Graphics display with improved window organization

Claim 1

In a data processing system of the type having a display, a buffer memory for holding a pattern to be presented on the display, a processor memory for holding programs of an operating system and user programs, and a processor for executing the programs simultaneously, a system for operating on the display screen within more than one window, an improved system for operating with multiple windows that are independent in sizes and locations comprising, means in the operating system for establishing a plurality of control blocks (DIB) wherein each control block (DIB) contains a parameter (DIBVOL) that identifies a graphic device, such as a window, to be opened with the user program whereby the number of graphic devices to be opened within each user program is dynamically defined by said user program with each user program defining at least two graphic devices, means for establishing for each said window a parameter (LUN) uniquely identifying each said window within each said user program thereby allowing each said window to be independent of other windows within said user program, means (I/0 manager) for establishing for each said window a control block (DCB) containing said identifying parameter (LUN) and containing a pointer to a driver associated with the device to be opened, means for forming for each said window a function packet specifying a predetermined area of the screen as a window for operations identified by said uniquely identifying parameter and other function packets containing one or more functions to be performed within said window and optionally containing parameters, a drvier program including means for fetching from the user program said function packets and means for executing said function packets to provide a display within the window identified by said parameter.