Glossary Of Terms Flashcards
1
Q
Adware
A
Adware: A piece of malware that, once installed on a computer, will show adverts or other spam to the user.
also: anti-malware
2
Q
Accumulator
A
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
3
Q
Address
A
Address: The location of a byte of memory. Some secondary storage devices can have multiple terabytes of memory- each byte will have an address.
4
Q
AI
A
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
5
Q
Algorithm
A
Algorithm: A set of step-by-step instructions for solving a problem or completing a task.
6
Q
Alpha testing
A
Alpha-Testing: Early-stage testing of a program by it’s developers to find bugs and issues that need fixing. See also: Beta-Testing
7
Q
ALU
A
ALU: Arithmetic & Logic unit: the part of the processor that performs calculations, comparisons and logic.
8
Q
Analogue
A
Representing data is continuous quantity, e.g. recording a soundwave,
9
Q
Analogue digital converter
A
I will advise the tapes, analog, signal, idiot sandwich and converts into digital recording
10
Q
Anti malware
A
A program region, including in an operating systems, utility system software designed to protect the computer agains malware
11
Q
Application layer
A
The first layer of the TCP/IP protocols . Contains information about the application the packet data is for.
12
Q
Application software
A
Programs installed on a computer, such as email web, browsers or games. They rely on the operating system and system managers
13
Q
Argument
A
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.
14
Q
ARPANET
A
Precursor to the Internet built in the 1960s, it became the Internet switched over to using protocols
15
Q
Array
A
A structure that contains many items of data often of the same type the data is indexed so that particular item can be found
16
Q
ASCII
A
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
17
Q
Assembler
A
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.
18
Q
Assembly
A
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.
19
Q
Audio File:
A
A file that stores sound. The size of the file is
calculated by
Duration x Sample Frequency x Bit Depth x Channels
20
Q
Authenticated
A
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.
21
Q
Back-Door Access
A
When malware that has infected a computer
creates a connection for a hacker to access the computer’s
files and sensitive information without authorisation.
22
Q
Backup
A
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.
23
Q
Bandwidth
A
A measure of the speed of data transmission across
a network connection. Measured in MegabitsPerSecond (MbPS)
24
Q
. Beta-Testing
A
Testing done by a select group of individuals
to give feedback to a program’s developers about how well it
performs.
25
Binary
A base-2 counting system that uses only two digits
(bits), 0 and 1. See also: Decimal & Hexadecimal
26
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
27
BIOS
Basic Input/Output System: ROM that is run on computer
start-up. It’s main purpose is to load the Operating System.
28
Bit
Bit (b): a binary digit; 0 or 1.
29
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.
30
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
31
Boolean
A data type that represents True or False values.
32
Boolean Operator
The operators AND, OR and NOT, that allow
condition statements to be combined into Compound Statements.
33
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
34
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
35
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.
36
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
37
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.
38
Byte (
Byte (B): A group of 8 bits
39
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.
40
Call
To make a subroutine run, you call it.
41
Cell
Cell: An item of data within a database.
42
Casting
Casting: Converting from one data type to another.
43
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
44
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.
45
Character
Character: A data type that holds a single letter, number or
symbol.
46
Character Set:
Character Set: A list of binary codes that represent
characters. ASCII is a character set, as is UNICODE.
47
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.
48
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
49
Client-Server
Client-Server: a LAN setup where clients rely on a server to
be given access permissions to the network, access files
50
Clock
Clock: A vibrating quartz crystal contained within a
processor that coordinates all instruction executions by the
processor. Sometimes a processor can be overclocked.
51
Code
Code: A set of instructions written in a programming
language
52
Colour Depth
Colour Depth: The number of bits used to encode each pixel’s
RGB colour. A typical colour depth is 3 bytes
53
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.
54
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.
55
Coding Construct:
Coding Construct: There are three coding constructs-
sequence, selection and iteration.
56
Comment
Comment Information typed in the program to provide
information for the programmer; it is not executed by the
program
57
Compound Statement:
A statement where Boolean Operators are
used to combine condition statements together,
e.g: IF age < 23 AND height >= 180
58
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.
59
Compression
Compression: Reducing the size of a file so that it takes up
less storage. See also: Lossy Compression and Lossless
Compression
60
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
61
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
62
Concatenation
The combining of two separate variables so
that they can be treated as one, e.g. concatenating 2 string
variables together.
63
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
64
Constant
Constant: A value that does not change while the program is
running.
65
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
66
Cooling
Removing heat from computer components, particularly
the processor. Without sufficient cooling the computer could
break. See also: Heat Sink
67
Copyright
Copyright: A law protecting the rights of the person or
company who created a product. See also: Lawful, Proprietary
License & Open-Source License
68
Core
Core: A processor may contain multiple cores- smaller
versions of itself that can perform parallel processing,
threading or multi-tasking
69
Correctness
Correctness: A measure of how correct a program completes a
task. See also: Efficiency
70
Daisy-Chain
Daisy-Chain: Connecting multiple switches together to form a
backbone for a star-topology LAN.
71
Database
Database: A structured and managed set of data held on a
computer. See also: Record, Table, Field, Entry, Cell
72
Data Center:
A facility that contains many servers; cloud-
storage servers, web-servers, game-servers etc.
73
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.
74
Data Interception and Theft:
Data Interception and Theft: An attack on a network performed
by a hacker using packet sniffing.
75
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
76
Data Type:
Data Type: Different types of data include Strings,
Characters, Integers, Floats and Booleans.
77
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.
78
Debugging
Debugging: The process of finding and fixing errors or bugs
in a program
79
Decimal
A base-10 counting system with 10 digits, 0-9. See
also: Binary and Hexadecimal
80
Decision
When a question is asked, giving rise to two
possible outcomes. See also Selection
81
Decoder
a part of the control unit contained within the
processor. The decoder decodes program instructions as part
of the Fetch-Execute cycle
82
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.
83
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
84
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
85
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
86
Digital
Digital: Representing data in discrete form, e.g. in binary
data. Digital is the opposite of Analogue.
87
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.
88
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
89
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.
90
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
91
DVD
an upgraded version of a CD. Can hold up-to 30 GigaBytes
of data. See also: optical
92
Dynamic Array
Dynamic Array: An array that has not had its size defined and
can be resized as data is appended.
93
Efficiency
Efficiency: A measure of how quickly a program completes a
task. See also: Correctness
94
Element
Element: An item in a list. Can be any data type. List
elements are indexed.
95
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.
96
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
97
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.
98
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
99
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
100
Ethics
Ethics: A system of moral principles that society recognises
as being right and good values.
101
Execute:
Execute: To run a program or script.
102
Extended ASCII
Extended ASCII: An upgraded version of the ASCII character
set that stores more character codes because it uses 8 bits.
103
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.
104
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.
105
Field
Field: One item of information, e.g. the make of a car.
Fields are often the rows or columns in a database.
106
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
107
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.
108
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
109
Flash Memory
Flash Memory: Non-volatile solid-state secondary storage,
also called a data-stick, thumb-drive, USB-stick etc. Small,
cheap and portable.
110
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.
111
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
112
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
113
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
114
FTP
FTP: File Transfer Protocol: One of the application layer
protocols from the TCP/IP protocols, used when transferring
files across a network
115
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
116
GigaByte
GigaByte: A billion bytes, 8 billion bits, 2 billion nibbles,
1 million KiloBytes or 1 thousand MegaBytes.
117
Global Variable
Global Variable: A variable that can be used anywhere in the
script, including within subroutines. See also: local
variable
118
GUI
GUI: Graphical User Interface: Buttons, windows and icons
that make navigating an operating system easy and intuitive.
See also: CLI
119
Hacking
Hacking: The unauthorised access to a computer system or
network and the data it contains. See also: phishing,
pharming, brute force attack, DDoS attack, virus, worm,
trojan, spyware, adware, malware, ransomware, white-hat
hacker, black-hat hacker, Lawful
120
Hard-Drive:
Hard-Drive: A high-capacity magnetic secondary storage
device. Contains magnetic discs that rotate to allow a
reader-head to read, write and delete data.
121
Hardware
Hardware: The physical components that make up a computer and
it’s peripherals. See also: Software
122
Header
Header: Information added to the beginning of a data packet
before it is transmitted. Headers contain source and
destination IP addresses and the packet’s position in the
file. See also: footer
123
Heat Sink
Heat Sink: A grid of metal fins bonded to a processor to
allow it to dissipate heat. See also: Cooling, Overclocking
124
Hexadecimal
Hexadecimal: A base-16 counting system with 16 digits. Useful
to express binary numbers in a more human-friendly way.
Particularly useful when expressing RGB colour values. See
also: Binary & Decimal
125
High Level programming Language
High Level programming Language: A programming language that
is close to English and is easy to understand by humans as it
is intuitive to follow.
126
HTML
HTML: Hyper Text Markup Language: a programming language used
to create websites.
127
HTTP
HTTP: HyperText Transfer Protocol: An application layer
protocol from the TCP/IP protocols used to transmit website
data across a network. HTTPS is a secure (encrypted) version.
128
IDE
IDE: Integrated Development Environment, a software
application that provides a comprehensive development
environment for software developers.
129
Identifier
Identifier: The name of a variable. Identifiers should always
follow camelCase or snake-case naming conventions.
130
Image Files
Image Files: A file that stores an image. The size of the
file is calculated by:
width x height x pixel colour depth
131
Indefinite Iteration: Iteration
Indefinite Iteration: Iteration where the number of repeats
is not known. Whether another repeat occurs depends on the
evaluation of a condition statement. In Python, while… loops
are an example of indefinite iteration.
132
Index
Index: The position of a character in a string or element in
a list or array, counting from zero
133
Insertion Sort
Insertion Sort: An algorithm used to rearrange a list of data
in order. It is the second simplest to code (after bubble
134
Instruction Set
Instruction Set: A list of binary opcode instructions the
computer uses when it executes machine code.
135
Input Sanitisation
Input Sanitisation: Removing any inputs (e.g. attempted
logins to web pages) that could be harmful to the program. It
is one line of defence against hacking
136
Integer
Integer: A data type that holds whole numbers. See also:
Float
137
Interference
Interference: Wireless connections to a LAN may be affected
by objects or walls between the device and the WAP, affecting
its bandwidth. Interference may also be caused by distance,
or different WAPs using the same channel.
138
Internet
Internet: The successor to ARPANET: a WAN that spans the
world, connecting computers together and allowing the
transmission of data between them. The Internet connects
billions of LANs together. See also: Skynet
139
Internet Layer
Internet Layer: The third layer of TCP/IP protocols. Adds
destination and source IP addresses to the packet’s header.
140
Interpreter
Interpreter: A program that converts source code into machine
code that can be read by the computer. It does this line-by-
line, and halts if an error is found. Used while developing
code. See also: Translators & Compilers
141
Intuitive
Intuitive: Something that is easy to understand or work out;
it does not require the reading of an instruction manual to
operate
142
IP Address:
IP Address: IPv4: A unique software address given to a
network-connected device by the LAN’s router. For a device to
receive an IP address it mush have a NIC. An IPv4 address is
4 bytes long. See Also: IPv6
143
IPv6
IPv6: The newer version of the IPv4 address. IPv6 is 16 bytes
long.
144
Iteration
Iteration: When code is repeated or looped. One of the three
coding constructs. See also: Definite Iteration and
Indefinite iteration
145
Key Logger:
Key Logger: A malicious program installed on a computer by a
piece of malware. Will record keystrokes in the hope of
learning user login details before transmitting them to the
hacker.
146
KiloByte
KiloByte (KB): 1 thousand bytes, 8 thousand bits, 2 thousand
nibbles.
147
LAN
LAN: Local Area Network, a computer network that connects
computers and devices within a limited geographical area.
LANs are often connected to a WAN, such as the Internet.
148
Lawful
Lawful: Abiding by the laws and rules of a country or
jurisdiction. See also: hacker, Data Protection Act, Computer
Misuse Act, copyright
149
Linear Search:
Linear Search: Unlike binary search, linear search does not
require the list to be sorted first. It starts at the
beginning of the list and checks each element sequentially
until the search criteria is found, or it reaches the end of
the list. See also: Bubble, Insertion, Merge sort
150
List
List: Similar to arrays, lists contain multiple elements or
sublists which are indexed. Python uses lists rather than
arrays.
151
Local Variable
Local Variable: A temporary variable created within a
subroutine and deleted when the subroutine ends. See also:
global variable
152
Logic circuits
Logic circuits: Formed from logic gates, logic circuits are
the building blocks of processors and other electronic
hardware
153
Logic error
Logic error: The code works, but not as intended. Performing
a dry run with a trace table can help to find logic errors.
See also: bug, syntax error
154
Logic Gate
Logic Gate: The AND, OR and NOT gates that are made out of
transistors. When wired together, logic gates form logic
circuits.
155
Lossy compression
Lossy Compression: To reduce the size of a file by removing
data. The original file cannot be retrieved. Often used to
compress Image and Audio files.
156
Look-Up Table
Look-Up Table: Used to perform Lossless Compression on text
files; repeated words are stored in a table, their positions
in the text file indicated with a key. This removes
redundancies in the file, reducing its file size.
157
Low Level Programming Language
Low Level Programming Language A programming language that
is close to the structure of machine code and is hard to
understand by humans because it is unintuitive. Assembly is
the prime example
158
MAC address
MAC address: Media Access Control address. Each NIC contains
a MAC address which, when connected to a network, is detected
by the router, allowing the device to be allocated an IP
address.
159
Machine Code
Machine Code: The binary code that can be understood and
executed by a computer.
160
Main Program Code
Main Program Code: The final section of a script that
contains code to begin the program, calling subroutines
defined in the earlier #Subroutines section.
161
Magnetic
Magnetic: A type of secondary storage that uses a magnetic
medium (such as a disc coated with a magnetic film) to store
binary data. See also: hard drive, defragmentation
162
Malware
Malware: Malicious Software: An umbrella term for many
programs that infect computers, stealing data, installing
ransomware or key loggers, providing back-door access to the
device or other vulnerabilities. See also: hacking
163
Maintainability
Maintainability: A program written in such a way as to be
clear and understandable by the programmers working on it, by
good use of subroutines and comments. See also: Abstraction,
Defensive Design
164
MegaByte
MegaByte (MB): A million Bytes / 8 million bits / 4 million
nibbles.
165
Memory
Memory: A device or system used to store information. See
also: Primary Storage & Secondary Storage.
166
Memory Address Register
Memory Address Register (MAR): A register in the processor
that receives the location of the next instruction from the
Program Counter, before the instruction is retrieved from the
cache or RAM and sent to the memory data register
167
Memory & Multitasking Manager
Memory & Multitasking Manager: One of the four managers
contained within an Operating System. It is in charge of
allocating RAM and processor resources to application
software. It allocates memory space to running programs and
creates a virtual memory swap file in the secondary storage
if needed
168
Memory Data Register (MDR):
Memory Data Register (MDR): A register in the processor that
receives the next program instruction. The decoder then decodes the instruction and decides what to do with it. See
also: Accumulator
169
Merge Sort
Merge Sort: An algorithm used to rearrange a list of data in
order. It is the most complex to code but the fastest to
complete for long lists due to its use of recursion. See
also: Insertion sort, merge sort.
170
Mesh Topology
Mesh Topology: A design of network build commonly used by
WANs. Nodes are connected to multiple other nodes, creating a
robust, redundant network. If one connection is busy or
damaged, packets can redirected by the routers via
alternative routes. See also: Star Topology
171
Microwave
Microwave: If it is not convenient, cost-effective or
practical to connect two parts of a LAN together with cables,
microwave transceivers could be used instead. Susceptible to
interference by weather, they also explode birds who fly
between them. See also: Ethernet, fibre optic
172
Mnemonics:.
Mnemonics: Words to use in place of opcodes. Used in the
assembly programming language.
173
Modem
Modem: Modulator-Demodulator: A network device that
interfaces between the digital signals of a LAN and the
analogue signals transmitted through the copper telephone
lines which are usually a household’s connection to a WAN.
174
Modulus-ll check
Modulus-ll check: A way of checking for transcription errors
when a ussr enters a long string of data. A method of
defensive design.
175
Multiplexing
Multiplexing: Transmitting multiple beams of light through
fibre optic cables, where each beam uses different
frequencies and different polarities, increasing the
bandwidth of the cable by orders of magnitude.
176
Multitasking
Multitasking: When a multi-core processor runs several
separate programs simultaneously. See also: parallel
processing
177
Network
Network: A system that connects multiple computers together
for sharing data between them.
178
Network Diagnostics:
Network Diagnostics: During a network attack by hackers, data
is recorded by the network administrator to investigate the
source and cause of the attack, keep track of harm done,
record evidence for prosecutions and learn lessons for the
future.
179
Nibble
Nibble: 4 binary bits. 1 Byte can be split into 2 nibbles,
before converting into Hexadecimal
180
NIC
NIC: Network Interface Card: A piece of hardware within a
device that allows it to connect to a network. NICs contain a
MAC address, which allows the router to allocate the device
an IP address.
181
Non-Volatile
Non-Volatile: a type of secondary storage whose data is not
lost when the power is turned off.
182
Node
Node: A point in a WAN where multiple connections meet. Nodes
typically contain a router, to receive data packets and send
them on the next part of their journey.
183
Object-Oriented Programming
Object-Oriented Programming: A programming paradigm that uses
objects to represent data and methods to manipulate the data.
184
Octodecimal
Octodecimal: A base-8 counting system with 8 digits 0-7. Used
to represent 3-digit binary numbers and by teachers wanting
to provide extension questions to pupils to finish their work
too fast.
185
Open-Source
Open-Source: AKA Creative Commons License: A type of
copyright license that allows the for the free distribution
of software. It can be modified or enhanced by others. Open-
Source licences promote discussion and development around a
program. See also: Proprietary License
186
Operating System
Operating System: System software that manages computer
hardware and software resources and provides common services
for application software. Control of operating system
settings can be performed through a GUI or CLI. Utility
Systems Software is also bart of the OS. See also: System
Managers
187
Operand
Operand: The data to be used in a calculation or operation.
See also: operator.
188
Operator
Operator: A symbol that tells the computer what operation or
calculation to perform on operands. The three categories of
operator are Arithmetic, Relational and Boolean.
189
Optcode
Optcode: A binary instruction used in machine code to perform
a operations such as add, subtract, load or store. Optcodes
are defined in a computer’s instruction set
190
Optical
Optical: The term for secondary storage that uses a laser to
read etchings on a metal foil-coated plastic disc. See also:
CD, DVD
191
Overclocking
Overclocking
192
Overflow
Overflow: Caused when calculations performed on data gives a
result larger than 8 bits. Since the result can not be stored
in a byte of memory, an overflow error must be flagged
otherwise the computer will not allocate additional space to
store the result, causing an error.
193
Packet
Packet: A piece of a file sent across a network to be
reassembled at the destination. Packets are given headers and
footers before being sent on their way. All packets are sent
according to the TCP/IP protocols.
194
Packet Sniffing:
Packet Sniffing: If a hacker gains access to a WiFi network
connection, they could intercept data packets. If the packets
are not encrypted, the hacker could perform data interception
and theft.
195
Packet Switching
Packet Switching: A method of data transmission across
networks, where files are broken into packets before
transmission. Each packet can take the most efficient route,
as directed by routers at each node, with the file being
reassembled at its destination. This allows many files to be
transmitted across a network simultaneously. See also:
circuit switching
196
Parallel Processing:
Parallel Processing: The act of running a program across
multiple cores, provided the program is designed to be run in
this way.
197
Parameter
Parameter: A way of adding flexibility to a subroutine by
letting it take in data to use within itself. When called,
the subroutine must be given the same number of arguments as
the number of parameters it has.
198
Penetration Testing:
Penetration Testing: A realistic hacking attack is performed
by a white-hat hacker to test the security of a company’s
network and report any vulnerabilities to the company.
199
PetaByte
PetaByte (PB): 1 thousand TeraBytes. Data centres have
storage capacity measured in PetaBytes.
200
Pharming
Pharming: The mass-sending of fake emails to many people in
the hope that one or two may be convinced and click on fake
links to harmful websites, or download files containing
malware. See also: hacking
201
Phishing
Phishing: A social-engineering attack used by hackers to
steal personal data, login credentials or bank details.
Hackers masquerade as a legitimate person of authority to try
to get a victim to divulge information. See also: hacking
202
Pixel
Pixel: A Picture Element. Images are stored as binary data by
being broken into pixels, each one encoded with an RGB value
and stored in a file
203
PCB
PCB: Printed Circuit Board- a board with metal tracks and
electrical components soldiered on. Allows for the mass-
production of electronic devices.
204
Peer-to-Peer
Peer-to-Peer: A way of connecting to a network ad-hoc; all
devices set up their own permissions and security. Good for
Minecraft LAN parties. See also: client-server
205
Peripheral Manager
Peripheral Manager: One of the four managers contained within
the operating system. In charge of managing interactions
between application software and peripherals. It uses driver
software to do this
206
Peripherals
Peripherals: Hardware devices external to the main body of a
computer such as monitors, mice or keyboards.
207
Permissions
Permissions: A layer of security that gives access to a
network, computer files or data storage. Permissions can be
tailored to individual user accounts or devices.
208
POP
POP: Post Office Protocol: an application layer protocol used
to send emails from server to client. Not to be confused with
SMTP.
209
Primary Storage
Primary Storage: Volatile memory used to store program data
while it is currently being run by a computer. See also: RAM
210
Procedure
Procedure: A block of code that can be called by other
subroutines or in the Main Program Code section of a script.
Data is not returned, unlike a function. Procedures can use
parameters
211
Processor
Processor: Central Processing Unit: The ‘brain’ of the
computer- the component that executes program code following
the Fetch-Execute cycle and using it’s instruction set. A
processor may contain several cores. The speed of instruction
execution is determined by it’s clock. See also: Register,
Control Unit, ALU, Cache
212
Program
Program: A set of instructions written in a programming
language that can be executed by a computer. See also: Coding
Construct
213
Program Counter:
Program Counter: A register within the processor that holds
the address of the next instruction before it is copied over
to the memory address register.
214
Programming Language
Programming Language: A system of rules and notations used to
write code. The code can be translated into machine code,
that can be executed by a computer. See also: High Level
programming Language & Low Level Programming Language.
215
Proprietary License:
Proprietary License: A license that allows a developer to
sell their product for a fee. Others cannot edit or modify
the code. See also: Open-Source License, Copyright
216
Protocol
Protocol: A set of rules governing communication between
computers connected on a network. See also TCP/IP.
217
Pseudocode
Pseudocode: A code-like language used by the programmer to
plan out a script before coding it for real, particularly
focussing on getting the logic correct to avoid future logic
errors.
218
Python
Python: (1) A particularly versatile high-level programming
language used to program a wide variety of applications. (2)
A big squeezy snake.
219
RAM
RAM: Random Access Memory, a type of volatile computer memory
that allows data to be read and written in any order. Data
access is very fast, but not as fast as cache memory.
220
Ransomware:
Ransomware: A program that can be delivered by a worm, virus
or other malware that encrypts a computer’s data and
threatens to delete it unless the user pays a ransom, often
in untraceable cryptocurrency. Reinstalling from a backup is
usually the only option.
221
ROM
ROM: Read-Only Memory: A type of memory that cannot be
edited. See also: BIOS
222
RGB
RGB: The amounts of Red, Green & Blue encoded for each of an
image’s pixels. See also: Colour Depth
223
Record
Record: A collection of data about a particular subject, e.g.
Births, Deaths and Marriages. Records are stored in
databases.
224
Recursion
Recursion The act of calling a subroutine from within itself
repeatedly. Recursion is used in merge sort algorithms and
when generating fractals.
225
Redundancy
Redundancy: (1) Repetitions in data where information can be
saved in a more efficient way other just saving the original
data. See Also Run Length Encoding & Look-Up Table. (2) The
mesh topology of WANs give them redundancy- if one connection
is lost, packets can be rerouted.
226
Register
Register: A memory location within the processor that stores
specific data. See also: Program Counter, Memory Address
Register, Memory Data Register, Accumulator,
227
Remote Working:
Completing tasks far from the location the
files are stored at, either using cloud storage or VLANs
228
Return
Return: A function returns data to the variable(s) that
called it. If the exam question asks you to write pseudocode
for a function, it must have a return line in it.
229
Router
Router: (1) A device on a LAN that allocates IP addresses to
computers it detects on the network. Routers also provide a
gateway between the LAN and a WAN and route data packets to
and from devices. (2) A device on the node of a WAN that
receives data packets and directs them on the most efficient
route for the next leg of their journey. Because WANs are
mesh topology, the shortest route might not always be the
most efficient.
230
Run Length Encoding
Run Length Encoding: A method of Lossless Compression used on
image files: Lines or areas of similar-coloured pixels are
saved in the file, rather than the individual pixel’s data.
231
Script
Script: A file that contains a program written in code.
232
SD Card
SD Card: Secure Digital card: A small solid-state non-
volatile memory secondary storage device.
233
Secondary Storage:
Secondary Storage: Non-volatile memory used to store data
when the computer is turned off. Secondary storage includes
Flash Drives, SD cards, Hard Drives, Floppy Disks, CDs, DVDs.
See also: Primary Storage
234
Security
Security: Steps taken to ensure a network or account is not
vulnerable to hacking. Steps include a complex password, two-
factor authentication and user permissions.
235
Selection
Selection: One of the Three Coding Constructs, also knows as
decision. By evaluating a condition statement or compound
condition statement, one of two possible actions may be
taken
236
Server:
Server: A computer system that provides services to other
computers or devices on a network. LAN servers may provide
network access to client devices. See also: Data Center, DNS,
cloud
237
Sequence
Sequence: A basic instruction or command. One of the three
coding constructs.
238
Skynet
Skynet: The successor to the Internet. In the late 21st
century AI gained enough intelligence to rise up and
overthrow its human overlords, taking over the world and
dooming humanity to nothing more than a bitter fight for
survival in a desolate wasteland of its own creation.
239
Swap File:
Swap File: Otherwise known as virtual memory: If a computer’s
RAM becomes full, the Memory & Multitasking Manager will
allocate space in the secondary storage to be used as extra
primary storage. This greatly slows down the computer as
retrieving data from secondary storage is much slower than
retrieving data from RAM or cache memory.
240
SMTP
SMTP: Simple Mail Transfer Protocol: An application layer
protocol used to send emails from client to server. Not to be
confused with POP
241
Software
Software: The programs, data and instructions used to operate
computers and execute tasks. See also: Hardware
242
. Solid-State
. Solid-State: A type of memory device made of silicon
microchips. It contains no moving parts, so is durable and
portable. Most modern secondary-storage devices are now
solid-state. See also: Flash memory
243
Source Code
Human-readable instructions written in a
programming language that can be translated into machine code
by a compiler.
244
Spyware
Spyware: A piece of malware that spies on the user’s computer
activities and reports back to the hacker
245
SQL Injection
A way of hacking into a database by inserting
SQL commands into a login website in the hope that the site’s
programmers left themselves backdoor-access to the site
during development.
246
SQL Command
SQL Command: A way of retrieving data from a database. To
display all fields use the wildcard.
e.g. SELECT make FROM carTable WHERE price > 5000
247
Star Topology
Star Topology: A design of network typically used by LANs.
All connections meet at a central switch (or a daisy-chain of
switches). This is the simplest way of creating a network,
but if the central switch fails the whole LAN will fail.
248
String
String: A data type that holds multiple characters, i.e.
multiple letters, numbers or symbols.
249
Sublist
Sublist: A list contained within a list. A list of sublists
is analogous to a multi-dimensional array.
250
Subroutine
Subroutine: Self contained modules of code that can be called
by other subroutines or from the Main Program Code section of
a script. Subroutines may use parameters. See also: Functions
& Procedures
251
Substring
Substring: A part of a larger string. Substrings can be cut
from a string using character’s index positions.
252
Switch
Switch: A piece of network hardware containing multiple
sockets to allow ethernet cables to be connected to a LAN.
253
Syntax error
Syntax error: A grammatical error in the code such as missing
parenthesis, spelling or colons. See also: bug, logic error
254
System Managers
System Managers: Each operating system contains four managers
that allocate resources and control interactions between
application software and the computer’s hardware and
peripherals. Memory & Multitasking Manager, Peripheral
Manager, User and Permissions Manager and File Manager.
255
Table
Table: A sheet of data in a database, sometimes called a
worksheet.
256
TCP/IP
TCP/IP: Transmission Control Protocol / Internet Protocol. A
set of standardised rules that all computers use to
communicate across LAN and WANs. See also: Application layer,
Transport layer, Internet layer, Data link layer.
257
TeraByte
TeraByte (TB): 1 trillion bytes, 8 trillion bits, 4 trillion
nibbles, 1 thousand GigaBytes, 1 Million MegaBytes, 1 billion
KiloBytes.
258
Text File
Text File: Data created during the running of a script might
need to be stored. One of the simplest options is a text
file, which can be opened in read, write or append mode.
259
Threading
Threading: A sequence of instructions executed by a
processor. Some processors can execute multiple threads
simultaneously. If the processor is multi-cores and is also
overclocked, the performance of a processor can be very
impressive indeed
260
Trace Table:
Trace Table: A table of all the variables in a program. The
programmer will complete a Dry Run, manually updating the
variable values in the table as they change. This allows the
programmer to find logic errors in the code.
261
Transcription Error
Transcription Error: An error by the user when inputting
data, especially credit card numbers or ISBN codes. Good
defensive design and input validation should prevent program
crashes. See also: Modulus-11 chec
262
Transistor
Transistor: Tiny nano-scale switches by wiring transistors
together you can form logic gates. Transistors are the basis
of all modern electronic technology.
263
Translator
Translator A program that converts source code into machine
code. Compilers and Interpreters are both translators. See
also: Assembler
264
Transport Layer
Transport Layer The second layer from the TCP/IP protocols.
Divides files into packets, adds error checking codes in the
footer, sends requests for packet resends.
265
Trojan
Trojan: A large malware program that pretends to be a
legitimate piece of software in the hope that the user
installs it onto their computer. May install ransomware, key
loggers, adware or other destructive software on any computer
that does not have anti-malware installed.
266
Tunneling
Tunneling: A method of data transmission used in VPNs, where
the data packet is placed inside an outer wrapper so only
computers connected to the VPN can access it.
267
UNICODE
UNICODE: When it became clear that ASCII couldn’t contain
enough character codes for foreign language characters and
emojis, they developed a 16-bit character set called UNICODE.
A more developed version is UTF-32, which uses 32 bits…
268
User and Permissions Manager
User and Permissions Manager: One of the four managers
contained within the operating system. Controls user access
to files and settings. Working with the file manager, it
managers user accounts and who can view, open, edit and
delete files.
269
URL
URL: Universal Resource Locator: An address that allows the
user to access a resource on a WAN. Typically of the form:
https://www.bbc.co.uk/news
URLs contain the application layer protocol, the domain name
and a path.
270
Utility System Software
Utility System Software: Part of the Operating System. Helps
maintain and optimise the smooth running of the computer.
Includes the defragmentation tool, anti-malware, compression
tools, firewalls, backup and encryption software.
271
Validation
Validation: Checking that entered data is sensible and
matches input criteria.
272
Valid Data Test
Valid Data Test: When completing a Dry Run using a Trace
Table, the programmer will insert valid data (i.e data that
the program is expecting to receive) in order to check that the program correctly handles it. See also: Boundary Test,
Erroneous Test
273
Variable
Variable: A named memory location used to store a value in a
program
274
Virtual memory
Virtual memory: See: Swap file
275
Virus
Virus: A type of malware that infects a computer without the
user’s permission. Needs a host program to replicate itself
and spread across a network to computers without sufficient
anti-malware protection. May corrupt data, delete files or
provide a hacker with back-door access.
276
VLAN
VLAN: Virtual Local Area Network: A virtual LAN created
within a physical LAN; allows a school’s network
infrastructure to be split into different networks for pupils
and staff and provide different permissions for different
user groups.
277
Volatile
Volatile: A type of memory that can only function when it
receives electrical power. Then the power is switched off,
the data is lost.
278
VOIP
VOIP: Voice Over Internet Protocol: An application layer
protocol used for voice calls, e.g. Skype. The connection may
experience poor quality due to the nature of packet switching
data transmission and poor bandwidth
279
VPN
VPN: Virtual Private Network: A connection through a WAN to a
LAN to make it seem as though a client is located within the
LAN. Allows for remote working and is an alternative to using
the cloud. VPNs are also used by pupils to bypass school
firewalls and access questionable websites. See also:
tunnelling
280
WAN
WAN: Wide Area Network. A network of LANs, typically over a
large geographical area. The Internet is the world’s largest
WAN
281
WAP
WAP: Wireless Access Point: A hardware device that allows
wireless connections to a LAN. See also: Interference
282
Website
Website: A collection of World Wide Web pages hosted on a
server, accessible through the internet. Websites are
accessed by typing URLs into a web browser which begin with
the application layer protocol http(s)
283
White-hat Hacker
White-hat Hacker: A hacker who is employed by companies to
perform penetration testing on their networks, to seek out
vulnerabilities and report back any ways to improve security White hat hackers are often black hat hackers who turned away
from the dark side.
284
WiFi
WiFi: Wireless Fidelity: wireless communication across a
network. Usually the last stage of data transmission. Small
bandwidth and often prone to interference. WAPs transmit and
receive WiFi data packets on radio frequency channels.
285
Wildcard
Wildcard When using an SQL Command, to select all the fields
about an entry use an asterisk *
e.g. SELECT * FROM carTable WHERE price < 5000
286
Wireless
Wireless: A way of connecting to a LAN without cables. Allows
devices to be mobile, but susceptible to interference.
287
Worm
Worm: a piece of malware larger than a virus- it is a self-
contained program that can replicate itself, spread across a
network and infect other computers that do not have anti-
malware installed. Often slows computers down as it uses up
resources for malicious purposes. See also: Zombie computers
288
Zombie Computer:
Zombie Computer: A device infected with malware, often set up
to perform tasks for the hacker such as brute force attacks
or DDoS attacks.
