Input Output Devices and Memory Unit

Input Output Devices

And MEMORY UNIT

Input Unit• The input unit is responsible for

accepting input i.e., Data and instruction from the user

3

Keyboard

Keyboard - device that has keys that enables one to type text and issue commands to the computer.

4

Mouse

Mouse - device that points and selects text or icons.

MOUSE WAS INVENTED BY DOUGLAS ENGELBART IN 1963

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SCANNER

SCANNER-A scanner is device like photocopier, which creates an electronic form of printed images

.

Some more input devices

• JOYSTICK-used for playing games on computer.

• Microphone(Mic)-used to input sound.

• OCR(OPTICAL CHARACTER READER)• MICR(MAGNETIC INK CHARACTER READER)• BAR CODE READER

Processing UnitProcessing unit or

Central Processing Unit is responsible for carrying out the processing job.

The CPU is the brain of computer i.e., the place where data is manipulated

Components of CPUA CPU has 2 components1. ALU(Arithmetic Logic Unit)- The ALU performs

Arithmetic(+,-,*,/ etc) and Logic (>,<,>=,<=,=,<>) operations.

2. CU(Control unit)-It controls the entire Processing.

Basic Organization of a Computer

Output UnitThe output unit is responsible for

producing the output in user readable form.

The function of output device is to present processed data to the user

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MonitorMonitor - The box that

contains the screen where images and text are displayed.

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PrinterPrinter - device that

allows one to print text and pictures.

13

SpeakersSpeakers - device that

allow you to hear voice, music, and other sounds from your computer.

Memory Unit• This unit is responsible for

providing the space for storing data.

• The area where computer store something temporary or permanently is called memory.

• Hardware that allows you to store or retrieve information

Units of MemoryNibble Group of 4 bitsByte Group of 8 bitsKilo Byte 1 KB = 1024 BytesMega Byte 1 MB = 1024 KBGiga Byte 1 GB= 1024 MBTera Byte 1 TB = 1024 GBPeta Byte 1 PB = 1024 TB

NOTE : 1024 = 210

Memory

Memory

Primary Memory / Internal Memory / Main Memory

Secondary Memory/ External Memory / Permanent Memory /

Auxiliary Memory

Broadly memory can classified into two types

1.) Primary memory(Main Memory)2.) Secondary Memory

Difference between primary and secondary memory

• Primary Memory :- It has a very fast access to time and smaller storage capacity.

• Secondary Memory :- It has slow access time and large storage capacity. It is called user’s memory.

Primary Memory

Primary Memory

RAM(Random Access Memory)

ROM(Read Only Memory)

Primary Memory Holds the data and programs needed at the instant by CPUPrimary memory can further be classified into 2 types1.) RAM(Random Access Memory)2.)ROM(Read Only Memory)

RAM(Random Access

Memory) It is called random access memory It has random access property. It has limited storage capacity. It is volatile in nature means its

contents get removed when power supply is switched off.

ROM(Read Only Memory)

It is Read only memory. It cannot be used for user

programs. It holds booting instructions. It is non – volatile in nature it

means its contents remain stored when power supply is switched off.

Secondary Memory

Secondary Memory

Hard Disk CD DVD

Since Primary has limited storage capacity and is not permanentSecondary Storage Devices are used to store Large amount of Data Permanently.Some most common Storage Devices are mentioned Below

Hard DiskHard Disk-Used

to store data inside of the

computer

CD-Compact DiskCD’s can store 650MB to 800MB of

information and data.Types OF CD• CD-ROM(Compact Disk-Read Only

Memory)• CD-R(Compact Disk Recordable)• CD-(RW)Compact Disk Rewritable)

DVD-Digital Video DiskDVD can store 4.8GB to 8.0GB of

information and data.Types OF DVD• DVD-ROM (DVD-Read Only

Memory)• DVD-R (DVD Recordable)• DVD-RW (DVD Rewritable)

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