Infrared

Having a frequency in the electromagnetic spectrum in the range just below that of red light. Objects radiate infrared in proportion to their temperature. Infrared radiation is traditionally divided into four somewhat arbitrary categories based on its wavelength. See the table. Acronym: IR.

Updading Blog

Updating the blog www.compterms.blogspot.com

Fuzzy computing

1. A computing technique that deals with vague, incomplete, or ambiguous data in a precise mathematical way while providing solutions based on the human way of thinking. The term fuzzy relates to the type of data it processes, not to the technique itself, which is very exact. Fuzzy computing is also known as fuzzy set theory or fuzzy logic, and covers fuzzy control and fuzzy expert systems, for example. 2. A computing technology in which the computer interprets data by looking for patterns in problems while completing tasks. Using fuzzy computing, the computer is able to examine patterns in the data it receives and to make inferences based on that data, and act accordingly.

Statistics

The branch of mathematics that deals with the relationships among groups of measurements and with the relevance of similarities and differences in those relationships. See also binomial distribution, Monte Carlo method, probability, regression analysis, standard deviation, stochastic.

Relational calculus

In database management, a nonprocedural method for manipulating relations (tables). There are two families of relational calculus: domain calculus and tuple calculus. The two families of relational calculus are mathematically equivalent to each other and to relational algebra. Using either family, one can formulate a description of a desired relation, based on the existing relations in the database.

Thick film

A term describing a method used in the manufacture of integrated circuits. Thick film technology uses a stencil-like technique called photosilkscreening to deposit multiple layers of special inks or pastes on a ceramic substrate. The inks or pastes can be conducting, insulating, or resistive. The passive components (wires, resistors, and capacitors) of the integrated circuits are formed by depositing a series of films of different characteristics and patterns. Compare thin film.

Run-length limited encoding

A fast and highly efficient method of storing data on a disk (usually a hard disk) in which patterns in the bits representing information are translated into codes rather than being stored literally bit by bit and character by character. In RLL encoding, changes in magnetic flux are based on the number of zeros that occur in sequence. This scheme allows data to be stored with fewer changes in magnetic flux than would otherwise be needed for the number of data bits involved and results in considerably higher storage capacity than is possible with older technologies, such as frequency modulation (FM) and modified frequency modulation (MFM) encoding. Abbreviation: RLL encoding. Compare frequency modulation encoding, modified frequency modulation encoding.

Synchronous operation

1. Two or more processes that depend on the occurrences of specific events such as common timing signals. 2. A data transmission method in which there is constant time between successive bits, characters, or events. The timing is achieved by the sharing of a single clock. Each end of the transmission synchronizes itself with the use of clocks and information sent along with the transmitted data. Characters are spaced by time and not by start and stop bits. 3. A function call that blocks execution of a process until it returns. See also asynchronous operation.

Inherit

To acquire the characteristics of another class, in object-oriented programming. The inherited characteristics may be enhanced, restricted, or modified. See also class.

Static1

In information processing, fixed or predetermined. For example, a static memory buffer remains invariant in size throughout program execution. The opposite condition is dynamic, or ever-changing.

Tab character

A character used to align lines and columns on screen and in print. Although a tab is visually indistinguishable from a series of blank spaces in most programs, the tab character and the space character are different to a computer. A tab is a single character and therefore can be added, deleted, or overtyped with a single keystroke. The ASCII coding scheme includes two codes for tab characters: a horizontal tab for spacing across the screen or page and a vertical tab for spacing down the screen or page. See also Tab key.

Event property

A characteristic or parameter of an object that you can use to respond to an associated event. You can run a procedure or macro when an event occurs by setting the related event property.

Paintbrush

An artist’s tool in a paint program or another graphics application for applying a streak of solid color to an image. The user can usually select the width of the streak. See also paint program. Compare spraycan.

Eiffel#

Pronounced “Eiffel Sharp.” A subset language of Eiffel specifically designed to target the .NET Framework and embody the full extent of Design by Contract. See also Design by Contract.

Array

In programming, a list of data values, all of the same type, any element of which can be referenced by an expression consisting of the array name followed by an indexing expression. Arrays are part of the fundamentals of data structures, which, in turn, are a major fundamental of computer programming. See also array element, index1, record1, vector.

Time-synchronization service

A program used to ensure that all systems on a network use a common time. Time-synchronization services on the Internet typically update real-time clocks to Universal Time Coordinate (UTC) using Network Time Protocol (NTP). Windows Time Synchronization Service (Win32Time) is a time-synchronization service. See also clock (definition 2), Network Time Protocol, Universal Time Coordinate.

Internet

The worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, government, educational, and other computer systems, that route data and messages. One or more Internet nodes can go off line without endangering the Internet as a whole or causing communications on the Internet to stop, because no single computer or network controls it. The genesis of the Internet was a decentralized network called ARPANET created by the U.S. Department of Defense in 1969 to facilitate communications in the event of a nuclear attack. Eventually other networks, including BITNET, Usenet, UUCP, and NSFnet, were connected to ARPANET. Currently the Internet offers a range of services to users, such as FTP, e-mail, the World Wide Web, Usenet news, Gopher, IRC, telnet, and others. Also called: the Net. See also BITNET, FTP1 (definition 1), Gopher, IRC, NSFnet, telnet, Usenet, UUCP, World Wide Web.

Byte-oriented protocol

A communications protocol in which data is transmitted as a string of characters in a particular character set, such as ASCII, rather than as a stream of bits as in a bit-oriented protocol. To express control information, a byte-oriented protocol relies on control characters, most of which are defined by the coding scheme used. The asynchronous communications protocols commonly used with modems and IBM’s BISYNC protocol are byte-oriented protocols. Compare bit-oriented protocol.

Conceptual schema

In a database model that supports a three-schema architecture (such as that described by ANSI/X3/SPARC), a description of the information contents and structure of a database. A conceptual schema (also known as a logical schema) provides a model of the total database, thus acting as an intermediary between the two other types of schemas (internal and external) that deal with storing information and presenting it to the user. Schemas are generally defined using commands from a DDL (data definition language) supported by the database system. See also internal schema, schema.

Diskless workstation

A station on a computer network that is not equipped with a disk drive and that uses files stored in a file server. See also file server.

Descendent key

All the subkeys that appear when a key in the registry is expanded. A descendent key is the same as a subkey. Also called: descendant key. See also key, subkey.

Select

1. In general computer use, to specify a block of data or text on screen by highlighting it or otherwise marking it with the intent of performing some operation on it. 2. In database management, to choose records according to a specified set of criteria. See also sort. 3. In information processing, to choose from a number of options or alternatives, such as subroutines or input/output channels.

Full-motion video

Video reproduction at 30 frames per second (fps) for NTSC signals or 25 fps for PAL signals. Also called: continuous motion video. See also frame (definition 1). Compare freeze-frame video.

Defense Advanced Research Projects Agency

The U.S. government agency that provided the original support for the development of the interconnected networks that later grew into the Internet. Acronym: DARPA. See also ARPANET.

Raster display

A video monitor (typically a CRT) that displays an image on the screen as a series of horizontal scan lines from top to bottom. Each scan line consists of pixels that can be illuminated and colored individually. Television screens and most computer monitors are raster displays. See also CRT, pixel. Compare vector display.

Spamdexter

An individual who lures users to spam-related Web sites by loading the site with hundreds of hidden copies of popular keywords, even if those words have no relation to the Web site. Because the keywords appear so many times, the spamdexter’s site will appear near the top of search result and indexing lists. The term spamdexter was created by combining the words spam and index. Also called: keyword stuffing.

Telephony Service Provider Interface

The external interface of a service provider to be implemented by vendors of telephony equipment. A telephony service provider accesses vendor-specific equipment through a standard device driver interface. Installing a service provider allows Windows CE–based applications that use elements of telephony to access the corresponding telephony equipment. Acronym: TSPI. See also Telephony Service Provider.

Chaining

1. In computers, the linking of two or more entities so that they are dependent upon one another for operation. 2. In programming, the linking of two or more programs so that the first program causes the second program to begin executing. 3. In programming, linking program statements so that each statement, except for the first, relies on the previous statement for input. 4. With batch files, linking two or more batch files so that the completion of the first batch file causes the second batch file to begin executing. 5. With data storage, linking two or more individual units of storage. For example, a single file on a disk may actually be stored on several different sectors of the disk, each of which points to the next sector containing a piece of that file. These sectors are said to be chained together, or, more literally, to be a chain of clusters. 6. See daisy chaining.

Collision detection

1. The process by which a node on a local area network monitors the communications line to determine when a collision has occurred; that is, when two nodes have attempted to transmit at the same time. Although network stations usually avoid collisions by monitoring the line and waiting for it to clear before transmitting, the method is not foolproof. When a collision does occur, the two nodes involved usually wait a random amount of time before attempting to retransmit. See also contention, CSMA/CD. 2. The process by which a game or simulation program determines whether two objects on the screen are touching each other. This is a time-consuming, often complicated procedure; some computers optimized for graphics and games, such as the Amiga, have special hardware built in specifically to detect collisions.

AutoPlay

A feature in Windows 9x and later that allows it to automatically operate a CD-ROM. When a CD is inserted into a CD-ROM drive, Windows looks for a file called AUTORUN.INF on the CD. If the file is found, Windows will open it and carry out its instructions, which are usually to set up an application from the CD-ROM on the computer’s hard disk or to start the application once it has been installed. If an audio CD is inserted into the drive, Windows will automatically launch the CD Player application and play it.

End-to-end examination

An inspection of all of the processes and systems in place at an organization that affect the computer systems. The examination begins with the data or information that flows into the system, continues with how the data is manipulated and stored, and ends with how the data is output. For example, end-to-end examination is one technique that was employed to ferret out Year 2000 problems in computer systems of an organization.

Open2

To make an object, such as a file, accessible.

Source code control system

A tool designed to track changes made to source code files. Changes are documented in such a way that previous versions of the files can be retrieved. Source code control is used in software development, particularly in situations involving concurrent development and multiple user access to source code files.

Weighted code

A data representation code in which each bit position has a specified inherent value, which might or might not be included in the interpretation of the data, depending on whether the bit is on or off.

Wireless LAN

A LAN (local area network) that sends and receives data via radio, infrared optical signaling, or some other technology that does not require a physical connection between individual nodes and the hub. Wireless LANs are often used in office or factory settings where a user must carry a portable computer from place to place. Also called: WLAN.

POSIX

Acronym for Portable Operating System Interface for UNIX. An Institute of Electrical and Electronics Engineers (IEEE) standard that defines a set of operating-system services. Programs that adhere to the POSIX standard can be easily ported from one system to another. POSIX was based on UNIX system services, but it was created in a way that allows it to be implemented by other operating systems. See also service (definition 2).

Wireless Transaction Protocol

A lightweight request/reply transaction protocol for devices with limited resources over networks with low to medium bandwidth. It is not called the Wireless Transport Protocol or the Wireless Transfer Protocol. Acronym: WTP.

Worksheet

In a spreadsheet program, a page organized into rows and columns appearing on screen and used for constructing a single table.

Unpack

To restore packed data to its original format. Compare pack.

Username

The name by which a user is identified to a computer system or network. During the logon process, the user must enter the username and the correct password. If the system or network is connected to the Internet, the username generally corresponds to the leftmost part of the user’s e-mail address (the portion preceding the @ sign, as in username@company.com). See also e-mail address, logon.

Write2

To transfer information either to a storage device, such as a disk, or to an output device, such as a monitor or a printer. Writing is the means by which a computer provides the results of processing. A computer can also be said to write to the screen when it displays information on the monitor. See also output1. Compare read.

Fidonet

1. A protocol for sending e-mail, newsgroup postings, and files over telephone lines. The protocol originated on the Fido BBS, initiated in 1984 by Tom Jennings, and maintaining low costs has been a factor in its subsequent development. Fidonet can exchange e-mail with the Internet. 2. The network of BBSs, private companies, NGOs (nongovernment organizations), and individuals that use the Fidonet protocol.

Dynamic Data Exchange (DDE)

A method of interprocess communication within the Microsoft Windows operating systems.

Drive Letters

Single letters assigned as abbreviations to the mass storage volumes available to a computer. See also Volumes.

Electronic Mall (e-mail)

A type of client/server application that provides a rootexi, st<* \!rvs<.i,iv service between any two user e-mail accounts. E-mail accounts are not the same as user accounts, but j one-to-one relationship usually exists between them. Becausc all modern computers can attach to the Internet, users can send c-mail over the Internet to anv location that has telephone or »irviess digital Mr- vice. See also Internet.

Emergency Repair Disk

A floppy diskette created by the RDISK. EXE program that contains crit- ical Registry information about a Windows NT installation. With an emergency repair disk, a Windows NT installation can be salvaged using the restore option when re-installing from CD-ROM. See also Registry.

Environment Variables

Variables, such as the search path, that contain information available to programs and batch files about the current operating system environment.

Ethernet

The most popular data link layer standard for local area networking. Ethernet implements ihe carrier sense multiple access with collision detection (CSMA/CD) method of arbitrating multiple computer access to the same network. This standard supports the use of Ethernet over any type of media including wireless broadcast. Standard Ethernet operates as 10 megabits per second. Fast Ethernet oper- ates at 100 megabits per second. See also Data Link Layer.

Explorer

The default shell for Windows 95 and Windows NT 4.0. Explorer implements the more flexible desktop object paradigm rather than the Program Manager paradigm used in earlier versions of Windows. See also Desktop.

Fault Tolerance

Any method that prevents system failure by tolerating single faults, usually through hardware redundancy.

Fiber Distributed Data Interface (FDDI)

A data link layer that implements two counter- rotating token rings at 100 megabits per second. FDDI has been a popular standard for interconnecting campus and metropolitan area networks because it allows distant digital connections at high speed, but ATM is replacing FDDI in .iiany sites. See also Asynchronous Transfer Mode, Data Link Layer.

File Allocation Table (FAT)

The file system used by MS-DOS and available to other operating systems such as Windows (all variations), OS/2, and the Macintosh. FAT has become something of a mass storage compatibility standard because of its simplicity and wide availability. FAT has few fault tolerance features and can become corrupted through normal use over time. See also File System.

File System

A software component that manages the storage of files on a mass storage device by providing services that can create, read, write, and delete files. File systems impose an ordered database of files, called volumes, on the mass storage device. Volumes use hierarchies of directories to organize files. See also Mass Storage Device. Files. Database. Volumes, Directories.

File Transfer Protocol (FTP)

A simple Internet protocol that transfers complete files from an FTP server to a client running the FTP client. FTP provides a simple method of transferring files between computers, but cannot perform browsing functions. You must know the URl. of the FTP server to which you wish to attach. See also Internet, Uniform Resource Locator.

Frame

A data structure that network hardware devices use to transmit data between computers.

Gateway

A computer that serves as a router, a format translator, or a security filter for an entire network.

Global Group

Group accounts maintained by the primary dom.iincrmrroller and visible to all com- puters in the domain. A global group can contain only members from within its domain. See also Local Group, group indentifier.

Graphical Device Interface (GDI)

The programming interface and graphical services provided to Win32 for programs to interact with graphical devices such as the screen and printer. See also Pro- gramming Interface, Win32.

Graphical User Interface (GUI)

A computer shell program that represents mass storage devices, directories, and files as graphical objects on a screen. A cursor driven by a pointing device such as a mouse manipulates the objects. Typically, icons that can be opened into windows that show the data contained by the object represent the objects. See also Shell, Explorer.

Group Identifiers

Security identifiers that contain the set of permissions allowed to a group. When a user account is part of a group, the group identifier is appended to that user's security identifier, thus granting the individual user all the permissions assigned to that group. See also Security Identifier, Accounts, Permissions.

Groups Security

entities to which users can be assigned membership for the purpose of applying the broad set of group permissions to the user. By managing permissions for groups and assigning users to groups, rather than assigning permissions to users, security administrators con keep coherent control of very large security environments. See also Permissions, Accounts, Security Local Group, Global Group.

Hard Disk Drives

Mass storage devices that read and write digital information magnetically on disks that spin under moving heads. Hard disk drives are precisely aligned and cannot normally be removed. Hard disk drives are an inexpensive way to store gigabytes of computer data permanently. Hard disk drives also store the installed software of a computer. See also Mass Storage Device.

Hardware Abstraction Layer (HAL)

A Windows NT service that provides basic input/output services such as timers, interrupts, and multiprocessor management for computer hardware. The HAL is a device driver for the motherboard circuitry that allows the Windows NT operating system to treat dif- ferent families of computers the same way. See also Driver, Service, Interrupt Request.

Computer Name

 A 1- to 15-character NetBIOS name used to uniquely identify a computer on the network. See also Network Basic Input/Output System.

Exchange

Microsoft's messaging application. Exchange implements Microsoft's mail application programming interface (MAPI) as well as other messaging protocols such as POP, SNMP, and faxing to provide a flexible message composition and reception service. See also Electronic Mail, Fax Modem.

Icon

A graphical representation of a resource in a graphical user interface that usually takes the form of a small (32 x 32) bitmap. See also Graphical User Interface.

Host An Internet Server

Hosts are constantly connected to the Internet. See also Internet.

Hyperlink

A link in text or graphics files that have a Web address embedded within them. By clicking the link, you jump to another Web address. You can identify a hyperlink because it is a different color than the rest of the Web page. See also World Wide Web.

Industry Standard Architecture (ISA)

The design standard for 16-bit Intel compatible motherboards and peripheral buses. The 32/64-bit PCI bus standard is replacing the ISA standard. Adapters and interface cards must conform to the bus standard(s) used by rhe motherboard in order to be used with a computer.

Computer

A device capable of performing automatic calculations based upon lists of instructions called programs. The computer feeds the results of these calculations (output) to peripheral devices that can represent them in useful ways, such as graphics on a screen or ink on paper. See also Microprocessor.

IDE

A simple mass storage device interconnection bus that operates at 5Mbps and can handle no more than two attached devices. IDE devices are similar to but less expensive than SCSI devices. See also Small Computer Systems Interface, Mass Storage Device.

Driver

A program that provides a software interface to a hardware device. Drivers arc written for the specific device they control, but they present a common software interface to the computer's operating system, allowing all devices (of a similar type) to be controlled as if they were the same. See also Data Link Layer, Operating System.

Files

A set of data stored on a mass storage device identified by a directory entry containing a name, file attributes, and the physical location of the file in the volume. See also Volume, Mass Storage Device, Directory, File Attributes.

Firmware

Software stored permanently in nonvolatile memory and built into a computer to provide its BIOS and a bootstrap routine. Simple computers may have their entire operating system built into firmware. See also BIOS, Boot, Software.

Format

The process of preparing a mass storage device for use with a file system. Low-level format- ting writes a structure of sectors and tracks to the disk with bits used by the mass storage controller hardware. The controller hardware requires this format, and it is independent of the file system. High- level formatting creates file system structures such as an allocation table and a root directory in a parti- tion, thus creating a volume. See also Mass Storage Device, Volume.

Hyperlink

A link in text or graphics files that have a Web address embedded within them. By clicking the link, you jump to another Web address. You can identify a hyperlink because it is a different color than the rest of the Web page. See also World Wide Web.

Compact Disk-Read-Only Memory (CD-ROM)

A media for storing extremely large software packages on optical read-only discs. CD-ROM is an adaptation of the CD medium used for distrib- uting digitized music. CD-ROM discs can hold up to 650MB of information and cost very little to produce in mass quantity. See also Hard Disk Drive.

Control Panel

A software utility that controls the function of specific operating system services by allowing users to change default settings for the service to match their preferences. The Registry contains the Control Panel settings on a system and/or per user basis.

Cooperative Multitasking

A multitasking scheme in which each process must volantarily return time to a central scheduling route. If any single process fails to return to the central scheduler, the computer will lock up. Both Windows and the Macintosh operating systems use this scheme. Sec also Pre- emptive Multitasking, Windows for Workgroups

Administrative Tools

 Program group on Windows NT servers that contain utilities such as User Manager for Domains, Server Manager, Disk Administrator, Performance Monitor, and Network Mon- itor. See also I'ser Manager for Domains, Server Manager, Disk Administrator, Performance Monitor, Network Monitor.

Binding

The process of linking network services to network service providers-. The binding facility allows users to define exactly how network services operate in order to optimize the performance of the system. By default, Windows enables all possible bindings. You can use the Network control panel to change bindings.

File Transfer Protocol (FTP)

A simple Internet protocol that transfers complete files from an FTP server to a client running the FTP client. FTP provides a simple method of transferring files between computers, but cannot perform browsing functions. You must know the URL. of the FTP server to which you wish to attach. See also Internet, Uniform Resource Locator.

Gateway Services for NetWare (GSNW)

An NT Server service that connects NT Servers and NT clients to NetWare resources via the gateway software. See also Gateway, NetWare, Client Services for NetWare.

COM Port Communications port.

A serial hardware interface conforming to the RS-232 standard for low-speed serial communications. See also Modem, Serial.

Access Tokens

Objects containing the security identifier of a running process. A process started by another process inherits the starting process's access token. The access token is checked against each object's ACL to determine whether or not appropriate permissions are granted to perform any requested service. See also Access Control List, Access Control Entries, Permissions. Object, Security Identifier, Process.

Address Resolution Protocol (ARP)

 An Internet protocol for resolving an IP address into a physical layer address (such as an Ethernet media access control address). See also Physical Layer, Internet Protocol.

Database

A related set of data organized by type and purpose. The term also can include the application software that manipulates the data. The Windows NT Registry (a database itself) contains a number of utility databases such as user account and security information.

File Attributes

File Attributes
Bits that show the status of a file (e.g.. archived, hidden, read-only) are stored atone with the name and location of a file in a directory entry. Different operating systems use different tile attributes to implement such services as sharing, compression, ami security.

Domain Controllers

Domain Controllers
Servers that authenticate workstation network logon requests by comparing a username and password against account information stored in the user accounts database. A user cannot access a domain without authentication from a domain controller. See also Primary Domain Controller, Backup Domain Controller, Domain.

Browser

Browser
A computer on a Microsoft network that maintains a list of computers and services available on the network.

Account Lockout

Account Lockout
Used to specify how many invalid logon attempts should be tolerated before a user account is locked out. Account lockout is set through User Manager for Domains.

Write-Back Caching

 A caching optimization wherein data written to the slow store is cached until the cache is full or until a subsequent write operation overwrites the cached data. Write-back caching can significantly reduce the write operations to a slow store because many write operations are subsequently obviated by new information. Data in the write-back cache is also available for subsequent reads. If something happens to prevent the cache from writing data to the slow store, the cache data will be lost.

Windows Internet Name Service (WINS)

 A network service for Microsoft networks that provides Windows computers with Internet numbers for specified NetBIOS names, facilitating browsing and intercommunication over TCP/IP networks.

Ethernet

The most popular data link layer standard for local area networking. Ethernet implements the carrier sense multiple access with collision detection (CSMA/CD) method of arbitrating multiple computer access to the same network. This standard supports the use of Ethernet over any type of media including wireless broadcast. Standard Ethernet operates as 10 megabits per second. Fast Ethernet operates at 100 megabits per second

Swap File

The virtual memory file on a hard disk containing the memory pages that have been moved out to disk to increase available RAM

Universal Naming Convention.(UNC)

 A multivendor, multiplatform convention for identifying shared resources on a network.

Access Control Entries

Access Control Entries
ACLs for objects contain access control entries, each of which describes a specific permission for a specific service for a user or a group

Access Control Lists

Access Control Lists

Each object has an ACL attribute that describes which user or group accounts have access to the object and what type of access they have. If a user does not have an entry in the ACL allowing access to a service of an
object, Windows NT will