DPMI Implementation in OS/2 Version 2.0

OS/2 Version 2.0 provides DPMI services to applications running in VDMs. The DPMI Version 0.9 specification is fully supported, and the architecture of the DPMI implementation is such that both the API functions and the underlying services are independently expandable to cope with future versions of DPMI.

DPMI support under OS/2 Version 2.0 is divided into three components:

  • The DPMI API is implemented using the DPMI API Layer, a virtual device driver which services INT 31h requests from applications.

  • The operating system kernel provides support for the DPMI VDD and the Virtual Programmable Interrupt Controller (VPIC).

  • Protected mode hardware interrupts are routed via the VPIC.

    DPMI is service request driven. An application first makes an INT 31H service request, which is handled by the DPMI VDD, calling the kernel for basic services such as allocating memory.

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