the section has to be expanded during correction. Blocks and sectors may correspond to pages and lines of data to be printed, the last block (page) being followed by an "end of record" (EOR) indication, Fig. 4. Each block, sector and EPR indication may be as shown (with gap 605 being the same length as gap 600 which is in turn significantly longer than gap 590), EOR being followed by a long gap 609 to help distinguish it from the block headers. Each sector also contains a portion 596 to accommodate record/replay speed variations of up to 20%, and a portion 595 including checking data to ensure correct reading and/or recording of information 593. Portion 603 of the block header includes a block-identifying character together with the block address. A similar portion 608 of EOR includes the address of the last block recorded on the medium.