Standard VxD Devices

Description the VxDs that make up Windows 95 and the services that VxDs can use. The overview includes information on the following devices:

• DMA Device (VDMAD)

  Device driver that virtualizes direct memory access (DMA). (The source code for VDMAD.VXD is located in the Base\Samples\Vdmad directory.)

• MS-DOS Manager (DOSMGR)

  Device driver that virtualizes MS-DOS.

• Page Swapping (PAGEFILE and PAGESWAP)

  Devices drivers that handle virtual memory. (The source code for the pagefile device, DYNAPAGE.VXD, is located in the Base\Samples\Dynapage directory.)

• Programmable Interrupt Controller (VPICD)

  Device driver that virtualizes the programmable interrupt controller (PIC).

• V86-Mode Memory Manager (V86MMGR)

  Device driver that manages memory for V86-mode applications, supporting Extended (XMS) and Expanded (EMS) memory.

• Virtual Device Loader (VXDLDR)

  Device driver that loads and unloads VxDs dynamically.

• Virtual File Cache (VCACHE)

  Device driver that provides file caching services.

• Virtual Math Coprocessor (VMCPD)

  Device driver that virtualizes the math coprocessor.

• Virtual Power Device (VPOWERD)

  Device that provides power management services.

• Virtual Shell Device (SHELL)

  Device driver that provides shell services (message display, contention resolution, message posting, monitoring of virtual machine properties, and communication with applications and dynamic-link libraries).

• Virtual Timer API (VTDAPI)

  Device driver that provides timer services.

• Virtual Timer Device (VTD)

  Device driver that virtualizes the hardware timer device.

• VWIN32 Services (VWIN32)

  Device driver that provides Win32 VxD services.