Saturday, October 3, 2009

A TO Z OF COMPUTER DICTIONARY

A TO Z OF COMPUTER DICTIONARY
A
ABACUS: One of the earliest known calculating devices on which rows of beads on wires are used to perform mathematical operations
Actuator: A device used to carry out the physical requirement of computer.
Algorithm: A sequence of instructions used to solve a given problem.
Alphanumeric Data Field: A unit of information in a record which may contain any kind of data – numbers , letters, or special symbols.
ANALOGUE: A way of representing data as a continuous , smoothly varying signal wave. Contrast with digital.
Analogue to Digital Converter(A/D Converter): A device that changes analogue data to digital data so that it can be stored and processed in a computer system.
ANALYTICAL ENGINE: An invention by Charles Babbage that incorporated several ideas used by computers today such as memory and punched cards.
AND gate: The AND gate will only output a high signal if it receives both input signals as high.
Application Software: Software used to manipulate input data in other to provide users with meaningful information . Contrast with system software.
Arithmetic and Logical Unit(ALU): A component of the CPU that performs arithmetic functions such as addition, subtraction, and logic functions such as the comparison of two numbers.
Artificial Intelligence: An expert system that can change the rules by which it works according to experience of what has happened previously.
ASCII: Acronym for American Standard Code for Information Interchange (pronounced ass-key). A binary code for representing data in many computers and for transmitting data over communication lines.
Assembler: A program that translates assembly language statements into machine language.
Assembly Language: A programming language that each individual operation is translated into a machine instruction ; it is very efficient , but it is a very difficult programming language to write.
Auxiliary storage; A series of devices that store data in electronic form so that the data can conveniently be used again; also called secondary storage. Example of auxiliary storage are floppy or hard disk for micros.

B
Babbage Charles: The father of computers; he design the difference engine and the analytical engine.
Back up file: a copy of file of information that is stored somewhere away from the computer and can be used to restore the file if the file is lost.
Bandwidth: a measurement of how much data can be sent along a communication channel at the same time.
Bar code: Black and white bars that we see on most books and consumer goods. They can be read by a Bar Code Reader or Light pen.
BASIC: An easy to learn high level programming language that is most often used for interactive processing; an acronym for Beginners All – purpose Symbolic Instruction Code.
Batch OS: An operating system in which the data to be processed is collected in batches and is then run at some later more convenient time; the data must not be time sensitive.
Binary Numbering System: A numbering system in which there are only two possible digits 0 and 1. Computers use a binary coded system for representing data and instructions.
Bit: means Binary digits. Is the smallest unit of a computer memory.
Black box: It is used with reference to gates, describing the flow of pulses in a particular direction.
Boot: Act of starting a computer by loading part of the operating system
Boolean data: Data that can only exist in two states and hence can be represented by 0 and 1.
Buffer: An area of memory outside the processor that allows the temporary storage of data while it is waiting to be used.
Bug: An error in a program
Byte: Eight adjacent bits of memory treated as a unit of information.

C
C: An high level programming language
Cathode ray tube( CRT): A TV like screen that displays user instructions and the computer responses: also called video display terminal (VDT) or monitor.
Central Processing Unit (CPU): The part of the computer system that controls all the computer operation.
Changeover: The process by which a new system replaces the old one; typical methods are direct changeover, phased implementation and parallel running.
Closed System: A computer system or network of computers that has no connections to external system such as the internet
COBOL: A High level language developed for business application; acronym of Common Business Oriented Language.
Coded data: Data that has been changed in some way so that entry and storage in the computer are simplified e.g. M for Male and F for Female.
Coding: The process of writing program or set of instruction that computer understands to solve a particular task.
COLOSSUS: Computer used by the British to crack the secret code used by Germany to send messages.
COM: Compute Output Microfilm: A device that can be linked to a CPU to create output on microfilm or microfiche at very high speeds.
Command: These are instructions given to the computer to perform.
Command based interface: Interface between the computer and the user that requires the user to type commands at a prompt supplied by the operating system.
Compiler: A program used to translate a source program into object program.
Computer: Is an electronic machine or device which accept data, process it and send the output to the screen as information.
Computer aided design (CAD): Software that allows design work to be carried out on a computer.
Computer aided learning (CAL): Using computers to teach students facts about a particular topic, it can also be used for testing students and automatically producing the result.
Computer aided manufacturer: software that allows the manufacture of items which have been design using CAD.
Computer educators: These are people who teach computing at various levels.
Computer managers: A computer professional who oversees the activities of all systems analysts and programmers in an organisation.
Computer professional: Person that has undergone one form of professional training or the other.
Computer system: A group of machines commonly called hardware, that together with programs called software, and put together by people called peopleware.
Cursor: A small blinking underline or rectangle that indicates where your input will actually appear on the screen.
Custom written software: Software that is specially commissioned to carry out a particular task.

D

Data: An unprocessed information stored on the computer.
Data dictionary: a list that stores details of data items in a database.
Data encryption: Encoding data so that it cannot be understood unless it is first decoded used to protect data from unauthorised access.
Data entry: Entering of data into the computer.
Data integrity: The need to keep the data from being corrupted by input or by deliberate attempts to tamper with the data.
Data validation: Checking the validity of data.
Data verification: Checking the correctness of data.
Database: Collection of data in a computer system ; it normally has two or more files (tables) that can interact with each other so that the need for duplication will be reduced
Debugging: Finding and correcting errors (bugs) in a program.
Decimal system: The numbering system that is based to 10
Desktop publishing: Software that can import text and graphics to the computer and can then be used to arrange them on page.
Difference engine: A machine developed by Charles Babbage in 1882 to compute logarithm tables.
Digital computer: The type of computer that operates on binary digits and relies on counting for its operations.
Direct access file: A type of storage file in which data can be accessed without the need for sequential search.
Directory: A system file that list the names and locations of all other files on a disk.
Diskette: A storage device that is flat and rectangular in shape, it is an external storage device
Disk Operating System (DOS): DOS tells the computer how to format, read and write information.
Dot matrix printer: An impact printer that create characters using a grid of pins that press against a carbon ribbon to print on paper.

E
EBCDIC: Acronym for Extended Binary Coded Decimal Interchange Code [pronounced eb-c-dick]. The standard 8-bit computer code for most IBM and IBM-compatible mainframe computers.
Editing: Altering, deleting, replacing, moving,or copying data already entered in a document.
EEPROM: An acronym for Electronic Erasable Programmable Read-Only Memory. A ROM chip that allows program information to be changed by software without removing the chips from the computer.
Electronic computers: These are computers based on binary number system.
Electronic signatures: means of ensuring that the person who sends an electronic communication is the real person that suppose to do it. It is also known as digital signatures.
Embedded system: A computer system that is built into a machine, usually to provide a means of control.
Encryption: As in data encryption.
EPROM: An acronym for Erasable Programmable Read-Only Memory. A ROM chip that must be removed from the computer for re-programming and requires the use of a special process to erase old programs.
Expert system: A computer system that stores facts about a particular topic and can search those facts for information according to a set of rules.

F
Field: An individual data item within a record.
Fifth generation computers: Computers developed from 1990 to the present. These are knowledge-based system; they endow computers with the ability to make decision in various circumstances.
File: A collection of related records.
File directory: An index that allows fast access to the files stored on a computer system
Firewall: A stand alone machine through which external messages must pass before being allowed onto a network to prevent viruses and unauthorised access doing ant damage to the system
Firmware: Another name for ROM chips that contain built-in programming functions.
Fixed disk: See a hard disk.
Fixed-length record: A record with fields that are always the same size.
Floppy disk or diskette: A small flexible disk, coated with iron oxide, on which data is stored.
Form: A layout that indicates both the items of data and where they are to be placed. It helps in the process of collecting and storing data.
Format: To prepare a blank disk so that it can be used to store information.

G
Gates: These are electronic switches that control the flow of pulses so that logic operations are carried out.
Gigabyte: Approximately 1 billion byte.
GIGO: This stands for Garbage In Garbage Out; which means what you put into the computer to process will determine your output.
Graphic- Pictorial or other data than cannot be stored in the same way as text and numbers.
Graphical User Interface (GUI): an interface that uses windows to create a border to the
Information, icons to represent files, menus to allow user to make choice and a pointer to
Select choice; hence, sometimes called a WIMP.
Graphics tablet- an input device that allows the user to input a graphic by drawing on paper
placed on the surface of the tablet.
Graphing and charting package: A program used for presenting business Graphics; its artwork can be output as transparencies or as black- and white, or color graphs on paper.

H
Hacking: The unauthorised access to computer systems. Those perform this act are called Hackers.
Handshaking- a process that take place when a computer is about to communicate with a device to establish rules for the communication.
Hard copy: Output on paper from computer.
Hard disk: A microcomputer storage device that can typically store between 10 and 100 or more million characters.
Hardware: The set devices of the computer system that can be physically seen.
High- level language- a computer programming Language that consists of statement that are similar to instruction writing in English, which makes it easier for programmers but means it has to be translate for use by the computer e.g. Pascal, Java, Basic etc.
Human / Computer Interface (HCI): The hardware and software that allows communication between a person and computer.
Hybrid: Combines the property of both digital and analogue devices.
I
Icon- a pictorial symbol on computer screen that represents a choice of activity
Indexed file: A method of database organization that uses an index based on the key field of the record. The most common method of organization for storing records on disks.
Information- data stored in the computer after it has been given a meaning by being written in context.
Ink-jet printer: A types of non-impact printer based on shooting tiny dots of ink onto paper.
Input – data that is put into a computer system or the process of putting data into a system
Instruction Register: A temporary storage location within the CPU.
Instruction set- the complete set of instructions that are used by a particular type of central processing unit
Integrated software- pieces of software that can communicate with one another and share data without changing its Form.
Integrity of data – the correctness of data during and after processing .
Integrated circuit: A circuit consisting of hundreds of electronic components, thousands of which are imprinted onto a silicon microchip.
Interpreter: A translator program that converts programs in a high-level language into machine language one statement at a time as the program is being run on the computer.
Interface – the hardware and software data create the connection between the user and the computer or the software being used
Internet- a wide area network whose contents are not controlled that is available to anyone whit a computer and modem or other way of connecting to the network
Interpreter- translator software that translates a single instruction in a high – level language, and allows it to be run before translating the next instruction
Interrupt- a signal send to the processor from some external devices, asking the processor to stop what it is doing and do something for the external device instead
Intranet – a privately operated wide area network, like the Internet except that the data content and access to it are controlled
Item- a piece of information that is stored in a field.
Iteration- the process of repeating a sequence of steps.

J
Jacquard Loom: Machine which processed information and was used by a French cloth manufacturer called Joseph Jacquard.
Jacquard, Joseph: A Frenchman who use punch cards to alter weaving loom settings without human intervention.

K
Key field: A major field on which records can be indexed in some logical order for fast access.
Keyboard: A device that Resembles typewriter keyboard: is the most common unit for entering data and for coding or using program instructions.
Kilobyte (K or KB): A measure of storage equal to 1, 024 bytes (or characters).

L
Large-scale Integration (LSI): The process of packing thousand of electronic circuits onto a single silicon chip.
Laser Printer: A types of non-impact printer that uses laser technology to produce very high-quality characters by beaming whole pages at a time onto a drum and the image is picked up with toner, like that used in xerographic copy.
Leibnitz, Gottfried von: A German mathematician, who develops a device that added, subtracted, multiplied, divided and calculated square roots. This is called stepped Reckoner.
L.E.O: One of the first computers to be built outside the university. It was built for a tea company called J.M. Lyons.
Light pen- an input device used to input data through a monitor screen
Line Number: Number at the beginning of a line, usually in BASIC, that is used to show the order in which program lines are stored in main memory.
Local area network (LAN) - networks in which the computers are physically close together and are connected by wires (or sometimes using wireless communication)
Logic data field: Fields in a record that allow only Yes/No or True /False responses.
Logic diagrams: These are representation of gates by symbols.
Logo: An educational, problem-oriented programming language that is easy for children to learn yet is powerful enough to be used for complicated programming tasks.
Loop: A program logic pattern in which the computer repeatedly executes a series of instruction a long as specified conditions are met.
Lovelace, Ada (Lady): She showed how to use the “Analytical Engine’ and she is often regarded as the first computer programmer.
Low- level language- computer programming language that consists of binary code, which is easy for the computer to understand but difficult for programmers.

M
Machine Language: A complex language that uses actual machine addresses and operation codes in order to execute a program, all programs must be in machine language in order to be executed.
Macro-a small program used to customizes a piece of software.
Main memory: The computer’s primary storage, commonly called random access memory (RAM).
Magnetic disk – storage medium that can store large amounts of data in a way that allows direct access to the data.
Magnetic ink – special ink used to print characters so that they can real by people and computer s
Magnetic ink character recognition (MICR) – the recognition by a computer of special stylized characters printed in magnetic ink
Magnetic stripe – a stripe of magnetic material that stores information about the holder, e.g. . on a credit card
Magnetic tape – storage medium that is now a bit out of data but is still used to keep back-up files on some system.
Mainframe computer – large- scale computer typically used in a large organization to provide the processing power for all the terminals in a multi- user system
Master file: The main collection of records relating to specification area.
Megabyte (MB): Approximately 1 million bytes.
Menu: A list of choice displayed on the screen from which required operations can be selected.
Microcomputer – typically a personal computer
Microfilm: Miniaturised photographic copies of document s that takes up little very storage space.
Microphone - device used to input sound to a computer system
Microprocessor – a dedicate device that incorporates all the parts of a processor on a single chip
Minicomputer- a computer that is large than a micro but smaller than a mainframe; typically used to control the checkouts in a supermarket
Modem- the hardware device that connects a computer to the telephone network and transform the computer’s digital signals to analogue and the telephone network’s analogue signals to digital; the word is an abbreviation of the modulation/demodulator’
Module- the smaller components that remain after a problem has been broken down by the use of top-down design
Monitor- a device that shows the output from a system in picture form; output is short –lived, unlike that from a printer
Multi-access OS-an operating system that allow one computer that does processing to be used by a number of people at different terminals
Multimedia package –a set of software that uses many different media to convey information, e.g. sound, graphics, animal
Multitasking OS – an operating system that allows the user to imagine that they are using the computer to do a number of different things at the same time; Microsoft Windows is a typical multitasking OS
Musical instrument digital interface (MIDI0)- a device that provides a communications link between an electronic instrument and a computer so that the sounds can be stored digitally



N
Network ¬–a group of computers that are linked together so they can communicate with one another
Network OS - an operating system that allows a number of machines to be in communication with each other and to share data. Egg Novell.
Note gate: The NOT gate will always outputs its opposite.
Number bases: The system of counting numbers, it could be binary, octal decimal, etc.
Numeric data field: A field in a record that has only numbers in it.
Numeric keypad: A section of a keyboard containing numbers, used to facilitate numeric data entry.

O
Object code-the machine code program that has been produced by translating a high-level program or an assembly language program.
Objectives of a solution- the list of things that a solution should do that has been agreed between the analyst and the user and will be used during the testing of the solution works
Offline OS-a way of using the computer in which the user or device is not directly connected to the processor
Operating system software – the set of software that controls the hardware of the computer and provides an interface with the outside world
Optical disk – a storage device that stores large amounts of data in a way that can be accessed directly using lasers, rather than magnetically
Optical mark reader (OMR)- an input device used to detect marks made in pencil on preprinted forms on documents.

Output-the result produced by a computer system after processing the input data or the action of reading information from a computer system .

P
Password - a code know only by the user that allows the computer to be sure of the identity of the person who is accessing information
Peripheral device- any device that can be connected to a computer to perform a useful task, e.g. a keyboard and a printer
Physical data- data that exists in the physical world, such as length, area, weight, this data is analogue and is not in the right from for a computer
Pixel - the smallest part of a computer graphic image; the pixel is so small that it cannot be seen
Pointing device – a device used to input to the computer by pointing at a particular output on the screen, e.g. a mouse
Point-of sale terminal - a shop till (checkout ) connected to the shop’s computer system
Polling- the process by which a processor in charge of a number of devices keeps in touch with them all by asking each in turn if they have anything new to report
Presentation software – software that allows a presentation to be produced using linked screens (or frames ) that can be followed in an order; the software will allow the use of animation and sound as well as standard outputs
Printer- device used to produced hard copy output from a computer, usually on paper
Privacy of data – some data is confidential and methods such as passwords and encryption need to be used to ensure that the wrong people do not see it.
Process control OS- an operating system that allows a processor to control the used of sensors and actuators in order to influence the physical world
Processing- the calculations /comparisons that are performed on input data in a computer system
Procedure; Description of how to perform a certain activity. It is used in LOGO and much other programming language.
Process: The stage in which input must undergo to provide output.
Processor: The part of the system that transforms input data into useful information.
Program: A set of instruction for processing data.
Programmer: A computer professional who writes programs, or sets of instruction for each application, debugs, and then documents them.
PROM: An Acronym for programmable Read-Only Memory. A ROM chip that must be removed from the computer for programming and requires the use of a special process to erase old programs.
Pulse trains: These transmit data and instructions between the various parts of the processor or between the processor, memory, and peripherals.


R
Random- access memory (RAM) – the part of the computer’s memory that is not erased when the power is turned off
Real-time OS- an operating system that processes an input and produces output quickly enough to affect the next input
Record – a of a file that store data about a particular entity; all records in the file stores the same type of data
Refreshing ¬: The processing of placing the picture on a monitor so that it is always available and up to date.
Register: A specialized storage area where the CPU holds data while performing operations on it.
Requirements specification – a list of the necessary hardware and software to put a solution into practice and a list of the wishes of the proposed user of the solution.
Re-skilling- learning and using a new skill to replace another skill that is no longer needed
Resolution- a measurement of the clarity of an image based on the number of pixel used to create the image.
S
Second-generation computers: Computers developed in the period 1955-1964; they used transistors, they were smaller, faster, and had larger. Storage capacity than first-generation computers; they were the first computers to use English-like programming language.
Scanner- a device that; allows an image that already exists to be input to the computer so that it can be manipulated using special software
Search engine- a programme used to help find information on the Internet.
Security of data- the way data is looked after to make sure that it is not damaged, lost or destroyed, typically by making back-ups of the data.
Sensor- input device that captures physical data
Sequential file- a file that stores data in a logical order, e.g. alphabetically.
Sequential medium- a storage medium, such as magnetic tapes, the store items one of after the other some sort of order.
Serial file – a file that store data in the order in which it was received.

Smart terminal- a workstation connected to a central processor as part of a multi-access computer system that can do some of its own processing.
Software- the instruction that make a computer do something useful.
Source code- the original assembly language program or high-level language program before it is translated into machine code
Speaker- a device used to produce sound output from a computer also called loudspeaker.
Spelling checker: A word processing feature that enables user to compare each word in a document with an electronic dictionary to catch errors.
Spreadsheet Package: A types of application that computerizes the record keeping function of spreadsheet ledgers or any worksheet that can be divided into rows and columns.
Status line: The line at the lower right corner of the screen when using Windows application.
Storage – somewhere to store things so that they are not when a computer system is switched off, e.g. The computer’s hard disk.
Structure Diagram – a diagram used to show how a problem can be broken down into smaller units that can be considered as separate problems, as in top-down design.
Subdirectory an index of this of a particular type
Supercomputer – the most powerful types of computer whose extremely fast processing speeds make it useful for application requiring large amounts of calculates, such weather
Syntax: The rules guiding the use of a command.
Syntax: error: An error that Occurs when the programmer violets the grammatical rules of the programming language.
System flowchart – a diagrammatic representation of the way the hardware and software operate in a system and the way that the files are stored
System Analysis –Standardized sets of steps that can be used to analyses a problem and design and implement a solution.
System analysts – the person who is responsible for carrying output the stage of system analysis on a project.
System software; Any program that control the programmer violates the grammatical rules of the programming language.


T
Technical documentation – a set of detailed descriptions about how a solution was arrived at and how it works; it is intended for someone. Who needs to develop or maintain the system?
Test plan- a set of test material designed to test specific part of a solution.
Test strategy –a decision made by the system analyst about where, when, how and by who the eventual solution is to be rested.
Third - generation computer: Computer developed in the period 1964-1971, they featured integrated circuits, reduced size, lower cost, and increased speed and reliability.
Time Dependent – a process that must be completed within a specific time.
To-down design – the braking down of a large problem into smaller problems also called stepwise refinement.
Toggle: A switch with two settings. Each time the switch is thrown, it maintains its new setting until it is thrown back again.
Touch-sensitive screen – a screen that allow input as well output; input is accomplished by touching an area of the screen
Transistor: A type of electronic circuitry that controls current flow without the use of a vacuum; it Is smaller, faster, and more reliable than vacuum tubes.
Translator: A program converting other programs from one language to another language.
Turtle: A computer controlled cybernetic animal used to draw pictures in screen in LOGO.
Type over mode: A text editing feature in which text that is currently on the screen will be overwritten by the new text you enter.
U
User documentation –a set of detailed description about how to use a system to do something useful.
User ID- a unique name or code used to let a computer system know who the user is
User: Anyone who uses the computer.


V
Validation – the checking of data input to a system to ensure that it follows certain rules and is therefore sensible.
Valve: They provide a method of switching current on and off.
Variable- a value, often in an algorithm, that can take different values at different times.
Verification – a the checking of data input to a system to ensure that it is what is meant to have been input
Video conferencing –a conference in which a number of people can all see and hear one another while they are physically separated
Video digitizer – a device that turns an analogue picture into a digital one suitable for storing in a computer
Virtual reality –an electronic environment that seems real to the user; it is achieved through the design of the input to and output from a computer system and May involved the use5 of special headgear and gloves.
Virus – a computer program that is maliciously placed on a computer system with the aim of destroying the files on that system and replicating itself so that system and replicating itself so that it can be transmitted to other systems.
Viruses’ protection – software that identifies viruses and deals with them by not allowing access or erasing them

W
Web page – information stored on a single (Scrolling) screen on the Internet as part of a website.
Website – a collection of web pages, normally on a single theme, on the Internet.
Website authoring software – software that allows the user to create a website with all the features that they want to include.
Wide area network (WAN) – a network in which the computer are so far apart that they need to be connected in some other way than simply wiring them together.
Window; A display portion of a worksheet or other document; several windows can be opened at once; Allowing you to switch between applications.
Wizard – a special feature of some software that helps user perform a specific task.
Word Processor – software designed to allow the input of text to a computer.


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