hardware and software

1. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Chapter 1B
Hardware and Software
Components

2. 2
Parts of the Computer System
• Computer systems have four parts
– Hardware
– Software
– Data
– User

3. 3
Parts of the Computer System
• Hardware
– Mechanical devices in the computer
– Anything that can be touched
• Software
– Tell the computer what to do
– Also called a program
– Thousands of programs exist

4. 4
Parts of the Computer System
• Data
– Pieces of information
– Computers organize and present data
• Users
– People operating the computer
– Most important part
– Tell the computer what to do

5. 5
Information Processing Cycle
• Steps followed to process data
• Input
• Processing
• Output
• Storage

6. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Hardware Components

7. 7
Essential Computer Hardware
• Computers use the same basic hardware
• Hardware categorized into four types

8. Hardware Components
Processing Devices
Memory Devices
Input and Output Devices
Storage Devices

9. 9
Input and Output Devices
• Input and output devices
– Allows the user to interact
– Input devices accept data
• Keyboard, mouse
– Output devices deliver data
• Monitor, printer, speaker
– Some devices are input and output
• Touch screens

10. 10
Memory Devices
• Memory devices
– Stores data or programs
– Random Access Memory (RAM)
• Volatile
• Stores current data and programs
• More RAM results in a faster system
– Read Only Memory (ROM)
• Permanent storage of programs
• Holds the computer boot directions

11. 11
Storage Devices
• Storage devices
– Hold data and programs permanently
– Different from RAM
– Magnetic storage
• Floppy and hard drive
• Uses a magnet to access data
– Optical storage
• CD and DVD drives
• Uses a laser to access data

12. 12
Processing Devices
• Processing devices
– Brains of the computer
– Carries out instructions from the program
– Manipulate the data
– Most computers have several processors
– Central Processing Unit (CPU)
– Secondary processors
– Processors made of silicon and copper

13. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Memory and Storage
Devices

14. Memory and Storage Devices
Primary Memory
• RAM
• DRAM
• SRAM
• ROM
Secondary Storage
• HDD
• SSD
Off-line Storage
• DVD/CD
• Blu-ray disks
• USB/ Flash memory
• Removable Hard Drive

15. RAM
The features of RANDOM ACCESS
MEMORY (RAM) are:
it is volatile/temporary memory (the
contents of the memory are lost when the
power to the RAM is turned off)
 it is used to store:
• data,
• files, or
• part of the operating system that are currently in
use
• it can be written to or read from and the contents of
the memory can be changed.

16. Types of RAM
RAM
DRAM SRAM

17. Dynamic RAM
DRAM needs to be constantly
REFRESHED (it needs to be recharged
every 15 microseconds otherwise it would
lose its value)
DRAMs have a number of advantages
over SRAMs:
• they are much less expensive to
manufacture than SRAM
• they consume less power than SRAM
• they have a higher storage capacity than
SRAM.

18. Static RAM
» A big difference between SRAM and
DRAM is that this type of memory
doesn’t need to be constantly refreshed
» SRAM is much faster than DRAM when
it comes to data access
» DRAM is the most common type of RAM
used in computers, but where absolute
speed is essential, then SRAM is the
preferred technology

19. ROM
The main features of READ ONLY MEMORY
(ROM) can be summarised as follows:
 they are non-volatile/permanent memories
(the contents of the memory remain even
when the power to the ROM is turned off)
 they are often used to store the start-up
instructions when the computer is first
switched on (for example, ROM might store
the basic input/output system (BIOS))
 the data or contents of a ROM chip can
only be read; they cannot be changed.

20. Application: Remote Controlled Toy Car
• ROM
• stores the factory settings such as remote
control frequencies
• stores the ‘start-up’ routines when the toy car is
first switched on
• stores the set routines; for example, how the
buttons on the hand-held device control turning
left, acceleration, stopping, and so on.
• RAM
• the user may wish to program in their own
routines; these new instructions would be stored
in the RAM chip
• the RAM chip will store the data/instructions
received from the remote control unit.

21. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Processing Devices

23. Control Unit
» Its like a supervisor of computer.
» CU control all activities of other parts of
computer.
» CU allow other parts of computer to
perform all activities correctly.
» CU reads instructions coming from main
memory and decodes these instructions.

24. ALU
» ALU perform arithmetic and logical
operations.
» ALU perform logical operation such as
compare two data items to find out which
is greater then, equal to or smaller then.
» ALU also perform arithmetic operations
such as addition, subtraction,
multiplication and division.

25. BUSES
» Buses essentially move data around the
computer and also send out control
signals to make sure everything is
properly synchronized.
» There are three types of buses
– Address Bus
– Data Bus
– Control Bus

26. BUS

28. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
McGraw-Hill Technology Education
Software Components

29. 29
Software Runs the Machine
• Tells the computer what to do
• Reason people purchase computers
• Two types
– System software
– Application software

31. 31
System Software
• System software
• System software is general purpose
software which is used to operate
computer hardware. It provides
platform to run application software
– Operating system
• Windows XP
– Utility
• Symantec AntiVirus

32. 32
Application Software
• Application software
– Application software is specific purpose
software which is used by user for
performing specific task
– Accomplishes a specific task
– Most common type of software
• MS Word, Excel, Real Player
– Covers most common uses of computers

33. System Software VS Application Software
1.
System software is used for
operating computer hardware.
Application software is used by user
to perform specific task.
2.
System softwares are installed on
the computer when operating
system is installed.
Application softwares are installed
according to user’s requirements.
3.
In general, the user does not
interact with system software
because it works in the
background.
In general, the user interacts with
application sofwares.
4.
System software can run
independently. It provides
platform for running application
softwares.
Application software can’t run
independently. They can’t run
without the presence of system
software.
5.
Some examples of system
softwares are compiler,
assembler, debugger, driver, etc.
Some examples of application
softwares are word processor, web
browser, media player, etc.