Method and apparatus for providing shared off-screen memory
US5245702A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1991 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Jul 5, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G5/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for allowing direct graphics access to backup storage areas in frame buffer memory used for retained windows and controlled by a graphics accelerator which includes the steps of establishing a shared memory file in system memory for the backup storage area indicating that the retained windows area initially exists in excess frame buffer memory, the shared memory file having storage to indicate the use of the shared area by a process; generating a page fault whenever access to the graphics accelerator is attempted and the state of another process is stored on the graphics accelerator; and calling a device driver in response to the page fault to switch the context stored on the graphics accelerator to that of the process attempting the access.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.