A virtual page that is currently in physical memory. See also invalid page.
A named value with assigned data within a registry key. See also registry and key object.
Virtual block number
A virtual block number identifies a block (a.k.a. “sector”) relative to the start of a file. For a file with N blocks of data, the corresponding VBNs are numbered 1 through N.
Volume control block
An internal NT file system structure in which a file system maintains state about a mounted volume.
Virtual DOS machines
A protected subsystem that emulates MS-DOS and DOS-based Windows within Windows NT.
An interface to adapter-specific miniport drivers exported by the system-supplied video port driver. Video miniport drivers call these routines to obtain all system support they need to carry out I/O operations.
A whole or partial mapping of a section object in the virtual address space of a process. Note that mapping a view of a section that is backed by an executable image file, in effect, “loads” the image. Except during the system boot process, NT uses memory-mapped I/O, rather than a loader, to start program execution.
A view of memory that does not necessarily correspond to the underlying physical memory structure. For example, a given range of virtual addresses might be mapped to and backed by some number of discontiguous physical pages, even though the corresponding virtual pages can be accessed as a single, contiguous range.
Volume map control block
An opaque structure that stores VBN-to-LBN mappings for an IFS’s volume file.
A virtual file, maintained by certain NT file systems, whose contents map metadata structures of the on-disk file system. A volume file is a type of stream file.
Volume parameter block
A VPB is a structure, defined by the I/O Manager, that maps a file system’s volume device object to the device or partition upon which the volume is mounted. The file system’s device object is actually used to represent the volume (VPB) mounted on the actual device (physical device object). Device objects for physical disks, tapes, CD ROMs, and RAM disks have associated VPBs. See also mount.
Video request packet
A structure used to communicate device I/O control requests from a display driver to its corresponding adapter-specific miniport driver. For example, when a display driver calls EngDeviceIoControl, this function calls a system service and the NT I/O Manager sets up an IRP and calls the NT-supplied video port driver with that IRP. The video port driver uses the IRP to set up a VRP and calls the corresponding video miniport driver’s StartIo entry point with the VRP.