Hardware. Basic Computer System Central Processing Unit Input Devices Output Devices Backing Storage Devices

HardwareHardware

Basic Computer SystemBasic Computer System

CentralProcessingUnit

InputDevices

OutputDevices

BackingStorageDevices

Basic Computer SystemBasic Computer System

ProcessorProcessor– to process datato process data

MemoryMemory– RAM stores programs and data RAM stores programs and data when in usewhen in use – ROM stores essential programs and data ROM stores essential programs and data permanentlypermanently

Input devicesInput devices– a way of getting data into the computera way of getting data into the computer

Output devicesOutput devices– so the computer can show us what it has doneso the computer can show us what it has done

Backing storage devicesBacking storage devices– to store programs and data when not in useto store programs and data when not in use

Central Processing UnitCentral Processing Unit

Central Processing Unit

Input DeviceOutput Device

Backing Storage

memory

processor

MemoryMemory


Memory

Processor

RAM ROM

RAM is random access memory

RAM memory is used to store the programs being run and the files being used. RAM memory is lost when power is switched off.

ROM is read only memory

ROM memory is fixed memory which is placed there by the manufacturer and is used to store programs which are involved in the running of the computer system.

ROM memory is not lost when power is switched off.

MemoryMemoryThe memory is split up into memory locations which store the data. Each memory location is like a pigeon hole where the data will be stored as bits. Each memory location has its own memory address.

The number of bits stored in each memory location is called the memory word size. This can be 16, 24 or 32 bits.

This is also the number of bits that are transferred at a time between the memory and the processor.

Processor

Memory


ProcessorProcessorThe processor has 3 parts

ALUThe Arithmetic And Logic Unit, as its name suggests carries out the calculations and decision making

Control UnitThe Control Unit is in charge of the flow of data and the order and timing of processing instructions

RegistersRegisters are temporary memory locations within the processor which hold data and information while it is being processed.

Processor

Memory


ALU

Control Unit

Registers

Central Processing UnitCentral Processing Unit


Processor

Memory

ALU

Control Unit

Registers

RAM ROM

Input DevicesInput Devices

Computers are digital devices which Computers are digital devices which work with numbers - work with numbers - binarybinary numbersnumbers..

All information used by a computer is All information used by a computer is held as a pattern of held as a pattern of onesones and and zeroszeros..

Input devices are used to change Input devices are used to change information we understand into data information we understand into data the computer can process - binary the computer can process - binary numbers.numbers.

Input Input KeyBoard KeyBoard

InputInput Keyboard Keyboard

InputInput Concept Keyboard Concept Keyboard

InputInput Mouse Mouse

InputInput Touch Pad Touch Pad

InputInput Tracker Ball Tracker Ball

InputInput Joystick Joystick

InputInput Devices Devices

KeyboardKeyboard Concept KeyboardConcept Keyboard MouseMouse Touch PadTouch Pad Tracker BallTracker Ball JoystickJoystick

InputInput Graphics Tablet Graphics Tablet

InputInput Touch Sensitive Touch Sensitive ScreenScreen

InputInput Touch Screen Touch Screen

InputInput Digital Camera Digital Camera

InputInput Digital Video Digital Video CameraCamera

InputInput Web Camera Web Camera

InputInput Microphone Microphone

InputInput Sound Card Sound Card

InputInput Scanner Scanner

InputInput Hand Held Scanner Hand Held Scanner


Graphics TabletGraphics Tablet Touch Sensitive ScreenTouch Sensitive Screen Digital CameraDigital Camera MicrophoneMicrophone Sound CardSound Card ScannerScanner

InputInput Bar Code Bar Code

InputInput OMR OMR

InputInput OCR OCR

InputInput MICR MICR

InputInput Punched Card Punched Card

Input Input Punched TapePunched Tape

InputInput Magnetic Stripe Magnetic Stripe


Bar Code ReaderBar Code Reader Optical Mark ReaderOptical Mark Reader Optical Character ReaderOptical Character Reader Magnetic Ink Character ReaderMagnetic Ink Character Reader Punched Card ReaderPunched Card Reader Punched Tape ReaderPunched Tape Reader Magnetic Stripe ReaderMagnetic Stripe Reader

Output DevicesOutput Devices

Computers are digital devices which Computers are digital devices which work with numbers - work with numbers - binary numbersbinary numbers..


Output devices are used to change Output devices are used to change data the computer has processed - data the computer has processed - binary numbers into information we binary numbers into information we can understand.can understand.

OutputOutput Monitor Monitor

OutputOutput Cathode Ray Cathode Ray TubeTube

OutputOutput Liquid Crystal Liquid Crystal DisplayDisplay

OutputOutput Thin Film Thin Film TransistorTransistor

OutputOutput Graphics Card Graphics Card

OutputOutput Ink Jet Printer Ink Jet Printer

OutputOutput Ink Jet Printer Ink Jet Printer

OutputOutput Laser Printer Laser Printer

OutputOutput Laser Printer Laser Printer

OutputOutput Drum Plotter Drum Plotter

OutputOutput Flat Bed Plotter Flat Bed Plotter

OutputOutput Sound Card Sound Card

OutputOutput Speakers Speakers

OutputOutput Headphones Headphones

OutputOutput Robot Arm Robot Arm

OutputOutput Devices Devices

MonitorMonitor– CRT cathode ray tubeCRT cathode ray tube– LCD liquid crystal displayLCD liquid crystal display– TFT thin film transistorTFT thin film transistor

Graphics CardGraphics Card PrinterPrinter

– Ink Jet PrinterInk Jet Printer– Laser PrinterLaser Printer

PlotterPlotter– DrumDrum– Flat bedFlat bed

OutputOutput Devices Devices

Sound CardSound Card SpeakersSpeakers HeadphonesHeadphones Robot ArmRobot Arm

Backing Storage DevicesBacking Storage Devices

Computers are digital devices which Computers are digital devices which work with numbers - work with numbers - binary numbersbinary numbers..


Backing storage devices are used to Backing storage devices are used to permanently storepermanently store computer data - computer data - binary numbers.binary numbers.

Backing Storage UnitsBacking Storage Units

BitBit (binary digit)(binary digit) 1 or 01 or 0 ByteByte (by eight) (by eight) 8 bits8 bits KilobyteKilobyte (Kb) (Kb) 1024 bytes1024 bytes

almost a thousand bytesalmost a thousand bytes

MegabyteMegabyte (Mb) (Mb) 1024 kilobytes1024 kilobytesalmost a million bytesalmost a million bytes

GigabyteGigabyte (Gb) (Gb) 1024 megabytes1024 megabytesalmost a thousand, million bytesalmost a thousand, million bytes

TerabyteTerabyte (Tb) (Tb) 1024 gigabytes1024 gigabytesalmost a million, million bytesalmost a million, million bytes

Backing Storage UnitsBacking Storage Units

10x10X10X10 = 1010x10X10X10 = 1044 = 10000 = 10000 This is a nice This is a nice roundround number in number in decimaldecimal.. It is easy for us to work with.It is easy for us to work with.

2x2x2x2x2x2x2x2x2x2= 22x2x2x2x2x2x2x2x2x2= 21010 = 1024 = 1024 This is a nice This is a nice roundround number in number in binarybinary.. It is easy to arrange in a computer It is easy to arrange in a computer

system.system.

Bits and BytesBits and Bytes

We use binary to store:We use binary to store:NumbersNumbersTextTextGraphicsGraphicsVideoVideoSoundSoundProgramsPrograms

Storing NumbersStoring Numbers

NumbersNumbers are converted to in binary. are converted to in binary.

11Bin Bin is is 11DecDec

1010Bin Bin isis 22DecDec

10001000Bin Bin is is 88DecDec

10011001Bin Bin isis 99DecDec

11111111BinBin isis 1515DecDec

1111111111111111BinBin isis 255255DecDec

Binary to DecimalBinary to Decimal

BinaryBinary DecimalDecimal

128 64 32 16 8 4 2 1128 64 32 16 8 4 2 1

0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 000 0 0 0 0 0 0 10 0 0 0 0 0 0 1 110 0 0 0 0 0 1 00 0 0 0 0 0 1 0 220 0 0 0 0 0 1 10 0 0 0 0 0 1 1 330 0 0 0 0 1 0 00 0 0 0 0 1 0 0 440 0 0 0 0 1 0 10 0 0 0 0 1 0 1 550 0 0 0 0 1 1 00 0 0 0 0 1 1 0 660 0 0 0 0 1 1 10 0 0 0 0 1 1 1 77

IntegersIntegers

These are whole numbers which have These are whole numbers which have no decimal part. no decimal part.

They can be easily converted to binary They can be easily converted to binary numbers.numbers.

1 byte can only store numbers up to 1 byte can only store numbers up to 255.255.

The computer can perform calculations The computer can perform calculations on integers very quickly and on integers very quickly and efficiently.efficiently.

Storing TextStoring Text

Text is stored using a special set of codes called Text is stored using a special set of codes called ASCII.ASCII.

AAmerican merican SStandard tandard CCode for ode for IInformation nformation IInterchangenterchange

Each symbol (letter, number etc) has its own Each symbol (letter, number etc) has its own unique codeunique code

aa is 97, is 97, AA is 65, is 65, ?? is 63, is 63, 33 is 51 is 51

One ASCII code is one byte long (eight bits).One ASCII code is one byte long (eight bits).

Storing GraphicsStoring Graphics

Black and White graphics are stored Black and White graphics are stored using pixels (using pixels (Picture ElementsPicture Elements).).

The image to be stored is broken up The image to be stored is broken up into dots, each dot is a pixel.into dots, each dot is a pixel.

The pixels are 1 for black and 0 for The pixels are 1 for black and 0 for white.white.

Calculating Image Calculating Image StorageStorage

A black and white graphic uses 1 bit to store A black and white graphic uses 1 bit to store each pixeleach pixel

If the image is 300 pixels by 200 pixels then it is If the image is 300 pixels by 200 pixels then it is stored using a total of stored using a total of 300 x 200 bits300 x 200 bits i.e. 60000 i.e. 60000 bitsbits

Divide this by 8Divide this by 8 to give the number of bytes to give the number of bytes– 60000/8 = 750060000/8 = 7500

Divide this by 1024Divide this by 1024 to give the number of to give the number of kilobyteskilobytes– 7500/1024 = 7.3247500/1024 = 7.324

Round upRound up to ensure you have enough storage to ensure you have enough storage– 7.324 = 8 Kb7.324 = 8 Kb

StorageStorage Floppy Disc Floppy Disc



StorageStorage Magnetic Disc Magnetic Disc

StorageStorage Magnetic Disc Magnetic Disc

StorageStorage Magnetic Tape Magnetic Tape



StorageStorage Smart Card Smart Card

StorageStorage CD ROM CD ROM

StorageStorage CD ROM CD ROM

StorageStorage DVD DVD

StorageStorage USB Flash Drive USB Flash Drive

Backing StorageBacking Storage Devices Devices

Floppy DiscFloppy Disc 1.44Mb1.44Mb Magnetic DiscMagnetic Disc SeveralSeveral GbGb Magnetic TapeMagnetic Tape SeveralSeveral GbGb Smart Card Smart Card few Kbfew Kb Compact Disc Compact Disc 650 Mb650 Mb

– CD ROM CD R CD RWCD ROM CD R CD RW Digital Versatile Disc Digital Versatile Disc 4.2 Gb – 17 Gb4.2 Gb – 17 Gb

– DVD ROM DVD R DVD RW DVD RAMDVD ROM DVD R DVD RW DVD RAM USB Flash DriveUSB Flash Drive 16 – 256 Mb16 – 256 Mb

Backing StorageBacking Storage Devices Devices

MagneticMagnetic– Floppy DiscFloppy Disc– Hard DiscHard Disc– TapeTape

OpticalOptical– CDROM CDR CDRWCDROM CDR CDRW– DVD DVD R DVD RW DVD RAMDVD DVD R DVD RW DVD RAM

FlashFlash– USB drivesUSB drives

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Hardware. Basic Computer System Central Processing Unit Input Devices Output Devices Backing Storage Devices