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Glossary
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vaccine. A disinfectant or anti-virus utility that helps your computer fight computer viruses. It works by looking for the symptoms of virus activity, such as suspicious attempts to infiltrate relatively secluded areas of the hard drive. The vaccine then removes the virus, making your PC infection-free.
version. An edition of a product.
VESA. Short for Video Electronics Standards Association, a consortium of video adapter and monitor manufacturers whose goal is to standardize video protocols. VESA has developed a family of video standards that offer greater resolution and more colors than VGA. These standards are known collectively as Super VGA ( SVGA ).
VGA. Abbreviation of video graphics array, a graphics display system for PCs developed by IBM. VGA has become one of the de facto standards for PCs. In text mode, VGA systems provide a resolution of 720 by 400 pixels. In graphics mode, the resolution is either 640 by 480 (with 16 colors) or 320 by 200 (with 256 colors). The total palette of colors is 262,144. Unlike earlier graphics standards for PCs -- MDA, CGA, and EGA -- VGA uses analog signals rather than digital signals. Consequently, a monitor designed for one of the older standards will not be able to use VGA. Since its introduction in 1987, several other standards have been developed that offer greater resolution and more colors (see SVGA , 8514/A graphics standard, and XGA), but VGA remains the lowest common denominator. All PCs made today support VGA, and possibly some other more advanced standard.
video adapter. An expansion card that plugs into one of your PC's expansion slots, allowing your software and your PC's monitor to talk with each other.
video memory. A special part of RAM in which the computer stores images displayed on the screen. (See also memory and RAM.)
virtual disk. A fancy term for RAM disk, a disk created from the computer's memory. (See also RAM disk.)
virtual machine. The environment created by a Java-enabled Web browser that Java applets run within. A software simulation of another computer. A virtual machine is useful for testing software on large computers such as mainframes.
virtual memory. A use of disk drive storage that simulates RAM. Some operating systems (not DOS) borrow parts of the disk drive and swap out massive chunks of memory to a file on disk -- a swap file. That way true memory (RAM) is made available for programs that need it. The memory saved on disk can be put back into real memory when it's needed later.
viruses. A computer virus is a self-replicating program containing
code that explicitly copies itself and that can "infect" other programs
by modifying them or their environment such that a call to an infected
program implies a call to a (possibly evolved) copy of the virus. There
are two special categories of viruses that are common today, macro viruses
and worms. Computer viruses are never "naturally occurring"; they are
always man-made. Once created and released, however, their spread is not
directly under human control.
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