3. Differences
Hardware
• Physical Component of a
Computer
• We can touch these parts
• Allow user to enter data and
information into computer and
retrieve
• Can not perform any task
without Software
• If problem occur in hardware
then it will repaired.
Software
• Logical Component of a
Computer
• We can not touch
• These are in form of instructions
that tell the computer what that
to do
• It can not executed without
hardware.
• If any problem in software then
it will reinstall.
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4. Computer Components
• Logical units of a computer
• Input unit
• Output unit
• Memory unit ( Main Memory )
• Central processing unit (CPU)
• Secondary storage unit
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5. Computer Component
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Input Unit
CPU
Unit
Ram / Rom
ALU & Logical
Unit
Control Unit
Output Unit
Storage Devices
6. Types of computers by Size
• Micro computers
• Mainframe Computers
• Super Computers
• Mini Computers
• Embedded Computers
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7. Micro Computers
• Are the computers that you are most likely to encounter
at home or in school and colleges.
• It consist of one or more input device ,output device,
memory and processor.
Examples
• PCs
• Apples
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8. Types of Micro Computers
• Desktop Computers
• Laptop and notebook Computers
• Personal Digital Assistants (PDA)
• Palmtop Computers
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9. Mainframe computers
• Thousands of terminals attached to it.
• Larger mainframe computers carry out 250 million
instructions per second.
• It Consist of multiple processors.
• Used large organizations such as banks, insurance
companies, airlines and government department.
• Disadvantage:
• Due to immense power they produce large amount
of heat so its require air conditioned.
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11. Supercomputers
• Largest category of computer, costing millions of
pounds.
• It is complex ,large storage and advanced computers.
• They are mostly used by scientific and industrial
research departments.
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12. Uses
• NASA
• Weather centre
• Stock Exchange
• Weapon design
• Mapping the surface of planets.
• Studying the neural network of brain
• Preparing models of chemical systems.
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14. Mini computers
• Have a size , power and cost somewhere between
those of microcomputers and mainframes.
• It is much powerful then some of the mainframes
still in use.
• It is used by business institutes and departments.
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16. Embedded Computers or
Microprocessors• Is a single chip that perform the functions of a
central processing unit
• Many microprocessors makes are Microcontrollers
also called embedded.
• Embedded computers serve as the brain of a larger
piece of machine.
• Their software is stored in the computer’s own.
• They serve as a personal computer but not have a
monitor, keyboard and mouse
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17. Uses
• Microwaves programmable ovens
• Blood pressure monitors
• Air bag sensors
• Washing machines
• Video recorders
• Alarms
• Digital cameras
• MP3 players
• Car engine Controllers
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18. Processors
• Most computer use Ics.
• It hold millions of electronic components such
as transistors
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19. Functions
• It controls the transmission of data from input
device to memory
• It processes the data held in main memory
• It controls the transmission of information from
main memory to output device.
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20. Main Memory
• Instructions and data are held in main memory which
is divided into millions of addressable storage units
called bytes.
• One byte can hold one character
• Total bytes in main memory referred to as the
computer’s memory size.
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22. Types of Main Memory
• Ram (Random Access Memory)
• Rom (Read Only Memory)
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23. RAM & ROM
Ram
• Its temporary memory
• Read and Write data
• Data can be changed or
deleted
• It is a Volatile memory
• The instructions written in
Ram at the time of execution
Rom
• Its Permanent memory
• It can only be read
• Data can not change or deleted
• It is non Volatile
• The instructions are written into
Rom at manufacturing time.
(BIOS)
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24. Cache Memory
• A Cache is a small and very fast memory
• To speed up the transfer of data and
instructions.
• It is located inside or close to the CPU Chip.
• It is faster than Ram
• The data and instructions that are most recently
or most frequently used by CPU are stored in
cache.
• The amount of cache memory is generally
between 1kb and 512kb
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25. How Cache memory Works
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Processor
Cache Memory
Main Memory
Single Word of data Transferred
Block of data transferred
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CPU
Memory
(main store)
Cache
controller
Cache
memory
Typically
4MB
Typically
64 KB
HitMiss
27. Disk Storage
• The most common form of auxiliary
storage ( External or secondary or
backing store) is disk
• Magnetic media
• Hard disk
• Tape
• Floppy disk
• Optical storage device
• CD
• DVD
• CD-R
• CD-RW
• CD-ROM
• USB Drive
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