Glossary Of Terms Flashcards
Adware
Adware: A piece of malware that, once installed on a computer, will show adverts or other spam to the user.
also: anti-malware
Accumulator
Accumulator (Acc): A register in the processor that stores data from calculations as they are taking place, before results are sent back to the cache or RAM
Address
Address: The location of a byte of memory. Some secondary storage devices can have multiple terabytes of memory- each byte will have an address.
AI
AI: Artificial Intelligence- the next generation of computer programs that are so advanced they seem to be capable of independent thought and reasoning. See also: Skynet
Algorithm
Algorithm: A set of step-by-step instructions for solving a problem or completing a task.
Alpha testing
Alpha-Testing: Early-stage testing of a program by it’s developers to find bugs and issues that need fixing. See also: Beta-Testing
ALU
ALU: Arithmetic & Logic unit: the part of the processor that performs calculations, comparisons and logic.
Analogue
Representing data is continuous quantity, e.g. recording a soundwave,
Analogue digital converter
I will advise the tapes, analog, signal, idiot sandwich and converts into digital recording
Anti malware
A program region, including in an operating systems, utility system software designed to protect the computer agains malware
Application layer
The first layer of the TCP/IP protocols . Contains information about the application the packet data is for.
Application software
Programs installed on a computer, such as email web, browsers or games. They rely on the operating system and system managers
Argument
A piece of data given to a subroutine to use in a place of a parameter. The subroutine must be called with the same number of arguments as parameters.
ARPANET
Precursor to the Internet built in the 1960s, it became the Internet switched over to using protocols
Array
A structure that contains many items of data often of the same type the data is indexed so that particular item can be found
ASCII
American Standard Code for Information Interchange, a
7-bit character set used by all devices for representing text
in computers. See also Extended ASCII & UNICODE
Assembler
A type of translator that converts assembly into
machine code. Often a high-level programming language’s
translator will first convert code into assembly, before
using an assembler to convert into machine code.
Assembly
A low level programming language similar in
structure to machine code, but which uses mnemonics in place
of opcodes. Assembly is converted into machine code by an
assembler.
Audio File:
A file that stores sound. The size of the file is
calculated by
Duration x Sample Frequency x Bit Depth x Channels
Authenticated
The logging in to an account with a username
and password. Note that this does not confirm someone’s
identity- it just means they know the account details.
Back-Door Access
When malware that has infected a computer
creates a connection for a hacker to access the computer’s
files and sensitive information without authorisation.
Backup
Computer files saved elsewhere in the event of a
computer failure. Backups can either be full or incremental.
Backups often occur in the cloud. Backing-up is part of the
Utility Systems Software.
Bandwidth
A measure of the speed of data transmission across
a network connection. Measured in MegabitsPerSecond (MbPS)
. Beta-Testing
Testing done by a select group of individuals
to give feedback to a program’s developers about how well it
performs.
Binary
A base-2 counting system that uses only two digits
(bits), 0 and 1. See also: Decimal & Hexadecimal
Binary Search
An algorithm that searches through a list of
data to find a search criteria. It will only work on a list
that has been sorted first, either with the bubble, insertion
or merge sort algorithm. Binary search looks at the middle
element of the list, discards the half that does not contain
the search criteria and repeats until it has been found. See
also: linear search, Bubble, Insertion, Merge sort
BIOS
Basic Input/Output System: ROM that is run on computer
start-up. It’s main purpose is to load the Operating System.
Bit
Bit (b): a binary digit; 0 or 1.
Bit Depth:
How many bits are used to encode a sound wave’s
amplitude. The higher the bit depth, the more accurately a
sample can be represented.
Black Hat Hacker:
Criminals who break into computer networks
with malicious intent, to ransom, steal or destroy files.
Range from individual amateurs to state-sponsored
professionals. See also: hacker, white hat hacke
Boolean
A data type that represents True or False values.
Boolean Operator
The operators AND, OR and NOT, that allow
condition statements to be combined into Compound Statements.
Boundary Test
When completing a Dry Run using a Trace Table,
the programmer will insert boundary data (i.e data that is on
the boundary of what the program is expecting to receive) in
order to check that the program correctly handles it. See
also: Erroneous Test, Valid Data Test
Brute Force Attack:
A method of hacking where the hacker
attempts to authenticate into an account by trying millions
of usernames and passwords, often with the use of zombie
computers. See also: hacking
Bubble Sort
An algorithm used to arrange a list of data in
order. It is the simplest to code, but the slowest to
complete for long lists due to the nested loop in its code.
See also: Insertion sort, merge sort.
Bug
An error in the program often caused by a syntax error.
IDE tools such as error diagnostics may help to debug. See
also: Logic error
BUS
A bundle of wires or tracks on a PCB carrying data from
one computer component to another. Computers have a control
bus, a data bus and an address bus.
Byte (
Byte (B): A group of 8 bits
Cache
A small amount of memory used by a computer processor
to speed up access to frequently used data. Cache memory is
often split into levels. Cache memory can be accessed faster
than RAM.
Call
To make a subroutine run, you call it.
Cell
Cell: An item of data within a database.
Casting
Casting: Converting from one data type to another.
CD
CD: Compact Disk. An optical storage device; a plastic disk
covered by metallic foil that is etched with digital data. A
laser reads the etchings as the disk rotates. Can store 700
MegaBytes of data. Cheap, durable and portable. See also: DVD
Channel
Channel: (1) A range of radio bandwidth frequencies.
Different WAPs will use different channels to avoid
interference. (2) A term used for audio files- 1 channel is
Mono, 2 channels are stereo.
Character
Character: A data type that holds a single letter, number or
symbol.
Character Set:
Character Set: A list of binary codes that represent
characters. ASCII is a character set, as is UNICODE.
Circuit switching
Circuit switching: A method of data transmission across a
network where a route from source to destination is reserved
for the duration of transmission. Used in old telephone
connections before calls were digitised and upgraded to
packet switching.
Client
Client: A device that relies on a server to connect to the
network and receive access permissions. Office computer
terminals are an example of client devices. See also: Client-
Server, Peer-to-Peer
Client-Server
Client-Server: a LAN setup where clients rely on a server to
be given access permissions to the network, access files
Clock
Clock: A vibrating quartz crystal contained within a
processor that coordinates all instruction executions by the
processor. Sometimes a processor can be overclocked.
Code
Code: A set of instructions written in a programming
language
Colour Depth
Colour Depth: The number of bits used to encode each pixel’s
RGB colour. A typical colour depth is 3 bytes
CLI
CLI: Command Line Interface: The user types in operating
system commands rather than using a GUI. A CLI gives more
access to system settings but is less intuitive to use than a
GUI.
Cloud:
Cloud: Storage located in a remote server. Useful for backing
up computer files or remote working. Users often need to pay
a monthly subscription for cloud storage.
Coding Construct:
Coding Construct: There are three coding constructs-
sequence, selection and iteration.
Comment
Comment Information typed in the program to provide
information for the programmer; it is not executed by the
program
Compound Statement:
A statement where Boolean Operators are
used to combine condition statements together,
e.g: IF age < 23 AND height >= 180
Compiler
Compiler: A program that translates source code written in a
high-level programming language into a single machine code
file that can be executed by a computer. See also: Translator
& Interpreter.
Compression
Compression: Reducing the size of a file so that it takes up
less storage. See also: Lossy Compression and Lossless
Compression
Computer
Computer: A machine that can be programmed to execute
instructions and perform tasks. A traditional Personal
Computers can often have its components upgraded, Laptops may
or may not have this ability. See also: processor, primary
memory, secondary memory, embedded system
Computer Misuse Act
Computer Misuse Act: A law designed to prosecute a hacker’s
unauthorised access to a computer network and files,
including the use of malware, ransomware, deleting or modifying files or selling data to third parties. See also:
Lawful, Data Protection Act, Copyright
Concatenation
The combining of two separate variables so
that they can be treated as one, e.g. concatenating 2 string
variables together.
Condition Statement
Condition Statement: Part of a selection instruction. By
evaluating the condition statement, the computer decides what
action to take. See also: Compound Condition Statement
Constant
Constant: A value that does not change while the program is
running.
Control Unit
Control Unit: The part of the processor that coordinates the
computer and controls the fetch-execute cycle by sending
control signals to other parts of the processor and to
peripherals through the control bus. The control unit
contains the decoder
Cooling
Removing heat from computer components, particularly
the processor. Without sufficient cooling the computer could
break. See also: Heat Sink
Copyright
Copyright: A law protecting the rights of the person or
company who created a product. See also: Lawful, Proprietary
License & Open-Source License
Core
Core: A processor may contain multiple cores- smaller
versions of itself that can perform parallel processing,
threading or multi-tasking
Correctness
Correctness: A measure of how correct a program completes a
task. See also: Efficiency
Daisy-Chain
Daisy-Chain: Connecting multiple switches together to form a
backbone for a star-topology LAN.
Database
Database: A structured and managed set of data held on a
computer. See also: Record, Table, Field, Entry, Cell
Data Center:
A facility that contains many servers; cloud-
storage servers, web-servers, game-servers etc.
Data Link Layer
Data Link Layer: The fourth layer of the TCP/IP protocols.
Adds rules for transmitting data across the network, e.g.
rules for transmission across ethernet, fibre optic or WiFi.
Data Interception and Theft:
Data Interception and Theft: An attack on a network performed
by a hacker using packet sniffing.
Data Protection Act
Data Protection Act: A law that gives right to data subjects.
Organisations must keep track of a subject’s data and record
how they use it. They must only use to for necessary
purposes. Subjects have a right to see their data and ask for
it to be deleted. See also: Lawful, Computer Misuse Act,
Copyright
Data Type:
Data Type: Different types of data include Strings,
Characters, Integers, Floats and Booleans.
DDoS Attack
DDoS Attack: Distributed Denial of Service: A hacking attack
where a website is swamped with authentication requests and
other useless traffic, in the hope of crashing the website’s
server. Good use of input sanitisation can help mitigate DDoS
attacks.
Debugging
Debugging: The process of finding and fixing errors or bugs
in a program
Decimal
A base-10 counting system with 10 digits, 0-9. See
also: Binary and Hexadecimal
Decision
When a question is asked, giving rise to two
possible outcomes. See also Selection
Decoder
a part of the control unit contained within the
processor. The decoder decodes program instructions as part
of the Fetch-Execute cycle
Decomposition
Decomposition: After abstracting a problem, the programmer
will break down the problem into smaller, manageable tasks
that are easier to program and maintain, usually with use of
subroutines.
Defensive Design
Defensive Design: Also known as robust programming: A program
coded in such a way as to be able to deal with all erroneous
data or transcription errors a user may input, without
crashing. E.g, the use of try…except code blocks in Python.
See also: Maintainability, Erroneous Test
Definite Iteration:
Definite Iteration: Iteration that repeats a known number of
times. In Python For… loops are examples of definite
iteration. See also: Indefinite Iteration
Defragmentation Software
Defragmentation Software: Part of the utility system
software. Used to rearrange data in the hard drive so files
and programs are stored in contiguous blocks, making them
faster to load into the RAM when opened. Defragmenting is
only necessary for hard drives, that have to physically
rotate their magnetic disks to data can be read by the reader
head. See also: Magnetic
Digital
Digital: Representing data in discrete form, e.g. in binary
data. Digital is the opposite of Analogue.
DNS
DNS: Domain Name Server / Domain Name Service: A server on a
WAN that stores all domain names and their associated IP
addresses. When a user enters a URL, the DNS is queried and
the IP address of the domain is returned, allowing the user’s
computer to load the website. Domain names are much easier to
remember than IP addresses.
Domain Name
Domain Name: A unique, easy to remember address used to
access a website. Domain names are much easier to remember
than a website’s IP address. See also: DNS, URL
Driver
Driver: A program which is managed by the Peripheral Manager
of an Operating System. It is used to interface with
peripheral devices such as printers, monitors and mice.
Dry Run
The program is run on paper by the programmer using
a Trace Table. Each step is analysed to track the inputs and
outputs to check for Logic Errors in the code. See also
Erroneous Test, Boundary Test
DVD
an upgraded version of a CD. Can hold up-to 30 GigaBytes
of data. See also: optical
Dynamic Array
Dynamic Array: An array that has not had its size defined and
can be resized as data is appended.
Efficiency
Efficiency: A measure of how quickly a program completes a
task. See also: Correctness
Element
Element: An item in a list. Can be any data type. List
elements are indexed.
Embedded System
Embedded System: a computer embedded within a larger device,
designed as cheaply as possible to perform a specific task.
It’s hardware cannot be upgraded.
Encryption:
Encryption: The process of converting plain data into
scrambled data to protect sensitive information from
unauthorised access. Encryption software is part of the
utility system software. See also: packet sniffing
Entry
Entry: A record of data within a database- usually a row of a
table, e.g. the entry of a person in a census database.
Erroneous Test:
Erroneous Test: When completing a Dry Run using a Trace
Table, the programmer will insert erroneous data (i.e data
that the program is not expecting to receive) in order to
check that the program correctly handles it. See also:
Boundary Test, Valid Data Test
Ethernet
Ethernet: An electrical cable used to transmit data. Also a
protocol for transmitting data, part of the Data Link Layer
of the TCP/IP protocol set of rules. See also: Fibre Optic,
Microwave
Ethics
Ethics: A system of moral principles that society recognises
as being right and good values.
Execute:
Execute: To run a program or script.
Extended ASCII
Extended ASCII: An upgraded version of the ASCII character
set that stores more character codes because it uses 8 bits.
Fetch-Execute Cycle
Fetch-Execute Cycle: The cycle of operations performed by a
computers processor to execute program code. First the next
instruction is fetched from cache or RAM. Next the
instruction is decoded and the processor decides what to do
with it. Lastly the instruction is executed.
Fibre optic:
Fibre optic: A method of data transmission used in
networking. Uses thin strands of glass to transmit digital
optical pulses of light. Thanks to multiplexing, Fibre optic
can transmit huge bandwidths of data. Used in both LANs and
WANs, particularly in trans-oceanic cables.
Field
Field: One item of information, e.g. the make of a car.
Fields are often the rows or columns in a database.
File:
File: A container of information in digital format, often
stored in secondary storage. Useful for storing data
generated by running programs. Files are managed by the file
manager. See also: Image File, Sound File, Text File, Lossy
Compression, Lossless compression
File Manager:
File Manager: One of the four managers contained within the
operating system. Manages data storage in the computer.
Creates, names and saves files. Arranges files in folders and
directories. Works with the user and permissions manager to
control user access to files.
Firewall
Firewall: A piece of hardware or utility system software that
monitors and controls incoming and outgoing network traffic
to prevent unauthorised access. See also: malware
Flash Memory
Flash Memory: Non-volatile solid-state secondary storage,
also called a data-stick, thumb-drive, USB-stick etc. Small,
cheap and portable.
Float
Float: A data type that contains decimal numbers. An integer
could be stored in a float variable, but a float could not be
stored in an integer variable.
Floppy Disk
Floppy Disk: A low-capacity secondary storage device, first
produced in 1971 but obsolete by the 1990’s. Could store 1.44
MegaBytes of data
Footer:
Footer: Information added to the end of a data packet before
it is transmitted across a network. Footers contain error-
checking codes and an ‘end of packet’ signal. See also:
header
Frequency
Frequency: The number of times per second- used when
describing radio waves or the number of audio wave samples
taken per second. See also: Channels, Audio files
FTP
FTP: File Transfer Protocol: One of the application layer
protocols from the TCP/IP protocols, used when transferring
files across a network
Function
Function: A subroutine where data is returned to the
variable(s) that called it. The function must be called by
the same number of variables as the pieces of data it
returns. Functions can use parameters. See also: procedure