CAT
NOTES
2021
,Module 1.1
Why we use computers:
• Efficiency (save time)
• Accuracy
• Reliability
• Communication
• Productivity
• Most cost effective
Computer systems factors:
• How powerful they are
• What they are used for
• Their Size (mobility)
• Software they use
Type of computer systems:
• Non-portable Computers = not move around, large, more powerful e.g.
Desktop Computer, Server, Entry-level computer
• Portable computers = move around, use traditional operating system, all in
one design e.g. Laptop, Tablet, Hybrid Computer, Smartphone, Phablet
Types of users:
1. Personal users = Independent on computers and don’t spend a lot of time
on computers
2. SOHO users (Small Office Home Office) = Depends on type of business
the user runs (usually entry-level) – uses printer and scanner
3. Power users = Computing needs that make hardware indispensable, top of
range hardware/software, has the best CPU and require more memory e.g.
Gaming computer
4. Mobile users = They want/need to have technology everywhere
Convergence = When one device, a smartphone, has all the technologies and
functions that required many different devices in the past e.g. Camera (for
photos), Music Player (for music)
Server = Powerful computer that provides resources/services to computers that
are linked together in a network
Entry-level computer = Cheapest in their Range, low hardware specifications
Module 1.2
, The information Processing Cycle:
Input ➡ Processing ➡
Output
⬆
⬇
⬇
Communication
Storage
Input = Provides/plans data, gathers data that needs to be processed. Decides
and creates data capture instructions. First step in information processing
system.
eg. mouse, keyboard, scanner, touchpad, digital camera, webcam,
microphone
Processing = Uses software/data loaded onto RAM or CPU to carry out tasks.
Converts data to information. Creates the output information by using algorithms
to solve problems.
Output = Sent directly to storage or other computers, shows what’s been
processed. Used as input for other programs.
eg. monitor or display, speakers and headphones, printers, data
projectors
Communication = Allows ICT devices to connect with each other
eg. cellular modem, ADSL and fibre route
*Cellular modem is cost effective, easier to carry around, more common*
Storage = Data is kept when computer is offline. Chooses correct storage
media, uses security to keep data safe, has backup polices. Non-volatile,
durable, higher capacity than RAM.
e.g. hard drive, external hard drive, flash drive, SSD, optical media
*External Hard drive = stores data or software permanently, also carries
media around, stores back-ups away from the PC*
ICT (Information Communication Technology) = Use multiple Input &
Output sources
*Touch screen is an input and an output device*
POS (Point of sale) = Specialised Keyboard, stores information onto system,
provides quick/accurate information
NOTES
2021
,Module 1.1
Why we use computers:
• Efficiency (save time)
• Accuracy
• Reliability
• Communication
• Productivity
• Most cost effective
Computer systems factors:
• How powerful they are
• What they are used for
• Their Size (mobility)
• Software they use
Type of computer systems:
• Non-portable Computers = not move around, large, more powerful e.g.
Desktop Computer, Server, Entry-level computer
• Portable computers = move around, use traditional operating system, all in
one design e.g. Laptop, Tablet, Hybrid Computer, Smartphone, Phablet
Types of users:
1. Personal users = Independent on computers and don’t spend a lot of time
on computers
2. SOHO users (Small Office Home Office) = Depends on type of business
the user runs (usually entry-level) – uses printer and scanner
3. Power users = Computing needs that make hardware indispensable, top of
range hardware/software, has the best CPU and require more memory e.g.
Gaming computer
4. Mobile users = They want/need to have technology everywhere
Convergence = When one device, a smartphone, has all the technologies and
functions that required many different devices in the past e.g. Camera (for
photos), Music Player (for music)
Server = Powerful computer that provides resources/services to computers that
are linked together in a network
Entry-level computer = Cheapest in their Range, low hardware specifications
Module 1.2
, The information Processing Cycle:
Input ➡ Processing ➡
Output
⬆
⬇
⬇
Communication
Storage
Input = Provides/plans data, gathers data that needs to be processed. Decides
and creates data capture instructions. First step in information processing
system.
eg. mouse, keyboard, scanner, touchpad, digital camera, webcam,
microphone
Processing = Uses software/data loaded onto RAM or CPU to carry out tasks.
Converts data to information. Creates the output information by using algorithms
to solve problems.
Output = Sent directly to storage or other computers, shows what’s been
processed. Used as input for other programs.
eg. monitor or display, speakers and headphones, printers, data
projectors
Communication = Allows ICT devices to connect with each other
eg. cellular modem, ADSL and fibre route
*Cellular modem is cost effective, easier to carry around, more common*
Storage = Data is kept when computer is offline. Chooses correct storage
media, uses security to keep data safe, has backup polices. Non-volatile,
durable, higher capacity than RAM.
e.g. hard drive, external hard drive, flash drive, SSD, optical media
*External Hard drive = stores data or software permanently, also carries
media around, stores back-ups away from the PC*
ICT (Information Communication Technology) = Use multiple Input &
Output sources
*Touch screen is an input and an output device*
POS (Point of sale) = Specialised Keyboard, stores information onto system,
provides quick/accurate information
