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Glossary V...


V.17 ("V-seventeen") A communications protocol defined by ITU-T for 150 bits per second.
V.21 ("V-twenty-one") A communications protocol defined by ITU-T for 300 bits per second.
V.22 ("V-twenty-two") A communications protocol defined by ITU-T for 1200 bits per second.
V.22bis ("V-twenty-two-bis") A communications protocol defined by ITU-T for 2400 bits per second.
V.27ter ("V-twentyseven-ter") A communications protocol defined by ITU-T.
V.29 ("V-twentynine") A communications protocol defined by ITU-T.
V.32 ("V-thirtytwo") A communications protocol defined by ITU-T for 4800/9600 bits per second.
V.32bis ("V-thirtytwo-biss") A communications protocol defined by ITU-T for 7200/12,000/14,400 bits per second.
V.32terbo ("V-thirtytwo-turbo") A communications protocol defined by ITU-T for 21,600 bits per second.
V.34 ("V-thirtyfour") A communications protocol defined by ITU-T for 28,800 bits per second.
V.42 ("V-fortytwo") A collective name for the error correction protocols MNP 2 to 4 and LAPM, as defined by ITU-T.
V.42bis ("V-fortytwo-biss") A collective name for the error correction protocols MNP 2 to 4, LAPM and BTLZ as defined by ITU-T.
V-Fast Class ("V-fast-class") A fore runner to the emerging V.34 protocol defined by ITU-T but not 100% compatible with it, although it would work with V.34 in most instances.
VAPOURWARE The name given to software which is as substantial as steam - that is new software where claims are made by authors, or publishers, of its imminent appearance and revolutionary features you can't possibly do without while it suffers from the serious disadvantage of not existing yet, and in many cases it may never appear.
VBI ("V-B-I") Acronym for Vertical Blanking Interval.
VCR ("V-C-R") Acronym for Video Cassette Recorder.
VDU ("V-D-U") Acronym for Visual Display Unit, which is the screen you look at, so that you can see or monitor what is going on.
VECTORSCOPE An expensive piece of equipment for analysing the colour information from a video signal. It shows both the colour and saturation levels of a video signal relative to a number of reference points on a small screen similar to an oscilloscope, and how well the signal matches these points, as well as the path taken to get there, determines the quality of the image.
VERONICA Yet another early navigation tool available on the Internet, that kept an index of Gopher items. By making a keyword search of the titles held on Veronica, you were presented with a Gopher-like menu of information which could be accessed directly from it. A Veronica search actually searched the menus of hundreds of Gophers.
VERTICAL BLANKING INTERVAL The time between each video "field" when the electron beam is darkened or "blanked" during its return to the top of a video screen. The VBI happens twice per frame and is seen as a black bar across the screen if a picture is rolling (as when the vertical hold is incorrect or when filmed using a camera that is not synchronised with it).
VERTICAL SCAN RATE The speed that the raster travels down the screen, while refreshing the image being displayed. The speed of a normal TV set is only 50 Hz whereas a monitor may be as high as 70 Hz, in other words it re-scans the tube up to 70 times per second.
VERY LARGE SCALE INTEGRATION (abbreviation"V-L-S-I") Refers to the production of chips with literally millions of components on a single chip. Because the components are close together, the electricity has a shorter distance to travel, hence the whole circuit can run faster and more reliably.
VESA (pronounced vee-sa) Acronym for Video Electronics Standards Association.
VESA LOCAL BUS A "Local Bus" type of motherboard expansion, which provides direct access from the processor and enables data to travel from expansion cards to the processor and vice versa 32 bits at a time, rather than the traditional 8 bits used by the ISA bus. However adding more than one VLB card can be a problem, which is one of the reasons Intel designed the PCI bus card.
VGA Acronym for Video Graphics Array and refers to the high-resolution colour graphics system for MS-DOS machines. Provides 80 columns by 25 or 50 line text with up to 256 colours on screen at a resolution of 1,024 x 768.
VHS (V-H-S) Acronym for Video Home Standard.
VIDEO CASSETTE RECORDER
(abbreviation"VCR")
Generally refers to one of the domestic video cassette decks using BETA, VHS, S-VHS, Video8,etc formats, where the video and sound signals were stored on to magnetic tape, with a planned maximum recording time of 3 hours, but up to 4 hours using thin tape or up to 6 or 8 hours respectively running at half speed with degraded quality.
VIDEO DISPLAY ENHANCER Electronic circuitry that can de-interlace an interlaced screen to remove the flicker and visible scan lines, and also employs scan-doubling in non interlaced modes to remove scan lines without ghosting. However, a 31 KHz monitor is required to display the resulting image.
VIDEO DISPLAY UNIT>br>(abbreviation "VDU") A generic name used in reference to dumb terminals connected to a computer, consisting of a display screen and keyboard. However the term has been extended to include all computer screens.
VIDEO CARD A card similar to a graphics card, but where the output signal is also provides at video frequencies, so that it can be displayed on a television or recorded onto video tape.
• Amiga: For Classic Amigas this may be NewTek's Video Toaster or the OpalVision card that extend the Amiga's standard video capabilities, while the AmigaOne uses standard PC cards.
• PC: Special video capture and processing cards are available for video, but most of the newer graphics cards also provide video output signals.
VIDEO TAPE RECORDER (abbreviation "VTR") Generally refers to high-end studio video tape decks.
VIRUS A 'computer virus' is a program which somebody has intentionally written that is capable under certain circumstances of reproducing and spreading itself to other computers. As a result of running the virus, it may interfere with the normal running of a computer, causing it to run slow, or for programs to crash. Many viruses actually attempt to destroy things, such as erasing files or corrupting data, and by attaching themselves to other files can be spread from one machine to another. Viruses are typically written by people who have a good knowledge of the Operating System and ways of exploiting any of the vulnerabilities within the code, probably in their need to be noticed or just because they think it is smart. Viruses cost businesses millions of dollars a year in lost productivity and virus protection processes.
VIRUS CHECKER A virus checker is a program that either runs in the background, checking certain areas of all inserted floppy disks for viruses, checking the computers memory for active viruses, checking all files including email that are read or written to a computer, or simply a program which can be run to scan all files on a disk for viruses. Some virus checkers perform all of these functions, and can also help destroy the virus program. However, new viruses can appear at any time and many virus checkers require you to download regular (weekly) updates from the vendor for which you may have to pay an annual fee, while others use generic detection methods and only require occasional updates when new types of viruses are detected.
VIRTUAL MEMORY Some computers, or special software running on other computers, can store and retrieve information on disks, as though it were part of memory, and this is completely transparent to any programs that are running and using it. On the Classic Amiga this was achieved using a program called GigaMem.
VL-BUS ("V-L-bus") Acronym for VESA Local Bus.
VLB ("V-L-B") Acronym for VESA Local Bus.
VLSI ("V-L-S-I") Acronym for Very Large Scale Integration.
VOLUME NAME The name or label assigned to a disk. For instance when you rename a disk, you change the disk's volume name.
VON NEUMANN ARCHITECTURE The term used to describe the way most convential computer chips like the 68xxx and 80xxx function, using a design originally conceived by John Von Neumann in the late 1940's. He proposed that the operating instructions (program) and the data could both be stored within the computer's memory, and how programs would run. Simply put, each instruction is analysed and the address of the next instruction is stored in a status register before the first instruction is executed. On completion of that instruction the next instruction is located by referring to the status register, and the whole operation is repeated with that instruction and so on. Some of the instructions make decisions and require the computer to branch to another instruction instead of the one whose address was stored previously. This is achieved by changing the value stored in the status register before it processes the next instruction. This may sound rather complex but it has the basis of modern computing for over 50 years and is referred to as the Von Neumann architecture after its inventor. Strangely, some newer chips such as the Transputer utilise a different technique but nobody has given it a name so it is often referred to as non-Von Neumann architecture.
VTR ("V-T-R") Acronym for Video Tape Recorder.

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Revised: September 19, 2005.