Open systems software backplane architecture for federated execution of

Abstract

A plurality of computer application programs have respective display generation routines for generating respective program video displays onto a computer display screen. Backplane software operates all of the respective display generation routines to generate a overlayed, composite video display of the respective program video displays. The software system fuses the display outputs of each of a plurality of independent application programs into a single overlayed screen display. More particularly, the software backplane architecture interrupts the draw subroutine calling sequences of each independent application program, and redirects those sequences to the backplane software. The backplane software initiates a redraw command to the application program to in turn operate the display generation routines to cause a display. Since all of the independent application programs have draw sequences under control of the backplane software, the application programs remain independent of each other. A coordinates table provides offset coordinate and orientation data for each application program so that the program displays are offset by the correct amount and are oriented to like attitudes. The backplane software multiplexes the input devices to each subscribing independent application program integrated into the architecture. Each application program executes in the originally designed code and language and executes on input commands as if it were a stand-alone, un-integrated application program.