Crunch Notes Grade 11 Flashcards
BIOS
Basic Input Output System – the essential start-up
instructions of a computer, in ROM chips on the
motherboard, and representing the lowest level of
programming firmware.
BUS
A set of electrical paths etched on a motherboard, used to
transfer data between different parts, e.g. between an
expansion card and RAM.
Caching
A method used to compensate for the loss of efficient, or
‘bottleneck’, that becomes inevitable when a faster medium
tries to communicate with a slower medium.
CMOS
Complementary Metal Oxide Semiconductor – the type of
memory that stores the BIOS settings that can be updated or
changed. This memory is kept ‘alive’ by a small battery on
the motherboard.
CPU
Central Processing Unit – a chip that can contain more than
on ‘core’ (complete processor) and which connects to the
motherboard using the ZIF socket. Responsible for all the
processing.
CPU Cache
Special type of high-speed memory built into the CPU, used
to maximise CPU productivity.
Disk Cache
A certain amount of high-speed memory built into every
hard drive. Used to cache data from the (slower) disk, and
thereby speed up subsequent calls for the same ‘chunk’ of
code or data.
EEPROM
Electronically Erasable Programmable Read Only Memory –
a type of ROM that can be erased electronically, after which
a new ‘image’ of upgraded contents can be written back.
Expansion slots
Slots on the motherboard for attaching additional circuit
boards in order to ‘expand’ the capabilities of the computer
– mostly dedicated video and sound cards for high-end
gaming and design work.
External Connectors
Situated both ad the bac and the front of the casing, e.g USB
ports, VGA port for monitor, RJ45 port for Ethernet network
cabling, speaker and microphone jacks, ect.
Firewire
A type of port that can transfer data faster that USB. It
usually used where high speed data transfer is desirable,
such as videos from a video camera, and data to or from an
external hard drive.
Firmware
Software that is permanently installed, or ‘hard-coded’ on a
ROM chip, and used to control the basic operation of a
device, e.g a printer.
Flashing the ROM
The process whereby the existing contents of firmware is
wiped and replaced with an updated version – always to be
performed with great care.
GPU
Graphics Processing Unit – dedicated graphics processor on
a graphics card, used to provide extra processing power.
Hardware Interrupt (IQR)
A dedicated communication channel, or means, whereby a
device can request the immediate attention of the CPU, in
order to process a given function, e.g a mouse click or a
keystroke.
Machine Cycle
Steps taken by the CPU in carrying out instructions:
Fetching instructions and data from the
memory (RAM)
Decoding the instructions
Executing the instructions
Transferring data back to the memory
Point-To-Point connections
Dedicated connection between two components (e.g
between RAM and CPU that is not shared with other
components.
POST
Power On Selft Test – start-up test performed by the Bios to
ensure that all essential hardware (RAM, keyboard ect) is
present and in working order.
SATA Connectors
Connectors on the motherboard for attaching cables for
storage devices, such as hard drives and optical drives.
System Clock
A small quartz crystal that pulses at a regular frequency
measured in GHz; used to coordinate activates on a
motherboard.
Thunderbolt
A new superfast connection technology, which can support
multiple simultaneous connections.
USB
Universal Serial Bus – the most widely used connection
option for attaching devices to a computer, via a USB port.
Web caching
The process of storing recently accessed web pages locally
on the relatively much faster hard drive so that they are
quicker to retrieve the next time they are needed. Retrievals
from local storage are much faster than Internet downloads.
ZIF socket
Zero Insertion Force – a type of socket on the motherboard
for connecting a CPU.
API
Application Programming Interface – an interface between
the operating system and the programming language / end
user.
Assembler
A program that translates assembler code to machine code.
Compilers
Software that translates programming instructions written in
a high-level language into standalone ‘executable files’ (with
an .exe extension) that can be run independently of the
programming language or compiler.
High-Level Programming languages
Programming languages that are easier for humans to write
and understand, that rely on extensive pre-written libraries
to execute complex instructions with just a few lines of code.
Interpreters
Software that translates programming instructions into
machine code one line at a time. Does not generate
executable files. Programs written for interpreters can only
run if the interpreter (or a special ‘runtime’ module of the
interpreter) is installed on the computer.
Low-level programming languages
Assembler type languages that typically use fewer
commands, but correspondingly more simple instructions, to
produce very fast and efficient code.
Machine code
Instructions in binary format (0’s and 1’s) that the CPU can
directly execute.
Multiprocessing
The type of processing that takes place when the operating
system divides the programs/threads/processes between
multiple CPUs (Physical chips or cores).
Multitasking
The operating system splits the CPU time between multiple
programs, and so the computer seems to be doing more
than one task at a time.
Multithreading
The ability of an operating system to allow programs to split
themselves into multiple tasks (or threads) that can be run
at the same time.
Process Management
The task of making sure that each process gets enough CPU
time and access to hardware resources so that it can work
without interfering with or being interfered with by other
processes.
Thread
A part of a larger program that runs independently by
simultaneously with other parts of the same program.
Virtual Memory
An area of storage or disk space that the operating system
keeps for its own use.
Virtualisation
Creating an entity (memory, storage, machine ect) that only
exists in software.
Biometric security
Security based on measurement and identification of unique
physical characteristics of a person, e.g fingerprints.
Data validation
Checking for the correctness of data from a computer
perspective, i.e with reference to a defined set of criteria, or
allowable values, which the computer program will either
accept or reject.
Data verification
Checking for the accuracy of data from a human perspective.
Defensive programming
A technique whereby the programmer makes pro-active
provision for possible errors made by the user, in the
interest of correct data entry.
Disk imaging
Creating a backup ‘image’ of the entire hard drive, including
all data and programs, to be used for re-installation in the
case of complete hard drive failure.
Encryption
The ‘scrambling’ of text or data according to a specified set
of rules to ensure the privacy of data during communication,
or for security purposes.
Firewall
Hardware or software that monitors the traffic between a
computer and the internet, to safeguard against breaches in
security.
GIGO
‘Garbage In, Garbage Out’ the quality of the output for any
computer system is directly related to the quality of the
input.
Incremental backup
Backup schedule whereby backups are made only on new
files and files that have changed since the last backup,
resulting in greater backup efficient (saving in disk space and
backup time), and allowing selective data recovery from an
earlier date.
Malware
Malware (malicious software) is a general term used to
describe malicious software that is specifically designed to
install itself without the user’s knowledge to negatively
affect or ‘harm’ a computer system.
Online backup
The backing up of data on a server on the Internet (‘the
cloud’), with the advantages of data synchronisation, sharing
and portability.
Raid
Redundant Array of Inexpensive/Independent Disks – the
configuration of two or more hard drives, designed to
minimise the possibility of data loss.
Rootkit
Collection of programs designed to use administrator rights
to gain and control of a computer for dangerous purposes.
Social Engineering
Any attempt to manipulate or ‘con’ someone into installing
malware or giving out sensitive or personal information.
Software bug
A logical programming error that can cause unexpected
program behaviour, incorrect output or invalid data
processing.
Spyware
A form of malware that tries to monitor and track the way
you use your computer to discover confidential information,
and then relay this to a third party.
Trojan
A form of malware disguised as a useful program, but in
reality designed to do harm.
UPS
Uninterruptible Power Supply – a hardware device used to
protect against power supply problems, consisting
essentially of a constantly charged battery between the
computer and the wall plug.
Access Point
Also called a base station, consists of a server/transceiver
and an antenna, which transmits and receives radio waves
so that the devices that are wireless enabled are able to
communicate with one another and the network.
HAN
Home Area Network - A small network within a home environment.
Hotspot
An area, usually in a public space such as an airport,
restaurant or hotel lobby, where people may receive and be
granted WiFi access from an access point to connect
wirelessly to the Internet via a wired network.
Location Based computing
Computing where the physical location of objects and
people are determined and used.
Network Interface controller
A device that allows a computer to communicate with a
network either wirelessly or via a cable connecting the
network to the NIC in the computer.
PAN
Personal Area Network - A computer network with a range of a few metres that is organised around an individual.
Topology
The layout of the physical connection of the computers in a
network.
VPN
A network implemented via a public network such as the
Internet. This enables the user to log onto a network from a
remote location with the same benefits of privacy and
security as a LAN.
VoIP
A protocol or special set of rules for communication
between devices that allows telephone calls to be made
over LANs, WANs and the Internet.
WLAN
A method of connecting to an existing network wirelessly, by
using radio waves to send and receive data.
WiMax
An upgrade of WiFi technology, allowing for more secure
communication over a wider area.
WLAN
A LAN which uses wireless technology (radio waves) rather
than cables to communicate.
Blogs
Websites updated regularly with news and events in
chronological order. A blog reads like a journal with the most
recent entry at the top.
Bluetooth
A wireless technology that allows devices such as mice,
printers and cell phones to communicate over a relatively
short distance, typically less than 10m.
GPS
Global Positioning System - A navigation system that uses signals received from geo-stationary satellites to determine accurately within 5m) the position of a receiving device.
HTTPS
HyperText Transfer Protocol Secure - The protocol used for secure, encrypted communications over the internet. It is used on websites, which require a user to enter confidential or personal information such as passwords or banking details.
IM
Internet based alternative to text messaging, in which
multimedia content can be exchanged in real time via
applications such as WhatsApp, BBM and Mxit.
Microblogging
The posting of short text entries usually via a cellphone or a
smartphone, on a platform like Twitter.
Mobile Browser
Browser designed for the use on mobile devices,
incorporating innovations to accommodate the smaller
screen sizes, also the lower power profiles and processing
abilities of these devices.
Podcast
An audio file (often in MP3 format) made available for
download from the Internet; more often pre-recorded radio
chat shows and talks, rather than music.
POP3
Post Office Protocol 3 - The most common protocol used for downloading e-mail via the Internet from POP3 servers.
Protocol
A set of rules for encoding and decoding data for
transmissions across a network.
Smartphones
Cellphones with a mobile operating system and the ability to
run third-party software or ‘apps’. They generally include a
touch screen interface and multiple sensors for advanced
functions such as GPS, accelerometer, ect.
SMS
Short Message Service - SMS-ing (or texting) is sending short text messages from one cell phone to another, popular and convenient because it allows one to communicate directly without making a phone call.
SMTP
Simple Mail Transfer Protocol
The most common protocol used for sending e-mail via
SMTP servers on the Internet.
Vlog
A form of blog, which uses video as the medium. Entries
normally combine video supported by text and images.
Vodcast
A form of podcast which includes video clips or photos and is
downloaded and played as a movie.
Audio and Video On Demand (AVOD)
Video on Demand (VOD) and Audio and Video on Demand
(AVOD) are systems which allow users to watch video
content and listen to audio content on demand.
Downloading
Transferring and saving an audio or video file from the
Internet onto a computer, smartphone or tablet. You can
then play the file at a later stage, or more than once,
without being connected to the Internet.
Fixed location internet access
High speed data transmission to homes and businesses using
cabled technologies such as ADSL. This is often referred to as
a fixed broadband access.
Internet Protocol television (IPTV)
The delivery of television services over the Internet instead
of through traditional satellite systems such as South Africa’s
DSTV.
JPEG
The most common file format used for digital photos or
graphics, also widely used for graphics on websites. (JPEG
files are also known as JPG files.)
Live broadcasts
The broadcasting (Streaming) of different types of media in
real-time without any significant delay, allowing users to
witness events as they are happening.
Lossless compression
Compressing data without losing any portion of the data. It
allows the exact original data to be reconstructed.
Lossy compression
Compressing data by sacrificing some insignificant or
virtually indetectable portion of the data.
Mobile internet access
The ability to connect to the Internet using wireless
networks such as the cellular phone network. This is often
referred to as mobile broadband Internet Access.
MP3 (MPEG-1 Audio Layer-3)
The most common digital music file format, combing
efficient compression with excellent sound quality. The
current standard for storing digital music.
MPEG
Moving Picture Experts Group
A reference to the digital compression standards and file
formats developed by the group.
MPEG - 2
A standard used for the compression of video files and their
associated audio tracks, and widely used to broadcast digital
television.
MPEG - 4
The latest and still developing standard used for the
compression of audio and visual digital data through the use
of lossy compression.
Streaming
The immediate and real-time delivery of media content to a
receiving device, starting from the time at which the media
file is opened. The file is not saved to your device.
Web 1
Earliest stage in the evolution of the WWW, characterised by
mostly static content and a ‘read-only’ role on the part of
the consumer public.
Web 2
The next, and current stage in the evolution of the WWW,
characterised by more dynamic content and an interactive
‘read-write’ role on the part of the consumer public. Content
consumers can become content creators as well, for
example, on social networking sites.
Web 3
The future of the WWW, in which exact directions are still
uncertain, but which will certainly contain elements of
artificial intelligence and a greater emphasis on personalised
content; in other words less ‘reaction’ and more customised
‘prediction’ in favour of users. Web 3.0 will also be
accompanied by enhancements in web-enabled devices,
elimination of incompatibility issues, extensions in mobile
capacity and increases in bandwidth and speed.
Webinars
Online seminars, which users in remote locations can
participate in, using online conference technologies. These
occur in real-time and allow ‘delegates’ access to interactive
conferences and workshops.
WWW
A service on the Internet. The WWW consists of a vast global
collection of interlinked, Interactive multimedia documents.
DNS
Domain Name System
An Internet service that translates domain names to IP
addresses. Domain names consisting of words are easier to
remember than IP addresses. The Internet is based on IP
addresses. When you use a domain name, a DNS service
must translate the name into the corresponding IP address.
Dynamic Website
A website consisting of web pages designed to be generated
‘on the go’ and which may differ each time, based on who
the user is and what their recorded preferences and options
are.
RIA (Rich Internet Applications)
A web application that is designed to deliver the functions
and features of a traditional desktop application. Web
browsers are required for access. Unlike traditional
applications, the installation of software is not needed.
RSS (Really Simple Syndication)
A web or news feed that automatically provides users with
updated content or notifications of new content. This
content can then be accessed from a central application
without having to check each and every website.
SEO (Search Engine Optimisation)
A strategy or technology used to obtain a high-ranking
placement in the search results page of a search engine such
as Google.
Static Website
A website consisting of multiple pages – each a single file
that displays exactly the same information every time to the
user just as when it was created.
AUP
Acceptable Usage Policy – a document drawn up by the
stakeholders concerned, e.g The Governing Body of a school
that outlines the rights and responsibilities of users within a
network environment including the consequences violating
these stipulations.
Network Use Policies
Software settings defined by the network administrator in
server operating systems, e.g Windows Server 2012, to
control what users can and cannot do with the network.
Artificial Intelligence
Simulation of human decision-making processes by a
computer system that is programmed to react based on
input gained from sensors.
Decentralisation of labour
Concept whereby ICT has made it possible for people to
work from remote locations, instead of being tied to a
specific central location.
Graphic Designer
Someone who designs the ‘look’ of a product or solution,
such as the physical packaging, or the visual/spatial aspects
of a program or website.
Mobile Office
A concept whereby the tools of your business, e.g your
tablet and smartphone, are carried around with you,
allowing you to perform common office functions while ‘on
the move’.
Network Administrator
Someone who manages a network from the software
perspective, typically working on a server and using the
management tools provided by a network operating system,
e.g Windows Server 2012
Office Automation
Process whereby certain routine office processes are carried
out without human intervention.
Outsourcing
Contracting specialist businesses to run aspects of your own
business that are essential for proper functioning, but that
do not fall within your own area of expertise.
PC Technician
Someone who assembles, upgrades and repairs computer
hardware.
Programmer
Someone who writes code to create or maintain software,
often as part of a team with other programmers and IT
specialists.
Robotics
Performance of physical tasks, commonly repetitive or
dangerous ones, by computer-controlled machines rather
than by human beings.
Security Consultant
Someone who critically evaluates the security aspects of a
business, then designs or recommends appropriate
solutions.
Systems analyst
Someone who performs the ‘Interface’ function between
client and programmer, analysing the requirements of the
client as a list of specifications for the programmer, who will
ultimately create the software solution.
Telecommuting
Working in decentralised locations, e.g from home, but using
modern communication occasionally to ‘check in’ at the
physical office.
Virtual Office
A fixed physical address, containing minimal office setup
such as a reception desk and meeting room, which is used as
a shared space by people who otherwise work from a mobile
office.
Web Author
Someone who uses a variety of tools to plan, structure,
create and maintain a website.
Accuracy
This refers to the fact that the data is ‘right’.
Alternate Key
A field that identifies each record with a unique value but is
not used as the primary key.
Completeness
This refers to how comprehensive the data is.
Correctness
This refers to data being ‘logically correct’ or ‘reasonable’.
Currency
This relates to how ‘recent’ or up to date the data is.
Database
A collection of data or facts regarding a specific topic, e.g
details of a CD collection or details concerning clients.
Field
A single fact or the smallest unit of data.
Primary Key
A field that identifies each record with a unique value.
Query
Extracting information according to specified criteria.
Record
A collection of fields that contains details on a specific entity.
Relevance
This relates to how closely the data matches your needs.
Table
Grouping related records in a table where each row
represents a record, and each column a field.
Database administrator
A person who is responsible for managing and maintaining
databases (usually via DBMs). This involves the allocation
and supervision of users of the database and their access
rights, as well as performing routine maintenance on the
database.
Database Analyst
A person who is concerned with issues such as the need to
make changes to the underlying database structure,
analysing the efficiency of the system and analysis and
design activities in terms of the new developments and
maintenance of the database.
Database Management System
Software that allows you to work with electronic databases.
Examples are Microsoft SQL Server, Oracle, Microsoft
Access, Blackfish and MySQL.
Database Programmer
A person who is responsible for coding the custom-made
software that is the user interface to the database.
Desktop Database
Database software where the tools that you need to work
with the data are included in a single application and you
need to start that application to be able to work with the
database.
Distributed Database
A system where parts of a database (the data and the DBMS)
are spread (distributed) across servers in separate locations.
Project Manager
A person who plans and sets out goals on a timeline to
oversee the progress of a project from beginning to end.
Server DBMS Software
Database software that is installed on a server and is never
directly accessed by the user but accessed by custom
written client software or applications.
Unix Administrator
A person who is responsible for installing, configuring and
troubleshooting the DBMS that runs on a Unix operating
system.
Anomalies
Problems or errors that occur when you try to insert data,
delete data or update data.
Composite Keys
The combination of more than one field to uniquely identify
a record.
Data Independence
The same application can be used for data stored on
different media (physical independence), and the application
will not be affected when you add a table to a database or
create extra fields in existing tables (logical independence).
Data Integrity
The overall completeness, accuracy and consistency of data.
Data integrity is ensured when each record has its own
unique primary key and when a foreign key refers to an
existing record in another table.
Data maintenance
Adding or deleting records, or updating data.
Data Redundancy
The unnecessary repetition of data.
Data Security
The protection of databases against unauthorised access by
users.
ER Diagrams
Diagrams used to illustrate relationships between entities.
Foreign Keys
A field (not a primary key) that is used as a ‘link’ to a field in
another table (usually the primary key).
Relational Database
A database containing many tables linked together in
relationships.
