SECTION 1
Components of a Computer System
a) Define hardware, giving examples
Hardware is the term used for the parts of the computer that you can touch and
handle. Hardware is the collective name given to all the devices that make up a
computer system. Hardware includes:
CPU
Input devices (keyboard, CD-ROM drive or DVD, mouse, 3.5 inch floppy disk
drive, hard disk, scanners)
Backing storage – which consists of the disk drives used to store data when the
power is switched off. (DVD’s, CD-R’s, CD ROM, Magnetic tape, tape
cartridges)
Output devices (printers, VDU’s, speakers, 3.5 inch floppy disk drive)
b) Define software, giving examples
Software is the word used for the actual programs that allow the hardware the to a
useful job. Without software, hardware is useless. Software is made up of a series of
instructions that tell the computer what to do. To understand the difference between
software and hardware, think of a tape recorder and a blank tape. The tape recorder
and the tape are the ‘hardware’ because they are tangible (can be touched). However,
if we recorded some music onto the tape, then the music would be the ‘software’.
c) Describe the difference between hardware and software.
Hardware is tangible and software is not. Hardware refers to the physical components
which make up a computer system whereas software refers to the programs which are
run on the computer (Windows, Microsoft Office, Internet Explorer, Corel Draw).
d) Identify the main components of a general-purpose computer: central processing
unit, main/internal memory (including ROM and RAM, input devices, output
devices and secondary backing storage).
CPU (Central Processing Unit) – The ‘brain’ of the computer. The CPU processes
the raw data and turns it into information. There are three main elements of the
CPU;
- the control unit, responsible for coordinating the input and output devices
- the arithmetic and logic unit in which all the calculations and logical decisions
are made
- the immediate access store, which provides immediate memory for holding data
and programs.
Main/internal memory (including ROM and RAM)
- RAM is held on a chip but data in RAM is held only temporarily, which means
that the data disappears when the power is switched off. RAM is known as
volatile memory. RAM is used to hold both data and programs during processing.
- ROM is held on a chip inside the processor and is used to hold data which cannot
be changed by the user. Programs are stored on ROM chips when a computer is
manufactured. Usually, the data held on ROM will be the software that tells the
, computer how to load the operating system (called the boot program). Since data
is permanently stored on ROM it will stay stored even if the power is switched
off. ROM is referred to as non-volatile memory.
Input devices/output (see section a)
Secondary backing storage (see section a)
e) Identify operating systems, including Graphic User Interface, command line
interface.
Operating systems software is the instructions which control the general day to day
running of the computer. It looks after the way memory is organised schedules all the
tasks running on your computer and allows the user to communicate with the
computer. Sometimes the operating system comes together on one CD-ROM with the
user interface software (the user interface software is software which allows the user
to communicate with the operating system). Both are installed at the same time.
User interfaces
The user interface allows us to give commands to the computer. Today most personal
computers have GUI. The interface allows the user to communicate with the
computer’s operating system, so providing the user with overall control of the tasks.
A GUI is also known as a WIMP interface (Windows, Icons, Menus, Pointer) and this
is because each task is displayed in an individual window (which is basically a
rectangular box on the screen with a process’s output or folder’s contents displayed in
it. Windows can also display the contents of folders (directories), which may contain
software like a word processor or documents like a letter you wrote using the word
processor. A picture (icon) represents each item such as a document or piece of
software. An icon is just a small graphical picture. (Note that a folder usually contains
a selection of documents, programs/software and perhaps, other folders.
In addition, at the top of some windows you may see words which, when you clickon
them, give you a series of options to click on. These are called ‘pull down menus’.
Finally, the ‘Pointer’ referred to in a WIMP environment is the pointer displayed on
the screen as a result of moving the mouse. As the pointer moves over an object it is
possible to click and select that particular object.
, SECTION 2: INPUT DEVICES
Magnetic
Stripe
Digitiser Mouse OMR
Flat bed scanner Keyboard Microphone Joystick
Remote
control
Tracker ball Digital camera Hand held scanner
Graphics
MIDI tablet Sensor
MICR
Bar code
reader
Touch pad OCR Video camera
, INPUT DEVICES
1.
They contain their own chips. Each key acts as a switch which closes when the key is pressed
The microprocessor scans the keyboard hundreds of times a second to see if a key has been
pressed. If it has, a code that depends on which key has been pressed is sent to the processing
unit. The CPU translates this code into an ASCII (American Standard Code for Information
Interchange).
KEYBOARD
2.
An input device that translates its movements on the desktop into digital information
This is fed to the computer which in turn causes the cursor to move on the screen
MOUSE
3.
Is like an upside down mouse
The ball is rotated by the user but in this case the mouse stays still
TRACKER BALL
4.
Commonly found on notebook computers
You move your finger across the pad and this moves the cursor on the screen
MOUSE PAD
5.
A combination of hardware and software that converts an analogue video signal into a digital
signal in the computer’s memory
Each frame from a video is converted, using the video digitiser and it may be played back in any
required sequence
This is known as ‘image grabbing’ or ‘frame grabbing’
VIDEO DIGITIZER
6.
A device which acts as a communication line between the signals and the central computer
REMOTE CONTROL
7.
Similar to a tracker ball
Whenever the stick is moved, the cursor moves in a similar direction on the screen
JOYSTICK
8.
A short length of magnetic coating printed on to the surface of a ticket or card. The stripe usually
contains information to identify the ticket or card or its user. You can read the information on the
magnetic strip by ‘swiping’ card with a magnetic strip through a reader
MAGNETIC STRIPE
9.
A device used to examine pictures, text or other information and represent them as computer data
Two main types:
A hand held device which is moved across the picture
A flat bed scanner. Picture is laid flat and the scanner remains stationary on a table while picture
is scanned
Components of a Computer System
a) Define hardware, giving examples
Hardware is the term used for the parts of the computer that you can touch and
handle. Hardware is the collective name given to all the devices that make up a
computer system. Hardware includes:
CPU
Input devices (keyboard, CD-ROM drive or DVD, mouse, 3.5 inch floppy disk
drive, hard disk, scanners)
Backing storage – which consists of the disk drives used to store data when the
power is switched off. (DVD’s, CD-R’s, CD ROM, Magnetic tape, tape
cartridges)
Output devices (printers, VDU’s, speakers, 3.5 inch floppy disk drive)
b) Define software, giving examples
Software is the word used for the actual programs that allow the hardware the to a
useful job. Without software, hardware is useless. Software is made up of a series of
instructions that tell the computer what to do. To understand the difference between
software and hardware, think of a tape recorder and a blank tape. The tape recorder
and the tape are the ‘hardware’ because they are tangible (can be touched). However,
if we recorded some music onto the tape, then the music would be the ‘software’.
c) Describe the difference between hardware and software.
Hardware is tangible and software is not. Hardware refers to the physical components
which make up a computer system whereas software refers to the programs which are
run on the computer (Windows, Microsoft Office, Internet Explorer, Corel Draw).
d) Identify the main components of a general-purpose computer: central processing
unit, main/internal memory (including ROM and RAM, input devices, output
devices and secondary backing storage).
CPU (Central Processing Unit) – The ‘brain’ of the computer. The CPU processes
the raw data and turns it into information. There are three main elements of the
CPU;
- the control unit, responsible for coordinating the input and output devices
- the arithmetic and logic unit in which all the calculations and logical decisions
are made
- the immediate access store, which provides immediate memory for holding data
and programs.
Main/internal memory (including ROM and RAM)
- RAM is held on a chip but data in RAM is held only temporarily, which means
that the data disappears when the power is switched off. RAM is known as
volatile memory. RAM is used to hold both data and programs during processing.
- ROM is held on a chip inside the processor and is used to hold data which cannot
be changed by the user. Programs are stored on ROM chips when a computer is
manufactured. Usually, the data held on ROM will be the software that tells the
, computer how to load the operating system (called the boot program). Since data
is permanently stored on ROM it will stay stored even if the power is switched
off. ROM is referred to as non-volatile memory.
Input devices/output (see section a)
Secondary backing storage (see section a)
e) Identify operating systems, including Graphic User Interface, command line
interface.
Operating systems software is the instructions which control the general day to day
running of the computer. It looks after the way memory is organised schedules all the
tasks running on your computer and allows the user to communicate with the
computer. Sometimes the operating system comes together on one CD-ROM with the
user interface software (the user interface software is software which allows the user
to communicate with the operating system). Both are installed at the same time.
User interfaces
The user interface allows us to give commands to the computer. Today most personal
computers have GUI. The interface allows the user to communicate with the
computer’s operating system, so providing the user with overall control of the tasks.
A GUI is also known as a WIMP interface (Windows, Icons, Menus, Pointer) and this
is because each task is displayed in an individual window (which is basically a
rectangular box on the screen with a process’s output or folder’s contents displayed in
it. Windows can also display the contents of folders (directories), which may contain
software like a word processor or documents like a letter you wrote using the word
processor. A picture (icon) represents each item such as a document or piece of
software. An icon is just a small graphical picture. (Note that a folder usually contains
a selection of documents, programs/software and perhaps, other folders.
In addition, at the top of some windows you may see words which, when you clickon
them, give you a series of options to click on. These are called ‘pull down menus’.
Finally, the ‘Pointer’ referred to in a WIMP environment is the pointer displayed on
the screen as a result of moving the mouse. As the pointer moves over an object it is
possible to click and select that particular object.
, SECTION 2: INPUT DEVICES
Magnetic
Stripe
Digitiser Mouse OMR
Flat bed scanner Keyboard Microphone Joystick
Remote
control
Tracker ball Digital camera Hand held scanner
Graphics
MIDI tablet Sensor
MICR
Bar code
reader
Touch pad OCR Video camera
, INPUT DEVICES
1.
They contain their own chips. Each key acts as a switch which closes when the key is pressed
The microprocessor scans the keyboard hundreds of times a second to see if a key has been
pressed. If it has, a code that depends on which key has been pressed is sent to the processing
unit. The CPU translates this code into an ASCII (American Standard Code for Information
Interchange).
KEYBOARD
2.
An input device that translates its movements on the desktop into digital information
This is fed to the computer which in turn causes the cursor to move on the screen
MOUSE
3.
Is like an upside down mouse
The ball is rotated by the user but in this case the mouse stays still
TRACKER BALL
4.
Commonly found on notebook computers
You move your finger across the pad and this moves the cursor on the screen
MOUSE PAD
5.
A combination of hardware and software that converts an analogue video signal into a digital
signal in the computer’s memory
Each frame from a video is converted, using the video digitiser and it may be played back in any
required sequence
This is known as ‘image grabbing’ or ‘frame grabbing’
VIDEO DIGITIZER
6.
A device which acts as a communication line between the signals and the central computer
REMOTE CONTROL
7.
Similar to a tracker ball
Whenever the stick is moved, the cursor moves in a similar direction on the screen
JOYSTICK
8.
A short length of magnetic coating printed on to the surface of a ticket or card. The stripe usually
contains information to identify the ticket or card or its user. You can read the information on the
magnetic strip by ‘swiping’ card with a magnetic strip through a reader
MAGNETIC STRIPE
9.
A device used to examine pictures, text or other information and represent them as computer data
Two main types:
A hand held device which is moved across the picture
A flat bed scanner. Picture is laid flat and the scanner remains stationary on a table while picture
is scanned
