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Porthole window system for computer displays

  • US 4,868,765 A
  • Filed: 01/02/1986
  • Issued: 09/19/1989
  • Est. Priority Date: 01/02/1986
  • Status: Expired due to Term
First Claim
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1. A system for generating porthole windows for a computer display, comprising:

  • a screen memory;

    an output driver connected to the screen memory and to the display for converting the contents of the screen memory into a signal suitable for use by the display;

    at least one bit save array memory for holding the contents of information windows; and

    a controller coupled to said screen memory and to said bit save array memories for selectively transferring the contents of the bit save array memories to the screen memory, and for selectively transferring information between selected bit save arrays, wherein at least one selected portion of a bit save array is not transferred to said screen memory;

    wherein said controller includes a porthole bit save array which contains an exact copy of a selected portion of one of said bit save arrays which is not transferred to said screen memory from said bit save array, wherein said porthole bit save array is updated to reflect any changes which are made in the selected portion, and wherein the contents of the porthole bit save array are transferred to said screen memory by said controller.

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