Describe the general organization and architecture of computers. Identify computers’ major components and study their functions. Identify the various.

Introduction to Computer Organization and

Architecture

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Describe the general organization and architecture of computers.

Identify computers’ major components and study their functions.

Identify the various I/O peripherals and storage devices.

Lecture Objectives

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What is a Computer?

A computer is an electronic device that stores, accepts data, retrieves data, processes data and gives output according to a set of instructions.

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Hardware Physical components

Software Computer instructions

User Human operator

Elements of a computer

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Main Hardware Components

Input

Device

CPU Output

Device

Backing

Store

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This is the equipment that make up a computer system (physical components).

Many of these parts are contained within the computer’s case.

Other parts are connected to the computer (peripheral devices). These allow data to be entered (input) and retrieved (output) and stored

Hardware

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Input devices (mouse and keyboard) let the user enter data

Processing devices (processor)Output devices (monitor, speakers and printer) display data

Storage devices (memory sticks and disks) hold data

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Computer components

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The part of the computer performs the bulk of data processing operations is called the central processing unit

“Brain” as well as “heart” of computer system

The chip or chips at the heart of a computer that enable it to process data.

Central Processing Unit

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The CPU is made up of four major parts:

◦ Register set◦ ALU◦ Control units◦ Main memory

Memory: An area within a computer system that holds data waiting to be processed.

CPU Components

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Control unit◦ Control unit: supervises the transfer of

information among the registers and instructs the ALU as to which operation to perform by generating control signals.

Arithmetic logic unit (ALU)◦ Performs computation and comparison operations

Set of registers◦ Storage locations that hold inputs and outputs for

the ALU◦ Stores intermediate data during the execution of

instructions;

Components of the CPU

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Primary functions

◦ Hold data for currently executing program that is needed quickly or frequently (general-purpose registers)

◦ Store information about currently executing program and about status of CPU (special-purpose registers)

CPU Registers

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Input is any data entered into the computer’s memory.

input devices : the devices that allow data and instructions to enter a computer (such as a keyboard, mouse, scanner)

Input Devices

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Types of input include:◦ Data – Unorganized information (words,

numbers, images, or sounds) that the computer converts to meaningful information

◦ Software – Programs transferred from storage devices to the computer’s memory

◦ Commands – Instructions that tell the computer what to do

◦ Responses – Prompts requiring user feedback

Input Devices

Input device is any device that is used to transfer data into a computer so that it may be processed or stored permanently.

Each type of input device has an INTERFACE i.e a means of communication between the human user and the electronic computer

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Definitions

Data may be keyed in from source documents by keyboard operators

Computer Keyboard

Numeric keypad

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Modern data capture Methods

The source documents may be read directly by a document reader. Document readers capture information in the form of pictures or text already printed on paper.

Image ScannersOptical Character reader (OCR)Optical Mark reader (OMR)Magnetic ink character reader (MICR)Bar code readers

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Modern data capture Methods c.t.d.

Data may be captured directly without the need for any source document

Magnetic strip on a plastic card,

Smart card

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Modern data capture Methods ctd

Graphic input devices may be used to translate drawings or photographs into digital form that can be processed by a computer

MouseTrack ballTouch screenDigitizing tabletLight pen

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Modern data capture Methods ctd

A microphone can be attached to a sound card to provide audio input and also to issue commands and crate files

Speech recognition is a type of input in which the computer recognizes words spoken into a microphone.

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Sound Input

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Output devices are peripheral devices that enable us to view or hear the computer’s processed data. E.g. a display screen or printer)

Output: The product of the transformation of inputs by a process.

Output Devices

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Types of output

◦ Visual output – Text, graphics, and video

◦ Audio output – Sounds, music, and synthesized speech

Output Devices

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A monitor is a peripheral device which displays computer output on a screen.

Screen output is referred to as soft copy.

Types of monitors:

◦ Cathode-ray tube (CRT)

◦ Liquid Crystal Display (LCD or flat-panel)

Monitors

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A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.

Printers

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Laser printer works like a copier Quality determined by dots per inch (dpi)

produced Color printers available Expensive initial costs but cheaper to operate per

page

Types of PrintersLaser

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Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper

Letter-quality printouts Cost of printer is inexpensive but ink is costly

Types of Printers ctdInkjet

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A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.

It is used in engineering, drafting, map making, and seismology.

Plotter

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Audio output is the ability of the computer to output sound.

Two components are needed:◦ Sound card – Plays contents of digitized recordings

◦ Speakers – Attach to sound card

Audio Output: Sound Cards and Speakers

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Storage device: ◦ The place where a computer puts data. ◦ The area within a computer system where data

can be left on a longer term basis while it is not needed for processing.

Computer Sorage

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Storage devices:◦Retain data when the computer is turned off

◦Are cheaper than memory

◦Play an important role during startup

◦Are needed for output

Why Is Storage Necessary?

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Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material

Optical – Storage devices that use laser beams to read patterns etched into plastic disks

Storage Technologies: Magnetic and Optical

Magnetic Storage Optical Storage – CD/DVD drive

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CD-ROM stands for Compact Disc-Read Only Memory.

CD-ROM drives can not write data to discs.

They are capable of storing 650 MB of data.

They are used for storing operating systems, large application programs, and multimedia programs.

CD-ROM Discs and Drives

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CD-R Discs can be read and written to Discs can only be written to “once” CD-R drives are capable of reading and

writing data

CD-R and CD-RW Discs and Recorders

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CD-RW Discs can be read and written to Discs are erasable Discs can be written to many times CD-RW drives are capable of reading,

writing, and erasing data

CD-R and CD-RW Discs and Recorders

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DVD stands for Digital Video Disc.

DVD technology is similar to CD-ROM technology.

DVDs are capable of storing up to 17GB of data.

The data transfer rate of DVD drives is comparable to that of hard disk drives.

DVD-R and DVD-RW drives have the ability to read/write data.

DVD-ROM Discs and Drives

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Solid state storage devices use nonvolatile memory chips to retain data.

They do not have moving parts.

They are small, lightweight, reliable, and portable.

Solid State Storage Devices

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Solid State Storage Devices

Flash Memory

Smart Card

PC Card

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Solid State Storage Devices

Compact Flash Memory

Micro Drive

Memory Stick

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