System for providing data communication between a computer terminal and a plurality of concurrent processes running on a multiple process computer

• US 4,761,642 A
• Filed: 10/04/1985
• Issued: 08/02/1988
• Est. Priority Date: 10/04/1985
• Status: Expired due to Term

• Current Assignee: American Video Graphics LP
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Huntzinger, Gregory G.
• Primary Examiner(s): Curtis, Marshall M.
• Application Number:
  US06/784,413
• Time in Patent Office: 1,033 Days
• Field of Search: 340/707, 340/721, 340/747, 340/724, 340/723, 340/750, 364/521
• US Class Current: 715/806
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

An apparatus for displaying the display outputs of a plurality of simultaneously active computer processes in corresponding windows on a single screen includes a microcomputer, a display screen and display system software. The software represents a plurality of virtual terminals, one corresponding to each active process, for emulating the operation of real terminals communicating with the processes. Each virtual terminal maintains a display list comprising a set of instructions defining a display on a screen according to the output from the corresponding process. The software also includes a screen process for maintaining a subrectangle list comprising a set of instructions for allocating window portions of the screen to the displays defined by the separate display lists. A display list processor is provided for creating the windows on the screen according to the display and subrectangle lists.

Claims

1. In a computer system having a memory and having processing means for concurrently executing multiple processes, including first processes, each of which first processes receives input data produced by a computer terminal of said computer system and produces output data for controlling display on a screen of said computer terminal, a method for permitting concurrent data communication between a plurality of said first processes and a single computer terminal, the method comprising the steps of:

initiating and concurrently executing for each of said first processes a corresponding virtual terminal process each virtual terminal process receiving input data from the single computer terminal and forwarding said input data to the corresponding first process, receiving output data produced by the corresponding first process, and maintaining a separate display list in said memory, said display list comprising data defining a display in accordance with said output data produced by the corresponding first process;

initiating and executing a screen process for maintaining a subrectangle list in said memory, said subrectangle list comprising a set of instructions defining positions and sizes of display windows to be displayed on a screen of said single computer terminal, each window corresponding with a separate display list; and

initiating and executing a display list process for periodically transmitting display data to said single computer terminal for causing said single computer terminal to concurrently display said display windows on said screen at positions and of sizes defined by said subrectangle list, each window including a display in accordance with the display defined by the corresponding subrectangle list.