Browse Prior Art Database

Disk File/Display Synchronization System

IP.com Disclosure Number: IPCOM000081549D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 42K

Publishing Venue

IBM

Related People

Norman, RJ: AUTHOR

Abstract

A disk file 10 is used in cooperation with a cathode-ray tube (CRT) display unit 11 under interactive manual control, by an operator through a manual keyboard 12. Keyboard 12 inputs data for positioning the read head of file 10 at appropriate locations, for securing desired data to be transferred to a message buffer 13 holding the data being displayed. An Up-Down Counter UDC 14 receives control count values for indicating how far to go, e.g., how many increments of record address locations, sections of a program or program marks should be passed by a second up down counter known as, the File Address Register (FAR)15, before the appropriate next address is reached. The clock is used to increment the counters 14 and 15.

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Disk File/Display Synchronization System

A disk file 10 is used in cooperation with a cathode-ray tube (CRT) display unit 11 under interactive manual control, by an operator through a manual keyboard 12. Keyboard 12 inputs data for positioning the read head of file 10 at appropriate locations, for securing desired data to be transferred to a message buffer 13 holding the data being displayed. An Up-Down Counter UDC 14 receives control count values for indicating how far to go, e.g., how many increments of record address locations, sections of a program or program marks should be passed by a second up down counter known as, the File Address Register (FAR)15, before the appropriate next address is reached. The clock is used to increment the counters 14 and 15. For example, if FAR 15 is to be indexed "20" records, then the UDC 14 is set at "20", and the clock indexes FAR 15 by "20" while it counts the UDC 14 to zero.

File 10 contains records which are addressed by tracks, sectors of tracks, and records on three ranked levels. The modulo-3 Record Address Register (RAR) counter (3 records per sector) initially at zero, overflows or carries 6 times (3x6=18) and ends up with a decimal remainder value of 2. The modulo-15 counter Sector Address Register (SAR) (15 sectors per track) overflows or carries once to increment the Track Address Register (TAR) to 1, so the FAR address is 1-6-2 for track 1, sector 6, record 2. Thus sector 6 on track 1 is transferred on bus 17 in its entirety to Intermediate Buffer (IB) 16, and the RAR points via address bus 18 to the address in the IB 16 which is under consideration. Then the UDC 14 is used as an address register by the keyboard operator, to insert the record pointed to into a selected location in the message buffer 13 being displayed.

File 10 is arranged to have 3 records (1 record = 1 row of display) per sector, 15 sectors per track, and 75 tracks per file. In reading through many records, it is necessary to load successive sectors into IB 16 and to change tracks at the end of the la...