One would expect any spreadsheet package to have the following functions:
There are advantages and disadvantages to using spreadsheet software.
Database software
The main use of this software is to store, organise, and retrieve information.
Examples of use include:
- library book loaning
- video rental
- school pupil information
One would expect any database package to have the following functions:
There are advantages and disadvantages to using spreadsheet software.
Desktop publishing software
The main use of this software is to create documents that contain many graphics and some text.
Examples of use include:
- posters
- catalogues
- invitations
- newsletters
One would expect any desktop publishing package to have the following functions:
There are advantages and disadvantages to using spreadsheet software.
Presentation software
The main use of this software is to animated visual presentations.
Examples of use include:
- presentations for meetings
- computer-based help systems
Graphics software
There are two types of graphics packages.
Bitmap graphics software stores images as lots of coloured dots, known as pixels.
Vector based graphics software stores images as rules, covering the dimensions, direction, and colour of the drawn object.
Computer aided design (CAD) software
The main use of this software is to design three dimensional objects.
HTML editing software
The main use of this software is to create web-pages.
Communications software
There are two types of communications software.
Electronic mail, used to send and receive messages.
Web-browser software to view web pages on the Internet.
Integrated software
A software package that combines the functions of two or more distinct generic applications.
Specific software
Software designed to carry out a single task for users.
System software
Software that manages and controls the computer and all its peripherals.
Operating system software
A layer of software that enables a user to control the hardware, and application programs to run on the computer.
Utility software
Software used to carry out routine tasks often needed by the user to maintain the performance of the computer.
Hardware
Hardware is the name given to any part of the computer that you can actually touch.
A device is an individual piece of hardware.
Examples include:
- keyboard
- visual display unit (VDU) or monitor
- floppy disk drive
Describing hardware
Technical specification
This is a list of its properties. It usually refers to the performance and/or capacity of the device.
Performance
This is a way of describing how well a device in a computer system does its job. This often refers to the speed at which it works.
Capacity
This is the amount of data that can be stored.
Processor
The central processing unit (CPU) is the part of the computer where the searching and sorting of data, calculating and decision-making goes on.
Also known as the ‘processor’.
Choosing a processor
Processors are measured by their speed.
The number of instructions it can perform in 1 second.
This is measured in hertz (Hz).
1 hertz = 1 instruction per second
1 KHz = 1,000 instructions per sec
1 MHz = 1,000,000 instructions per sec
1 GHz = 1,000,000,000 instructions per sec
Input devices
Input devices are used to enter commands or information into a computer.
Examples of input devices include:
- keyboard
- mouse
- scanner
- microphone
- trackball
- joystick/ joypad
- graphics tablet
- digital camera/ web-camera
Output devices
Output devices are used by the computer to communicate information to human users or to affect a change in a physical environment.
Examples of output devices include:
- VDU/monitor
- printer
- speakers
Types of VDUs/monitors
Choosing VDUs/monitors
Type
cathode ray tube (CRT) or liquid crystal display (LCD) (thin-film transistor [TFT])
Colour
monochrome, or grey-scale, or colour
Resolution
measured in pixels; 640 X 480 (VGA), 800 X 600 (SVGA), 1024 X 768 (XVGA or XGA)
Size
diagonal distance, from one corner to another (inches)
Types of printers
Choosing printers
Speed
characters per second (cps) or pages per minute (ppm)
Quality
dots per inch (dpi)
Colour
monochrome, or colour
Data storage devices
Storage devices are used to store the programs and data needed by the computer.
The two main categories of storage devices are main memory and backing storage.
Main memory
RAM – random access memory
RAM is used by the computer to store the programs and data that are being used at a given time.
RAM is ‘volatile’ which means that when the computer is turned off all its contents are wiped clean.
Choosing RAM
RAM is measured by its capacity; the amount of data that it can store when the computer is switched on.
All computers ultimately store data as 1s and 0s (this number system is known as binary).
A single unit (either 1 or 0) is called a bit.
8 bits = 1 byte 1,000 bytes = 1 KB
1,000 KB = 1 MB 1,000 MB = 1 GB
Backing storage
Backing storage is used to store programs and data when they are not being used or when the computer is switched off.
Backing storage is ‘non-volatile’ which means that when the computer is turned off none of its contents are lost.
backing storage device – used to read and write data onto storage media.
backing storage media – the collective name given to the disks and tapes used to store data.
Choosing backing storage
The first decision is between fixed media or removable media.
Backing storage media can be measured by its capacity; bytes, or kilobytes (KB), or megabytes (MB), or gigabytes (GB).
Backing storage can also be judged by the data transfer speed of the backing storage device to the backing storage media. This is measured in; bytes per second (Bps), or kilobytes per second (KBps), megabytes per second (MBps).
Audio CDs read at 150KBps – 8X, 16X, 24X, 48X, 52X.
The final way that backing storage can be differentiated is whether it is:
- read only memory (ROM), or
- recordable (R)/ write once read many (WORM), or
- read and write (RW).
Types of portable backing storage
- floppy disk drive (FDD)
- compact disk (CD) drive
- Zip drive
- digital versatile disk (DVD) drive
- flash stick
Computers and peripherals
Desktop computer
An entire computer that sits on a desk or a table.
Laptop computer
A personal computer that can be simply carried around by one person and used in transit from internal battery power.
Peripherals
Social Impact
In the home
In business
