Method and system for device virtualization based on an interrupt request in a dos-based environment
Patent 5790837 Issued on August 4, 1998. Estimated Expiration Date: 
September 11, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
September 11, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesPersonal computer with interface controller Reentrant protected mode kernel using virtual 8086 mode interrupt service routines Method and apparatus for performing a takeover of a microprocessor Method for providing protected mode services for device drivers and other resident software Patent #: 5459869 InventorsAssigneeApplicationNo. 712363 filed on 09/11/1996US Classes:703/25, I/O adapter (e.g., port, controller)710/48, Input/Output interrupting710/50, Vectored711/2, Addressing extended or expanded memory711/203, Virtual addressing712/4, Distributing of vector data to vector registers713/100RECONFIGURATION (E.G., CHANGING SYSTEM SETTING)ExaminersPrimary: Teska, Kevin J.Assistant: Phan, Tho Attorney, Agent or FirmInternational ClassesG06F 012/08G06F 009/30 AbstractA 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).Other References
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