(19)
(11) EP 0 147 542 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.07.1989 Bulletin 1989/30

(43) Date of publication A2:
10.07.1985 Bulletin 1985/28

(21) Application number: 84111872.2

(22) Date of filing: 04.10.1984
(51) International Patent Classification (IPC)4: G09G 1/00, G09G 1/16
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 17.10.1983 US 542572
17.10.1983 US 542376

(71) Applicant: International Business Machines Corporation
Armonk, N.Y. 10504 (US)

(72) Inventors:
  • Cheselka, Harry
    Saugerties New York 12477 (US)
  • Lucash, Jeffrey Stuart
    Kingston, NY 12401 (US)
  • Vincent, William Doosevelt
    Poughkeepsie New York 12601 (US)
  • Mann, Joy Lynn
    Port Dwen New York 12466 (US)

(74) Representative: Bailey, Geoffrey Alan 
IBM United Kingdom Limited Intellectual Property Department Hursley Park
Winchester Hampshire SO21 2JN
Winchester Hampshire SO21 2JN (GB)


(56) References cited: : 
   
       


    (54) A multiple window display system


    (57) A multiple window display system is provided for displaying data from different applications in a multi-tasking environment. The display system includes plural screen buffers (12, to 12n) for storing character codes and attribute codes of data which may be displayed on the display screen. Task selection means (26) selectively couples the output of a single selected one of the plural screen buffers to the character generator (16) and attribute logic (18) at any given time. Address modification means (20, to 20n, 22, to 22n) permits changes to be made in the display windows. The software driver includes screen control blocks (32), window control blocks (34), presentation space control blocks (36), presentation spaces (38), and a screen matrix (40) in system memory. The presentation spaces (38) receive application data for plural windows of the displayable area. Each window defines the whole or a subset of a corresponding presentation space. The screen matrix (40) is mapped to the display screen and filters data from the windows of the presentation spaces to the screen buffer to designate which of the data will be shown in corresponding positions on the display screen.






    Search report