Accessing Windows device drivers from DOS programs

It is possible to access functionality of (appropriately written) native 32-bit Windows drivers from DOS programs. For this, otherwise non-existing CPU instructions - also known as BOP's, for BIOS Operation, from an early PC emulator called SoftPC - have been defined which are processed by the "invalid instruction" routine of the NTVDM (passed to by the kernel's KiTrap06 routine), kind of like a software version of the SYSCALL instruction of x86-64 CPU's. These instructions are the following:

For the development of the VDD, the Windows Driver Development Kit (DDK) or its new incarnation, the Windows Driver Kit (WDK), is required. The VDD can use the following API calls, defined in vddsvc.h, for communication with DOS programs running in the NTVDM:

More documentation:

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