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Chapter 1 Computer Hardware
1
Computer Hardware
A level Computing Book (Reference)By P.M .Heathcore
Chapter 1 Computer Hardware
2
Computer System
Hardware Software
Chapter 1 Computer Hardware
3
DifferencesHardware 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 that what to do
It can not executed without hardware.
If any problem in software then it will reinstall.
Chapter 1 Computer Hardware
4
Computer Components
Logical units of a computer Input unit Output unit Memory unit ( Main Memory ) Central processing unit (CPU) Secondary storage unit
Chapter 1 Computer Hardware
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Computer Component
Input Unit
CPUUnit
Ram / Rom
ALU & LogicalUnit
Control Unit
Output Unit
Storage Devices
Chapter 1 Computer Hardware
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Types of computers by Size
Micro computers Mainframe Computers Super Computers Mini Computers Embedded Computers
Chapter 1 Computer Hardware
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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
Chapter 1 Computer Hardware
8
Types of Micro Computers Desktop Computers Laptop and notebook
Computers Personal Digital Assistants
(PDA) Palmtop Computers
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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.
Chapter 1 Computer Hardware
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Examples
IBM43810 NEC610 DEC 10 etc
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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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Uses
NASA Weather centre Stock Exchange Weapon design Mapping the surface of planets. Studying the neural network of brain Preparing models of chemical
systems.
Chapter 1 Computer Hardware
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Examples
CRAY-XP ETA-10 Blue sky ASCI White
Chapter 1 Computer Hardware
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.
Chapter 1 Computer Hardware
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Examples
Vax-8800 MV-1500
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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
Chapter 1 Computer Hardware
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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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Processors Most computer use Ics. It hold millions of electronic
components such as transistors
Chapter 1 Computer Hardware
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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.
Chapter 1 Computer Hardware
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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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Memory Sizes measurement
I nibble = 4 bits I byte = 8 bits I kilobytes (kb) = 1024 bytes 1 Megabytes (Mb) = 1024kilobytes 1 gigabytes (Gb) = 1024Megabytes 1 terabytes (TB) = 1024Gigabytes
Chapter 1 Computer Hardware
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Types of Main Memory
Ram (Random Access Memory) Rom (Read Only Memory)
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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)
Chapter 1 Computer Hardware
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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
Chapter 1 Computer Hardware
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How Cache memory Works
Processor
Cache Memory
Main Memory
Single Word of data Transferred
Block of data transferred
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CPUMemory
(main store)
Cachecontroller
Cachememory
Typically4MB
Typically64 KB
HitMiss
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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