“VAC” to “VV”

VAC

(n.) volts alternating current.

validate

(v.) To have an application verify that the contents of a text field are appropriate to the function.

value-added reseller

(VAR) (n.) A company that buys hardware and software, adds more features or services, then resells the upgraded products.

VAR

See value-added reseller.

variable

(1) (n.) A symbol with a value that might change. In the shell, the variable is a symbol that represents some string of characters. You can use a variable in an interactive shell as well as within a shell procedure. Within a shell procedure, examples include positional parameters and keyword parameters.

(2) (n.) An item of data that is named by an identifier. Each variable has a type, such as int or Object, and a scope. See also class variable, instance variable, local variable.

VDC

(1) (n.) virtual device coordinates.

(2) (n.) volts direct current.

VDC transform

(n.) In computer graphics, the final transform in the transformation pipeline that provides the mapping between virtual device coordinates (VDC) and device coordinates.

VDC transformation matrix

(n.) In computer graphics, the transformation matrix that maps the clip-space window onto a rectangular region of the raster, which is called the raster viewport.

vector

(1) (n.) A line segment on a display surface with beginning points and endpoints that are identified by x, y coordinates on a grid.

(2) (n.) A conceptual direction (perhaps with length) that denotes, for example, a light-ray direction or an object's boundary.

vertex

(n.) The location at which vectors and polygon faces or edges intersect. In transformation algorithms, an object's vertexes describe the object's location and its location in relation to other objects.

vertical blanking

(n.) The number of scan lines in a field that are mandated to contain nothing except field sync and blanking. Only a small number of vertical interval lines are blanked.

vertical drive

(n.) A pulse that contains vertical synchronization information that lasts the duration of vertical blanking.

vertical interval

(n.) The raster lines that are precluded by a video signal standard from containing a picture. You can convey those vertical interval lines that are not required to be blanked as test signals (VITS), a reference signal (VIRS), timecode (VITC), closed captioning data (CC), teletext, or other information.

vertical refresh rate

(n.) A monitor specification that describes the rate at which one horizontal refresh cycle is completed. The higher the vertical refresh rate, the less flickering on the screen.

very-large-scale integration

(VLSI) (n.) The process of placing more than 100,000 transistors on one chip.

VESA local bus

(Video Electronics Standards Association local bus) (n.) The first standardized local bus. Common on IA systems, the VESA local bus is an extension of the ISA bus, which is directly connected to the central processing unit (CPU) data bus. Also called VL bus (VLB).

VEU

(n.) volume end user.

VF

(n.) voice frequency.

VGA

(n.) video graphics array.

VHF

(n.) very high frequency.

video interface

(n.) A high-speed interface that is used with the SPARCprinter^TM and the SPARCprinter SBus printer card.

video random access memory

(VRAM) (n.) A type of dynamic RAM (DRAM) that is used in high-speed graphics frame buffers. With conventional DRAM, both the processor and the frame buffer logic must access RAM by sharing the same signal lines or buses on the RAM chips. VRAM provides separate buses for the processor and the frame buffer logic.

video (random access memory) single inline memory module

(VSIMM) (n.) A small printed circuit card that contains dynamic random access memory (DRAM) chips for storing video images.

viewing pipeline

(n.) The process by which picture data are translated from user input to the screen display. In the 3-D viewing pipeline, for example, an object is defined by the application developer in model coordinates. The model coordinates are mapped to world coordinates. The world coordinates are mapped to normalized device coordinates (NDCs). The NDCs are mapped into device coordinates. The final picture is then displayed.

view model

(n.) In computer graphics, a model that specifies the geometric aspects of image formation, determining the orientation of images and the spatial relationships between objects.

viewport

(n.) A specified window on a display surface that usually shows only part of a document or graphic.

view transform

(n.) In computer graphics, the transform that maps graphic objects that are defined in world coordinates to normalized device coordinates (NDCs) where viewing operations occur.

view transformation matrix

(n.) In computer graphics, the transformation matrix that maps graphic objects from world coordinates (WCs) to normalized device coordinates (NDCs). The view transformation matrix can be specified directly or derived from the matrix product of the view orientation matrix and the view mapping matrix.

view volume

(n.) In 3-D, the conceptual 3-D space between the user's eye point and infinity. The depth of the view volume becomes finite if front and back clipping planes limit the drawing space that is available to the application. The width of the view volume, though theoretically infinite, is limited by the display surface's edges.

virtual address

(1) (n.) A 16-bit integer that identifies a byte “location” in virtual address space. The memory management unit translates the virtual address into a physical address.

(2) (n.) The address that identifies a virtual block on a mass-storage device.

virtual circuit

(n.) An apparent connection between processes that is facilitated by the Transmission Control Protocol (TCP). A virtual circuit enables applications to “talk” to each other as if they had a physical circuit.

virtual device coordinates

(n.) In computer graphics, a device-independent coordinate system that isolates the specification of view boundaries from device coordinates.

virtual machine

(n.) An abstract specification for a computing device that can be implemented in different ways, in software or hardware. You compile to the instruction set of a virtual machine, much as you would compile to the instruction set of a microprocessor. The Java^TM virtual machine consists of a bytecode instruction set, a set of registers, a stack, a garbage-collected heap, and an area for storing methods.

virtual memory

(n.) A condition in which a user program can be larger than physical memory. Virtual memory is possible through a storage hierarchy in which a program's virtual image is stored in secondary storage while main memory stores only active program segments.

VIS

(n.) Visual Instruction Set.

visual

(n.) In the X protocol, the specifications for color handling for a drawable image, including visual class, depth, and type. The visual accounts for the differences between various types of hardware in determining the way pixel values are translated into visible colors within a window. A particular screen can support only one visual type.

visual editor

(n.) An editor that shows a screenful of text at a time and enables you to move the pointer to any part of the screen and make changes. An example is the UNIX® system vi program. See also screen editor. Contrast with line editor.

visualization

(n.) A method for creating graphical models to represent complex (typically scientific) data. See also volume rendering.

VLAN

(n.) virtual local area network.

VLB, VL bus

See VESA local bus.

VLF

(n.) very low frequency.

VLSI

See very-large-scale integration.

VLSM

(n.) Variable-Length Subnet Mask.

VM

(n.) Volume Manager.

VMEbus

(n.) An interfacing system that connects data processing, data storage, and peripheral control devices in a closely coupled configuration.

volatile memory

(n.) Compare with nonvolatile memory.

volume rendering

(n.) A method of computing solid volume data for graphical display in volumetric models that are composed of 3-D elements which are called voxels. Direct volume-rendering techniques enable you to manipulate the volume data as a solid structure that you can slice to expose internal views.

VOLSER

(n.) volume serial number.

voxel

(volume element) (n.) A 3-D element that describes the data in a volumetric structure. See also volume rendering.

VP

(n.) virtual partition.

VPN

(n.) virtual private network.

VRAM

See video random access memory.

VSIMM

See video (random access memory) single inline memory module.

VTOC

(n.) volume table of contents.

VV

(n.) virtual volume.