What is VCI?
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Stands for "Virtual Channel Identifier." The VCI, used in conjunction with the VPI (virtual path indicator), indicates where an ATM cell is to travel over a network. ATM, or asynchronous transfer mode, is a method that many ISPs (Internet Service Providers) use to transfer data to client computers. Because ATM sends packets over fixed channels, the data is easier to track than information sent over the standard TCP/IP protocol.
The VCI within each ATM cell defines the fixed channel on which the packet of information should be sent. It is a 16-bit field, compared to the VPI, which is only 8 bits. Since this numerical tag specifies the virtual channel that each packet belongs to, it prevents interference with other data being sent across the network.
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What is Vector?
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Mathematically, a vector is a quantity, defined by both magnitude and direction. For example, one vector could be illustrated by an 1 inch arrow pointing at a 30 degree angle. Another vector may be 2.5 inches and point at 160 degree angle. In the computer world, vectors are used to define paths in certain types of images, such as EPS files and Adobe Illustrator documents. These images are often called vector graphics since they are comprised of vectors, or paths, instead of dots. Vector graphics can be scaled larger or smaller without losing quality.
In computer science, a vector can also be used to refer to one dimensional array. For example, a vector called "fibonacci" that stores the first six values of the Fibonacci sequence would be defined as follows:
fibonacci[0] = 0, fibonacci[1] = 1, fibonacci[2] = 1, fibonacci[3] = 2, fibonacci[4] = 3, fibonacci[5] = 5
Still, most people refer to a one-dimensional array simply as an "array." But using the term "vector" does sound a bit more cool.
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What is Vector Graphic?
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Unlike JPEGs, GIFs, and BMP images, vector graphics are not made up of a grid of pixels. Instead, vector graphics are comprised of paths, which are defined by a start and end point, along with other points, curves, and angles along the way. A path can be a line, a square, a triangle, or a curvy shape. These paths can be used to create simple drawings or complex diagrams. Paths are even used to define the characters of specific typefaces.
Because vector-based images are not made up of a specific number of dots, they can be scaled to a larger size and not lose any image quality. If you blow up a raster graphic, it will look blocky, or "pixelated." When you blow up a vector graphic, the edges of each object within the graphic stay smooth and clean. This makes vector graphics ideal for logos, which can be small enough to appear on a business card, but can also be scaled to fill a billboard. Common types of vector graphics include Adobe Illustrator, Macromedia Freehand, and EPS files. Many Flash animations also use vector graphics, since they scale better and typically take up less space than bitmap images.
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What is Veronica?
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The name actually stands for "Very Easy Rodent-Oriented Netwide Index to Computerized Archives." Pretty weird, I know. The "rodent" part of the acronym refers to how the Veronica utility allows you to search all of the world's gopher servers using keywords. (That's about 10 million items from over 6,000 gopher servers.) After searching for the terms, Veronica displays a list of gopher menus and articles containing the key words you searched for. The more recent versions of Veronica can also search certain Web pages, newsgroups, and FTP sites.
Unlike most search engines, Veronica searches for keywords only in gopher server menu titles, and doesn't look throught the entire text of documents. When searching with Veronica, you can use the logical operators AND, NOT, and OR to help narrow your search. Also, typing an asterisk (*) at the end of a word will match anything starting with that word. Sound familar to any Unix users?
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What is VFAT?
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Stands for "Virtual File Allocation Table." Older Windows operating systems (Windows ME and earlier) used a file system called "FAT" or "FAT32." The file system is what the operating system uses to organize and access files on the hard drive. VFAT, introduced with Windows 95, was an improvement to the basic FAT file system, allowing more information to be stored for each file. While the FAT file system can only store 8 characters for each file name, VFAT allows for file names up to 255 characters in length. Personally, I use the term VFAT to refer to the size of my cat.
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What is VGA?
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Stands for "Video Graphics Array." It is the standard monitor or display interface used in most PCs. Therefore, if a montior is VGA-compatible, it should work with most new computers. The VGA standard was originally developed by IBM in 1987 and allowed for a display resolution of 640x480 pixels. Since then, many revisions of the standard have been introduced. The most common is Super VGA (SVGA), which allows for resolutions greater than 640x480, such as 800x600 or 1024x768. A standard VGA connection has 15 pins and is shaped like a trapezoid.
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What is Viral Marketing?
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Viral marketing and viral advertising refers to marketing techniques that seek to exploit pre-existing social networks to produce exponential increases in brand awareness, through processes similar to the spread of an epidemic.
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What is Virtual Domain?
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Also seen as "redirecting URLs," a virtual domain is one that exists in type, but not on an actual server. Popular redirecting services (cjb.net, for example) will allow you to sign up for a virtual domain name of your choice. This is useful if your actual URL is long and not easily remembered. By typing in the redirecting URL of your choice, you are automatically redirected by the service to your actual, longer URL.
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What is Virtual Hosting?
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Virtual hosting is a method that web servers use to host more than one domain name on the same computer and IP address.
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What is Virtual Memory?
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Memory is hardware that your computer uses to load the operating system and run programs. It consists of one or more RAM chips that each have several memory modules. The amount of real memory in a computer is limited to the amount of RAM installed. Common memory sizes are 256MB, 512MB, and 1GB.
Because your computer has a finite amount of RAM, it is possible to run out of memory when too many programs are running at one time. This is where virtual memory comes in. Virtual memory increases the available memory your computer has by enlarging the "address space," or places in memory where data can be stored. It does this by using hard disk space for additional memory allocation. However, since the hard drive is much slower than the RAM, data stored in virtual memory must be mapped back to real memory in order to be used.
The process of mapping data back and forth between the hard drive and the RAM takes longer than accessing it directly from the memory. This means that the more virtual memory is used, the more it will slow your computer down. While virtual memory enables your computer to run more programs than it could otherwise, it is best to have as much physical memory as possible. This allows your computer to run most programs directly from the RAM, avoiding the need to use virtual memory. Having more RAM means your computer works less, making it a faster, happier machine.
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What is Virtual Reality?
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While the word "virtual" is typically overused in the computer world, it is aptly placed in the phrase "virtual reality." According to the American Heritage Dictionary, virtual means "existing or resulting in essence or effect though not in actual fact, form, or name." It can also mean "created, simulated, or carried on by means of a computer or computer network." Therefore, virtual reality is best described as an illusion of reality created by a computer system.
A person enters a world of virtual reality by putting on special glasses and headphones attached to a computer system running the virtual reality program. These devices immerse the user with the sights and sounds of the virtual world. Some virtual reality systems allow the user to also wear gloves with electronic sensors that can be used to touch or move virtual objects. As the user moves his head or hands, the computer moves the virtual world accordingly in real-time.
Virtual reality has been widely used for entertainment purposes, but the technology has found its way into the military and medical fields as well. While virtual reality systems have advanced significantly over the past decade, for the most part they are still more "virtual" than reality.
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What is Virus?
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Like a biological virus, a computer virus is something you don't want to get. Computer viruses are small programs or scripts that can negatively affect the health of your computer. These malicious little programs can create files, move files, erase files, consume your computer's memory, and cause your computer not to function correctly. Some viruses can duplicate themselves, attach themselves to programs, and travel across networks. In fact opening an infected e-mail attachment is the most common way to get a virus.
We all know it's hard enough to get a computer to work well when it is healthy, let alone when it has been attacked by a virus. Therefore, it is better to prevent an attack than to try and cure it. There are many anti-virus programs available that scan incoming files for viruses before they can cause damage to your computer. Some of these programs include Norton AntiVirus®, McAfee VirusScan®, and Virex®. It is a good idea to have one of these programs on your computer to prevent a virus attack. It is also important to update your virus definitions file at least once a month so that your anti-virus program can check for all the latest viruses. It's a lot like having a glass of orange juice every morning -- it keeps your computer's immune system strong and healthy.
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What is VLB?
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Stands for "VESA Local Bus." (VESA stands for "Video Electronics Standards Association"). The VLB, or VL-bus is a hardware interface on the computer's motherboard that is attached to an expansion slot. By connecting a video expansion card to the VLB, you can add extra graphics capabilities to your computer. The interface supports 32-bit data flow at up to 50 MHz. Though the VLB architecture was popular in the early 1990s, it has since been replaced by the newer and faster, but still three-lettered, ISA, PCI, and AGP slots.
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What is VoIP?
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Stands for "Voice Over Internet Protocol," and is often pronounced "voip." VoIP is basically a telephone connection over the Internet. The data is sent digitally, using the Internet Protocol (IP) instead of analog telephone lines. This allows people to talk to one another long-distance and around the world without having to pay long distance or international phone charges.
In order to use VoIP, you need a computer, an Internet connection, and VoIP software. You also need either a microphone, analog telephone adapter, or VoIP telephone. Many VoIP programs allow you to use a basic microphone and speaker setup. Others requires VoIP phones, which are like regular telephone handsets, but typically connect to your computer via USB. Analog telephone adapters allow you to use regular phones with your computer. IP phones are another option that connect directly to a router via Ethernet or wirelessly. These phones have all the necessary software for VoIP built in and therefore do not require a computer.
The largest provider of VoIP services is Vonage, but there are several other companies that offer similar services. While Vonage charges a monthly service fee, programs like Skype and PeerMe allow users to connect to each other and talk for free. However, these free services may offer fewer connections, lower audio quality, and may be less reliable than paid services like Vonage.
VoIP is also referred to as IP telephony, Internet telephony, and digital phone.
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What is Volume?
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The word "volume" has several different meanings. The most common definition is the magnitude or intensity of a certain sound. Volume may also refer to how much space a three-dimensional object takes up. However, in the always ambiguous realm of computers, the word volume can also refer to a specific data storage device.
Some examples of volumes include hard disks, DVD drives, and flash memory drives, such as USB keychain drives. Your computer recognizes all these data storage devices as volumes. The only requirement is that each volume has a file system that the computer can recognize. The file system tells the computer how the folders and files are organized on the volume.
On a Macintosh, all volumes connected to the computer (either directly or by a network connection) will show up on the desktop. For example, a hard drive will have a hard drive icon and a CD will have a CD icon. In Windows, you will find a list of all available volumes when you open "My Computer." If a volume is connected, but is not showing up on the screen, you can often use a disk utility program to "mount" the volume so that the computer can communicate with it.
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What is VPI?
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Stands for "Virtual Path Identifier." The VPI is an 8-bit header inside each ATM cell that indicates where the cell should be routed. ATM, or asynchronous transfer mode, is a method of sending data in small packets of fixed sizes. It is used by many ISPs (Internet Service Providers) for transferring data to client computers.
As an ATM cell moves across a network, it typically passes through several ATM switches. The VPI tells the switches where to route the packet of information, or what path to take. Hence the name, "virtual path identifier." The VPI is used in conjunction with the VCI, or virtual channel identifier
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What is VPN?
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Stands for "Virtual Private Network." (Not a competitor of UPN). This is a network term that most computer users don't need to know, but at least you can impress your friends by talking about it. A VPN refers to a network that is connected to the Internet, but uses encryption to scramble all the data sent through the Internet so the entire network is "virtually" private. For example, a large company that has offices in multiple locations may need to send data to the different locations via the Internet. To keep the information secure, the company might first set up a VPN with an encrypted connection. It's basically like having a secure Intranet over the Internet.
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What is VRAM?
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Stands for "Video Random Access Memory" and is pronounced "V-RAM." System RAM is great for loading and running programs, but when you need graphics power, VRAM is where it's at. This is the memory used to store image data that the computer displays; it acts as a buffer between the CPU and the video card. When a picture is to be displayed on the screen, the image is first read by the processor and then written to the VRAM. The data is then converted by a RAM digital-to-analog converter (RAMDAC) into analog signals that are sent to the display. Of course, the whole process happens so quickly, you don't notice it. Unlike most system RAM, VRAM chips are dual-ported, which means that while the display is reading from VRAM to refresh the currently displayed image, the processor is writing a new image to the VRAM. This prevents the display from flickering between the redrawing of images.
There are many different types of VRAM. One popular kind is called Synchronous Graphics RAM (SGRAM). It is an inexpensive type of RAM that is clock-synchronized. This means data can be modified in a single operation rather than as a sequence of read, write, and update operations. This allows background, foreground, and image fills to be handled more efficiently. Another type of VRAM is Rambus Dynamic RAM (RDRAM). It is designed by Rambus and includes a proprietary Rambus bus that speeds up the transfer of data through it. Video editing pros like this chip since it is optimized for video streaming. A third type of VRAM is Window RAM (WRAM). This high-performance VRAM is dual-ported, has about 25% more bandwidth than standard VRAM, and typically costs less. Finally, there is Multibank Dynamic RAM (MDRAM). This is also high-performance VRAM, developed by MoSys, which divides the memory into divisions of 32 KB that can be accessed individually. This makes memory transfers more efficient and increases overall performance. Another advantage of MDRAM is that it can be manufactured with just th
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What is VRML?
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Stands for "Virtual Reality Modeling Language." If you think this has something to do with HTML, you're right. While HTML is the format for Web page production, VRML is a 3D navigation specification, which enables the creation of interactive 3D Web sites. With VRML, visitors can take virtual tours through buildings and view three-dimensional models of cars directly from their Web browsers. Though the technology was created by Silicon Graphics and Intervista Software a number of years ago, it still is not widely used.
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