IB Computer Science (SL)

A-D converter

Analog-digital converter; "digitizer"

address bus

pathway from memory to processing unit carrying addressin in memory to and from where data is transferred

arithmetic and logic unit (ALU)

part of the CPU that performs arithmetic, logic, and similar operations

CPU

contains ALU, control unit, and registers

control unit

controls flow of data into CPU and its operation ?

registers

temporary storage location capable of holding one word

analog data

continuous data

bit

binary digit

byte

8 bits

BMP

files in bitmap form

bubble sort

...

buffer

portion of storage used to hold input or output data temporarily

bus

pathway used for sending signals between internal components of a computer; components may share same bus but can be transmitted simultaneously

cache

part of main store between main memory and processor; holds copy of data and instructions that are likely to be used next by the processor; faster than main memory

check sum

sum generated using individual digits of a number and employed as an error-detecting device

client

desktop computer or terminal used to access a computer-based system

client-server

network architecture where a system is divided between server taskes performed on instructions received from clients requesting data

compiler

translates a program into machine language, returning a list of syntax errors afterwards; produces an executable file that does not require the compiler

interpreter

tranlsates a program into machine language line-by-line, stopping if a syntax error is reached; does not produce independently executable program

data compression

method of reducing size of data; all redundancy is removed to reduce storage needed or to speed up transfer

data integrity

correctness of data after processing, storage, or transmission

data packet

part of a transmitted message that is sent separately; might include check digits, destination adress, etc

data security

method of ensuring that data is correct, safe, and cannot be read or accessed by those without permission

defragmentation software

application that reads file segments from non-contiguous sections of a storage device and writes files to same device so that each file segment is contiguous

digital data

discrete data (taken at intervals)

direct access file

file organized that a calculation provides the address of a record so the record may be directly accessed; records in file may be ordered or unordered

disk cache

RAM set aside to speed up access to a hard drive

encryption

process of transforming data into meaningless form for added security

fiber optic cables

cables used for networks made from fine strands of glass; can carry large amount of data at high speed; expensive

hub

in networking, a switch that sends data to the stations to which it is attached

LAN

computer network where all computers are directly linked via cables or microwave transmission

WAN

network providing communication services to geographic area larger than that of a LAN's; often wireless

magnetic ink character recognition

identification of characters through use of magnetic ink (OCR)

master file

permanent file holding information that can be accessessed and is periodically opdated by processing with a transaction file

transaction file

temporary file holding data that is later used for processing, generally to update a master file

mainfram

computer with extensive capabilities that may be connected to other computers to share facilities

memory address register (MAR)

holds address in memory of the instruction being executed in

modem

modulator/demodulator; converts digital signals from computer into audio to be sent over telephone lines and reconverted to digital

modulo arithmetic

arithmetic that uses integer result and integer remainder as separate components in division

modularity

aspect of programming where a program is broken into individual parts and tasks; multiple people can work on group and parts may be created and tested independently

optical character recognition (OCR)

software that reads printed characters and translates them into digital ASCII that may be used in word docs

OMR

optical mark and read forms

operating system (OS)

controls execution of programs as well as resource allocation, scheduling, peripheral management, and data management

microprocessor

integrated circuit incorporating main components of CPU; used in microcomputers and small computer-controlled devices

parity bit

binary digit appended to group of binary digits to make the sum of all digits odd or even as prescribed by predetermined protocols

peripheral device

any device that can communicate with a computer; input/ouput units, auxiliary storage, printers, keyboards, etc

pointing device

instrument such as mouse, trackball, or joystick that allows the user to move an icon onscreen

primary memory

memory where data and programs currently in use are stored

protocol

an internationally agreed set of rules meant to ensure transfer of data between devices; TCP/IP

prototyping

construction of simple version of a system during the design stage

real-time processing

manipulation of data while a process is in operation; results generally influence that process while it is occurring

router

device that identifies the destination of messages and send them via an appropriate route

secondary memory

memory allowing a user to store data and programs for unspecified period of time (eg a hard disk drive)

selection sort

...

semantics

meaning of characters/words in their syntax

sequential access

accesses records one by one in a linear fashion

server

program that provides services requested by client programs; computer that provides services to another computer over a network

star topology

network in which each device is connected to a central hub

system lifecycle

analysis, design, construction, testing, installation, maintenance

tree topology

groups of star topologies are grouped to a central cable

unicode

standardized 16-bit character set that represents character sets in most major languages; ASCII

utility

program designed to perform ordinary tastks such as copying data from one storage device to another

validation

process of checking the data input and ensuring it is the right type and within reasonable limits

virtual memory

use of secondary memory as if it were primary

virus

program that infects other programs or files by embedding a copy of itself into target files (fix with virus checker)

word

group of bits addressed, transferred, and manipulated as a single unit by CPU

binary search

list/array is divided into halves with half containing sought element again halved until it is found