Parts of the Computer System

CompanyCompany

LOGOLOGO

Looking Inside the Computer Looking Inside the Computer

Lecture 03: Roadmap

Parts of the Computer System Hardware Software Data User

The Information Processing Cycle Essential Computer Hardware

Processing Devices Memory Devices Input Devices

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Parts of the Computer System

Computer systems have four parts Hardware Software Data User

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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

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Data Pieces of information Computer organize and present data

Users People operating the computer Most important part Tell the computer what to do

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Information Processing Cycle

Steps followed to process data Input Processing Output Storage

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Information Processing CycleInformation Processing Cycle

Essential Computer Hardware

Computers use the same basic hardware Hardware categorized into four types Input devices Processing devices Memory devices Storage devices

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Computer HardwareComputer HardwareComputer HardwareComputer Hardware

Mother BoardMother Board

Cont.

MotherBoard also called System Board Adaopter cards, process Chips, Memory

Chips. Small chips of silicon Circuits are attached on chips. Circuits have microscopic path for current

flow. Transistors and capcitors. Transistors open and close for electricity

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Input devices Allows the user to interact Input devices accept data

Keyboard, mouse

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The Keyboard

The most common input device Must be proficient with keyboard Skill is called keyboarding

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The Keyboard

How keyboard works Keyboard controller detects a key press Controller sends a code to the CPU

Code represents the key pressed Controller notifies the operating system Operating system responds Controller repeats the letter if held

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The Mouse

All modern computers have a variant Allows users to select objects

Pointer moved by the mouse

Mechanical mouse Rubber ball determines direction and speed The ball often requires cleaning

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The Mouse

Optical mouse Light shown onto mouse pad Reflection determines speed and direction Requires little maintenance

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The Mouse

Interacting with a mouse Actions involve pointing to an object Clicking selects the object Clicking and holding drags the object Releasing an object is a drop Right clicking activates the shortcut menu Modern mice include a scroll wheel

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The Mouse

Benefits Pointer positioning is fast Menu interaction is easy Users can draw electronically

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The Mouse

Mouse button configuration Configured for a right-handed user

Can be reconfigured Between 1 and 6 buttons Extra buttons are configurable

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Variants of the Mouse

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Trackballs Upside down mouse Hand rests on the ball User moves the ball Uses little desk space

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Track pads Stationary pointing

device Small plastic rectangle Finger moves across

the pad Pointer moves with the

pointer Popular on laptops

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Track point Little joystick on the keyboard Move pointer by moving the joystick

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Devices for the Hand

Pen based input Tablet PCs, PDA Pen used to

write data Pen used as

a pointer Handwriting

recognition On screen keyboard

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Devices for the hand

Touch screens Sensors determine

where finger points Sensors create an X,Y

coordinate Usually presents a

menu to users Found in cramped or

dirty environments

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Devices for the hand

Game controllers Enhances gaming experience Provide custom input to the game Modern controllers offer feedback Joystick Game pad

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Optical Input Devices

Allows the computer to see input Bar code readers

Converts bar codes to numbers UPC code

Computer find number in a database Works by reflecting light

Amount of reflected light indicates number

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Optical Input Devices

Image scanners Converts printed media into electronic Reflects light off of the image Sensors read the intensity Filters determine color depths

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Optical input devices

Optical character recognition (OCR) Converts scanned text into editable text Each letter is scanned Letters are compared to known letters Best match is entered into document Rarely 100% accurate

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Audiovisual Input Devices

Microphones Used to record speech Speech recognition

“Understands” human speech Allows dictation or control of computer Matches spoken sound to known phonemes Enters best match into document

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Musical Instrument Digital Interface MIDI Connects musical instruments to computer Digital recording or playback of music Musicians can produce professional results

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Digital cameras Captures images electronically No film is needed Image is stored as a JPG file Memory cards store the images Used in a variety of professions

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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

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Processing DevicesProcessing Devices

Cont.

Processors have two main parts

1.Control Unit

Interpret each instruction and take appropriate action

Traffic Control

1.Arithmetic logical unit

Perform arithmetic operation

And comparison too.

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Cont.

Registers

High speed storage

Temporary hold data

Different registers hold specific data

e.g Store fetching detail from where ALU performs computation

Sytem Clock

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Cont.

Heat Sinks:

Small ceramic or metal absorbs heat and disperse heat.

Heat Pipes:

Heat sinks consume more space

Liquid Cooling:

Flow of liquid that transfer heat fluid radiator type grill which cools the liquid and return to processor.

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Cont.

Parallel processing. Memory

Voltaile memory: loss contents

Non-Voltaile memory

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Memory devices Stores data or programs Random Access Memory (RAM)

main memory 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

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Memory DevicesMemory Devices

RAM: Volatile MemoryRAM: Volatile Memory RAM: Non-Volatile MemoryRAM: Non-Volatile Memory

Cont.

Types of RAM:

• DRAM: Chips need to be re-energized.

i. SDRAM: faster, use system clock

ii.DDR SDRAM: transfer twice data for each clock.

iii.Rambus DRAM: use rambus channel, pipelining, parallel channels.

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Cont.

SRAM: need not to be re-energize, use transistors instead of capacitors.

Cache uses SRAM technology. Megnatoresistive RAM(MRAM):

Use magnetic pattern than electric charges.

More capacity, faster, consume less power.

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Cont.

Types of ROM:

Data can not be modify.

PROM: data is microcode

EEPROM:

Erase micocode by electrical signals.

Cache:

L1 cache: on processor. Stores 8KB to 128KB.

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L2 Cache:

On processor.

64KB to 16 MB

L3 cache: on moterboard.

2MB to 6MB

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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

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Storage DevicesStorage Devices

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DRAM

Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within anintegrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory

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Education

Parts of the Computer System