Method and system for device virtualization based on an interrupt request in a DOS-based environment
US5937185A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 11, 1997 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Dec 11, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2009/45579
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A technique for providing device virtualization in an MS-DOS based operating environment, using an interrupt request (e.g., a non-maskable interrupt), is described. The technique includes executing an application on a processor within the MS-DOS based operating environment and, when the application attempts to address the device to be emulated, causing a processor interrupt to occur. In response to the interrupt, the processor executes code representing the virtualization of a device. The code for servicing the interrupt and emulating the device are written in protected-mode code, stored in the extended memory area, and made available by making appropriate entries into the interrupt descriptor tables (IDTs) for the protected-mode contexts which exist for the native protected-mode operating systems and for the DOS extender. The entries made into the IDT for the protected-mode context established for the DOS extender are accomplished by intercepting communications between the DOS extender and the virtual control program interface (VCPI) and patching the DOS extender's IDT with the vectors to the stored emulation code.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.