tablet than previous tablet-based computers, it includes handwriting recognition as well as the ability to retain handwritten words and annotations without turning them into computer text. This latter ability is known as “rich digital ink,” because the inking (writing, drawing, scribbling) is stored as a graphic algorithm after smoothing out rough edges. See tablet computers. (2) (tablet PC) Any tablet-based computer, including those prior to Windows XP-based models. U UDP UDP (User Datagram Protocol) is a protocol that runs over IP networks, like
TCP. But unlike TCP/IP, UDP/IP provides very little error recovery service, and instead provides a direct way to send and receive data over an IP network. UDP is widely used for transmitting messages over a network. ULSI ULSI (ultra large scale integration) refers to the way more than one million circuit elements are placed on a chip. Intel's 489 and Pentium microprocessors, for example, used ULSI technology. Unicode Unicode is the standard for representing characters as integers. Unlike ASII which
uses 8 bits for each character, Unicode uses 16 bits which can be used to represent more than 65,000 characters. uniform resource locater View URL universal resource locater View URL Universal Serial Bus See USB UNIX
UNIX is an operating system that supports multi-user and multitasking that was developed at Bell Labs in the early 1970s. UNIX was one of the first operating systems written in a level programming language, namely C. Bell Labs distributed this operating system with its source code so that it could be changed and adapted to specific needs. By the late 1970s there were many versions of UNIX. In 1982, AT&T began marketing UNIX. Because of the large number of versions available, it was difficult to create a standard version of UNIX. Until now, there are two types of UNIX on the market: one produced by AT&T known as System V and the other developed by Berkeley University and known as BSD4.x (x=1, 2, 3).
Because of its portability, flexibility, and robustness, UNIX became the operating system of choice for workstations. Linux is another version of UNIX that is widely used for PCs. Unshield Twisted Pair SeeUTP. Upgrades Upgrades are programs released to improve the capabilities of previous programs. Many software companies regularly improve the capabilities of their software products by adding new features and functions
Upload Upload is the transfer of data via digital communication lines from a smaller system (client) or peripheral to a larger and central system (host). The opposite of uploading is downloading. Upward compatible The term upward compatible refers to the compatibility of a product with newer models or versions. For example, a program designed on an Intel 486 microprocessor can also run on a Pentium microprocessor. This type of compatibility is important. because it means that newer computers with better capabilities can be used without converting the data. The opposite of upward compatible (which is also called forward compatible) is
backward compatible, but from the perspective of newer models. URLs A uniform resource locator or universal resource locator URL is an internet address. The internet address is translated from general to specific (such as when calling, starting from country code, area code and telephone number). An example URL is http://www.microsoft.com/info/index. USB USB Universal Serial Bus is a standard port used to connect external devices (such as digital cameras, scanners and
mice) to computers with Windows 98 or Macintosh. Standard USB supports transmission speeds of up to 12 Mbps. USB devices can also be connected or removed without restarting the computer. Usenet Usenet is a worldwide network of thousands of Unix systems with decentralized administration. The Usenet system is used to transmit messages to newsgroups on specific topics. Users View users.
User Datagram Protocol See UDP. User Interface View user interface. User name User name is a unique name for each user of a computer service that can be accessed by many users, such as a computer network or e-mail service. Users of this service must identify themselves to enter the system for security, recording and resource management purposes. Usually, apart from entering a username, a user must also enter a password.
Utility Utilities are programs that perform very specific tasks, usually related to managing system resources. The operating system consists of a number of utilities for managing disk drives, printers, and other devices. Utilities differ from applications in terms of size, complexity, and functionality. For example, word processing programs, spreadsheet programs, and database applications are included as applications because they have various functions and are not directly related to managing system resources. Utilities are sometimes installed as memoryresident programs. Calendars, calculators, and spell check are some examples.
UTP UTP (Unshielded Twisted Pair) is a type of cable that consists of two twisted unwrapped wires. UTP cables are widely used in local-area networks (LANs) and telephone connections because they are cheaper. UTP cables are not as good as coaxial and fiber optic cables in terms of providing bandwidth and resistance to interference. UPS (Uninterruptible Power Supply) A device that provides battery backup when the electrical power fails or drops to an unacceptable voltage level. Small UPS systems provide power for a few minutes;
enough to power down the computer in an orderly manner, while larger systems have enough battery for several hours. In mission critical data centers, UPS systems are used for just a few minutes until the electrical generators take over. UPS systems can be set up to alert file servers to shut down in an orderly manner when an outage has occurred, and the batteries are running out. Surge Suppression and Voltage Regulation A surge protector filters out surges and spikes, and a voltage regulator maintains uniform voltage during a brownout, but a UPS keeps a computer running when there is no electrical power. UPS systems typically provide surge suppression and may provide voltage regulation. Standby and Line Interactive A standby UPS, also called an “offline UPS,” is the most common type of UPS found in a computer
or office supply store. It draws current from the AC outlet and switches to battery within a few milliseconds after detecting a power failure. The line interactive UPS “interacts” with the AC power line to smooth out the waveforms and correct the rise and fall of the voltage. Online UPS The online UPS is the most advanced and most costly UPS. The inverter is continuously providing clean power from the battery, and the computer equipment is never receiving power directly from the AC outlet. However, online units contain cooling fans, which do make noise and may require some location planning for the home user or small office. All UPS systems switch to battery when the power fails. The difference is how they handle the power under normal circumstances. Standby units provide limited attenuation whereas line interactive systems will
adjust the voltage and smooth out bad harmonics. Online systems are constantly regenerating clean power. (Diagrams courtesy of MGE UPS SYSTEMS.) umount /mnt/floppy Upload a diskette. The /mnt/floppy directory must not be the active directory. V Variable A variable is a data object in a computer program whose value can be changed. Each variable has three attributes, namely name, type, value. A variable name is an identifier determined by the programmer.
The variable type determines the data type of the value it has or is attached to. VAX The VAX (Virtual Address eXtensio) is the most successful microcomputer design in the history of the industry, after its predecessor the PDP-11. The VAX system uses the VMS (Virtual Memory System) operating system which supports virtual memory. VAX was introduced in 1977 by DEC and was successful and widely used until the mid-1980s, until the emergence of RISCbased workstations, including Alpha which was also developed by DEC.
Despite this, DEC still sold the VAX, but as a server and not as a minicomputer. VBScript Visual Basic Scripting Edition (VBScript) is a programming language developed by Microsoft to create scripts (small programs) that can be combined on HTML Web pages. This script can make the Web more interactive. VBScript can also be run with Microsoft ActiveX Controls which make it possible to create forms, interactive multimedia, games and other Web-based programs. VBScript functions similarly to JavaScript and is part of the Visual Basic programming language. VBX
VBX (Visual Basic Custom Control) is a software module that can be used in several different applications. VBX, which was originally created to help develop Windows applications with the help of Visual Basic, can be used in other environments. VBX is being replaced by a more flexible ActiveX control. Veronica Veronica (Very Easy Rodent Oriented Netwide Index to Computerized Archives) is a network utility used to search Gopher servers worldwide for specific keywords. This search includes more than 10 million items on more than 6,000 Gopher servers. Veronica can also display Gopher menu lists and articles containing the keywords used to search.
Vertex Vertex is the vertex of a graph. Vertices are also called nodes. Usually depicted as a small circle. Very Small Aperture Terminal See VSAT. VESA VESA (Video Electronics Standards Association) is a consortium of video adapter and monitor manufacturing companies that standardizes video protocols. VESA has developed video standards that can provide better
resolution and more colors than VGA. The standard is called SuperVGA (SVGA). Vestigial side band See VSB. VGA VGA (Video Graphics Array) is a graphics system for PCs developed by IBM. VGA is one of the PC standards. In text mode, the VGA system produces a resolution of 720 x 400 pixels. In graphics mode, it can produce a resolution of 640 x 480 (with 16 colors) or 320 x 200 (with 256 colors). The entire palette consists of 262,114 colors.
VGA uses analog signals so previously designed monitors that use digital signals cannot use VGA. Since its introduction in 1987, there have been several other standards that provide better resolution and more colors. Now, all PCs support VGA. vi vi is an editor developed by Bill Joy for the initial release of BSD. vi became the standard Unix editor and was a favorite before the emergence of another editor, Emacs, in 1984. Video bandwidth
The term video bandwidth refers to the ability to refresh the screen. The greater the bandwidth, the more information that can be displayed in a certain time span. On the other hand, low bandwidth will cause screen flickering, artifacts and ghosting to appear. To calculate the monitor bandwidth (measured in megahertz, MHz). Multiply the vertical resolution and the horizontal resolution of the screen, and then multiply the result by the refresh rate. For example, 800 x 600 x 75 = 36 MHz. Video Electronics Standards Association See VESA.
Videos for Windows Video for Windows (VFW) is a multimedia technology that is part of Windows 95. VFW files have the .avi extension and can be played with Windows Media Player. Because these files are large, they are often compressed using codecs. VFW is a video technology used on PCs, besides MPEG and QuickTime. Video Graphics Array See VGA. Viewer
Viewer helps the Web browser handle files that the browser cannot handle. The viewer can be a variety of applications depending on the file being handled, including sound files. Because it is a bit strange to use the term viewer to handle sound, it is often called a helper. Virtual local-area network See VLANs. Virtual memory Virtual memory is a part of the hard disk called the swap file, which is used to store data that is not used much in RAM. To do this, you need a virtual memory manager (one of the operating system functions)
which maps data or code to something other than RAM. Virtual private networks See VPN. Virtual reality Virtual reality is an artificial environment created with computer hardware and software and presented to users in a way that looks like it is real. To enter virtual reality, users wear special gloves, earphones and special glasses to interface with the computer system.
In this way, a minimum of three senses are controlled by the computer. For a better experience, virtual reality devices also monitor user activities. For example, special glasses (google) track how the user's eyeballs move and respond by sending new video input. The term virtual reality is sometimes used more generally to refer to a virtual world represented on a computer, even though it is only based on text and graphic representation. Virtual Reality Modeling Language See VRML.
Virtual servers A virtual server is a server, usually a Web server, that shares computer resources with other virtual servers. In this case, the computer used as a server is not specifically used to run server software. Virtual Web servers are the cheapest way to web hosting services. In this way, multiple virtual servers can exist on the same computer. However, if there are too many virtual servers on the same computer, or if a virtual server uses a lot of resources, then Web pages will be delivered more slowly.
Virtual software libraries SeeVSL. Virus A virus is a program that finds and infects other programs by copying itself into them. When an infected program is executed, the virus is also executed, which allows the virus to reproduce itself again in other programs. This process is not visible to the user. The damage caused by this virus varies, from just displaying funny messages to deleting files on the computer.
Visual basic Visual Basic is a high-level programming language from Microsoft that is graphically oriented and relatively easy to learn. Visual Basic can be used to create simple database applications to commercial software packages. Visual C++ Visual C++ is an application development tool developed by Microsoft intended for C++ programmers. Visual C++ supports object-directed programming for 32-bit applications in the Windows environment. Visual C++ also includes an integrated development environment (IDE), a C/C++ compiler, and a class library called Microsoft Foundation Classes (MFC). The IDE consists of AppWizard, ClassWizard,
testing features that make programming easier. Visual C++ was first released in 1993. Visual Interfaces See vi. VLANs VLAN (virtual local-area network) is a computer network that appears to be connected using the same cable even though it may be physically located on another part of the LAN. VLANs are configured via software and not hardware, which makes them very flexible.
One of the advantages of VLANs is that if a computer is physically moved to another location, the computer remains on the same VLAN without reconfiguring the hardware. VL-Bus VL-Bus (VESA Local-Bus) is a local bus architecture created by the Video Electronics Standards Association (VESA). Another local bus architecture on the market is PCI. VLSI VLSI (very large scale integration) refers to the way 100,000 to 1000,000 circuit elements are placed on a chip. now, almost
all chips use VLSI or ULSI (ultra large scale integration) architecture. VOC VOC is an audio file format developed by Creative Labs that was used with early Sound Blaster cards running on the DOS operating system. VOI VOI (Voice over the internet) is another name for internet telephony. See internet telephony. VoIP
VoIP (Voice over Internet Protocol) is another name for internet telephony. See internet telephony. VPN VPN (virtual private network) is a private internet connection that is secure and encrypted to ensure that only authorized users can access it and data transfers cannot be interfered with. VRML VRML (Virtual Reality Modeling Language) is a 3-dimensional (3D) navigation specification. VRML allows the creation of 3D sites.
VSAT VSAT (Very Small Aperture Terminal) is an earth station used in data, voice and video signal communication satellites, except for television broadcasting. VSAT consists of two parts: a transceiver that is placed in the open so that it can directly receive signals from satellites and a device that is placed indoors to connect the transceiver and end user communication devices, such as a PC. The transceiver receives and sends signals to satellite transponders in outer space. Satellites send and receive signals from ground station computers that serve as the system hub. Every user connected to the hub station passes through satellites, forming a star topology. The hub controls
all operations on the network. All transmissions for communication between users must pass through the hub station which forwards them to the satellite and to other VSAT users. VSAT can transmit data at speeds up to 56 Kbps. VSB VSB (vestigial side band) is a digital frequency modulation technique used to send data over networks that use coaxial cables. This technique is faster than the QPSK technique, but more sensitive to interference (noise). VSL
VSL (virtual software library) is a technology that makes it easier to find files to download from the internet. This technology consists of two elements: a back end that updates a database of downloadable files (shareware, freeware, and other corporate software archives) from the internet, and a front-end that makes this database easier to search and download. W W3C The W3C world wide web consortium is the body for the world wide web. The W3C works with the global community to
create international client and server standards that enable online commerce and communication over the internet. The W3C also produces reference software. W3C was founded by the Massachusetts Institute of Technology (MIT) on October 20, 1994. Netscape Communications Corporation was one of its founding members. This consortium is run by MIT LCS, INIRA National Institute of Research and Informatique, a French computer science research institute, in collaboration with CERN Consei Europpen pour le Recherce Nucleaire, the birthplace of the Web. The W3C is funded by its member industries, but its products are available free of charge. The director of the W3C is tim Berners-Lee who discovered the world wide web at CERN.
WAIS WAIS wide area information servers are a software system used to search indexed databases on remote servers. WAIS produces an ordered list of pages or files that can be retrieved from the server. One of the advantages with WAIS is the possibility of using natural language instead of using boolean operators. Real time Real time real time is a term used to describe a number of computer features. For example, a real-time operating system is a system that can respond to input immediately after it is given. This term also refers to events that are simulated by a computer at the same speed as the real world. In graphic animation, for example,
a real-time program will display moving objects on the screen at the same speed as in the real world. In databases, a time database is a database that stores data exactly as it is in the real world from time to time. Wallpapers Wallpaper is a background pattern used on a computer screen in the Microsoft Windows graphical user interface. WAN WAN wide area network is a network of computers that are connected in distant places and are connected by telephone
lines or radio waves. See also LAN and network. WAV WAV is the Windows standard for waveform sound files. WAV files usually have extensions. wav. Waveform Waveform is a type of sound that works like a tape recorder: sound can be recorded using a computer microphone. usually saved in WAv, AIFF, or AU format. Wavelength division multiplexing See WDM1.
WBS WBS Work Breakdown Structure is the division of a project into smaller activities. These activities are given an identity (for example given a number) to determine the relationship between the activities. WBS is very useful for project planning, especially if estimates of work time and resources used are required. WDM1 WDM wavelength division multiplexing is a multiplexing technique developed for use on optical fibers. WDM modulates each data stream into a different light spectrum. WDM can be called the optical
version of FDM frequency division multiplexing. WDM2 WDM Windows Driver Model is a driver technology developed by Microsoft to create drivers compatible with Windows 98, 2000, Me and XP. WDM works by channeling some of the device driver's work into a piece of code that is integrated into the operating system. The code sections handle all lower level buffer management, including DMA Direct Memory Access and plug and play devices. All versions of windows after windows 95 have implemented WDM. Kernel mode drivers that follow WDM rules are called WDM drivers.
Web portal A web portal is a Web site or service that offers a variety of resources and services. Such as e-mail, forums, search engines, and online shopping places. The first Web portals were online services, such as AOL and MSN, that provided access to the Web, but now many traditional search engines are being converted into Web portals to attract more users. Web servers A web server is a computer that delivers Web pages. Every Web server has an IP address and name. A computer can be used as a Web server by installing server software and connecting it to the internet. There is a lot of server software, both free, such as those made by NCSA and Apache,
and commercial ones, such as those made by Microsoft and Netscape. Webmasters A webmaster is a person in charge of maintaining a website. These tasks include writing HTML files, creating and managing more complex programs, and responding to incoming e-mail. WECA WECA Wireless Ethernet Compatibility Alliance http://www.wi-fi.org. is an organization consisting of companies making wireless equipment and software that aims to ensure the interoperability of
Wi-Fi products and promote Wi-Fi as a global wireless LAN standard. Weighted graph View weighted graph. Wide area information servers See WAIS. Wide area network See WAN. Wi-Fi
Wi-Fi Wireless Fidelity is the official trade name for IEEE 802.11b created by the Wireless Ethernet Compatibility Alliance (WECA). The term Wi-Fi replaced 802.11b just as the term Ethernet replaced IEEE 802.3. Products certified by WECA as Wi-Fi can operate together even though they are made by different companies. Windows Windows is a family of operating systems for PCs. The Windows operating system was developed by Microsoft and is used by most PCs in the world. Windows provides a graphical user interface (GUI), virtual memory management, and supports many peripheral devices. The Windows operating system family includes Windows 3.x. Windows 95, Windows NT,
Windows 2000, and the latest (2001) is Windows XP. Windows 2000 Windows 2000, often abbreviated as W2K, is an operating system released by Microsoft. There are 4 versions of Windows 2000: * Professional, which is an operating system intended for business desktop and laptop systems, which is used to run applications, internet and internet connections, access printer files, and other network resources. * servers used for Web servers and office servers. Windows 2000 server allows users to build Web applications and connect to the internet. * Advanced server, namely the operating system used for line of business and e-commerce applications. This system consists of functions found in the standard version of Windows 2000 server, plus additional features for applications that require a high level of scalability and availability. * Datacenter
Server, which is developed for use on computer networks with heavy traffic, which is needed by companies that need very reliable drivers and software. Windows 95 Windows 95 is an operating system released by Microsoft which was released in 1995. Windows 95 has quite important differences from its predecessor, Windows 3.1. Apart from supporting the new interface, Windows 95 also supports 32 bit applications, which means applications specifically made to run on this operating system will run faster. Although Windows 95 can run previous Windows and DOS applications. Windows 95 was not based on the DOS platform. Therefore, the limitations that exist in DOS are lost, such
as 640K main memory and a file naming system with 8 characters. Windows 98 Windows 98 is an operating system developed by Microsoft and released in 1998. This operating system was initially named Memphis and then Windows 97. But because this system was released rather slowly, the name was changed to Windows 98. Windows 98 offers support for a number of new technologies, including FAT32, AGP, MMX, USB, DVD, and ACPI. This operating system is also integrated with a Web browser (Internet Explorer). This feature makes it easy for users to access documents on a local hard disk or Web server.
Windows CE Windows CE is a Windows operating system designed for small devices such as personal digital assistants, PDAs or handled PCs. The Windows CE interface is similar to Windows 95, so devices running on Windows CE are easy to operate by people who are used to using Windows 95. Windows Driver models See WDM2. Windows Metafile Format See WMF.
Windows NT Windows NT Windows New Technology is a version of the Windows operating system. Windows NT is a 32 bit operating system that supports preemptive multitasking. There are two versions of Windows NT: Windows NT servers, which are designed as network servers, and Windows NT workstations for standalone PCs or work stations. Windows XP Windows XP is an operating system that was introduced in 2001. Microsoft considers this operating system to be its most important product after Windows 95. This system, which offers a new interface, is built on the Windows 2000 kernel and provides users with a more stable and