Video computer system including multiple graphics controllers and associated method
US4862156A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1984 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | May 21, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/42
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video computer system and methods are disclosed for displaying video graphics on a video display screen. The video computer system employs two alternative video graphics controllers. A first graphics controller is typically one that has been previously available to consumers and which also has a substantial library of graphics programs which are designed to be executed compatibly thereon. The second graphics controller is typically not compatible with the first graphics controller, and accordingly executes a second type of graphics programs which also may not be compatibly executed on the first controller. A select circuit and methods are disclosed which automatically determine the type of graphics program presented to the system, and correspondingly selects the compatible graphics controller to execute the program. A protection circuit and methods are disclosed which authenticate the origin of the presented graphics programs, and which allow only authorized programs to be executed by the correspondingly selected compatible graphics controller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.