Computer HardwareComputer Software

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InputDevices

SecondaryStorage

PrimaryStorage

Computer Components

CPU

OutputDevices

CommunicationsDevices

Buses

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How Computers Represent Data Bit

– Binary Digit. On/off, 0/1, Magnetic/not

Byte– Group of Bits for One Character

• EBCDIC- Extended Binary Coded Decimal Interchange Code (8 or 9 Bits Per Byte)

• ASCII- American Standard Code for Information Exchange (7 or 8 Bits Per Byte)

Parity Bit– Extra Bit Added to Each Byte to Help Detect

Errors

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Examples Of Bytes

C: 1100 0011 0 100 0011 1

A: 1100 0001 1 100 0001 0

T: 1110 0011 1 101 0100 1

Note how sum for each byte is an EVEN number

EBCDIC ASCII (assume even-parity system)

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CPU - Central Processing Unit

It is the Heart of the Computer. A Collection Of Electronic Circuits. Electronic Impulses Enter The CPU From

An Input Device. These Impulses Are Sent Under Program

Control Through Circuits To Create A Series Of New Impulses.

A Set Of Impulses Leaves The CPU For The Output Device.

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Two CPU Sections

Arithmetic/Logic Unit (ALU) - Performs Arithmetic And Logical Operations On Data.– Arithmetic Operations: + - * /

– Logical Operations: Comparing Data

Control Unit - Section Of The CPU That Directs The Flow Of Electronic Traffic Between:– Memory And The ALU

– CPU and Input And Output Devices

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Memory

Primary (Internal) Storage Holds:– Programs And Data Passed To The Computer

For Processing– Intermediate Processing Results– Output That Is Ready To Be Transmitted To

Secondary Storage Or To An Output Device.

Eg: RAM

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Memory Address

Once Programs, Data, Intermediate Results, And Output Are Stored In Memory, The CPU Must Be Able To Find Them Again.

Each Location In Memory Has An Address.

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Memory Size

Kilobyte (KB): 210 Bytes... 1024 Bytes

Megabyte (MB): 210 KB... “Million” Bytes

Gigabyte (GB): 210 MB... “Billion” Bytes

Terabyte (TB): 210 GB... “Trillion” Bytes

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Registers

A High Speed Staging Area Within The Computer That Temporarily Stores Data During Processing.

These Areas Called Registers. Part Of The CPU

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Four Types Of Registers Instruction

Address

Storage

Accumulator

Holds The Part Of The Instruction Indicating What The Computer IsTo Do Next.

Contains The Memory LocationOf Data To Be Used.

Prior To Processing, The RegisterThat Temporarily Stores Data That Have Been Retrieved From Memory.

Stores The Result Of An ArithmeticOr Logical Operator.

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Types Of Memory

RAM : Random Access Memory– Dynamic: Changes Thru Processing– Static: Remains Constant (Power On)

ROM : Read Only Memory (preprogrammed)– PROM: Program Can Be Changed Once– EPROM: Erasable Thru Ultraviolet Light– EEPROM: Electrically Erasable

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How Devices Are Linked

BUS

CPU RAM ROMAdd-InBoards

I/ODevices

Ports

I/ODevices

BUS allows CPU to communicate with RAM,ROM, and peripheral devices connectedthrough either boardsor ports.

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Secondary Storage

Disk

Tape

Optical Storage

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Optical Storage

CD-ROM: 500-660 MEGABYTES– LAND: Flat parts of disk surface reflects light– PITS: small scratch on surface scatters light

WRITE ONCE / READ MANY (WORM):– CD-R: Compact Disk - Recordable– CD-RW: CD - Rewritable

DIGITAL VIDEO DISK (DVD): CD size, up to 10 gigabytes of data

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Input/Output Devices

Pointing Devices

Source Data Automation

Output Devices

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Pointing Devices

Keyboard Mouse

– Wired– Infra-red– Trackball– Touch Pad

Joystick Touch Screen

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Source Data Automation

Captures Data In Computer Form At Time & Place Of Transaction

Barcode– Identifies Products in Stores, Warehouses,

Shipments Magnetic Ink Character Recognition

(MICR)– Special Ink Identifies Bank, Account,

Amount

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Source Data Automation Pen-Based Input

– Digitizes Signature Digital Scanner

– Translates Images & Characters Into Digital Form Voice Input Devices

– Converts Spoken Word Into Digital Form Sensors

– Devices That Collect Data From Environment for Computer Input (E.G., Thermometers, Pressure Gauges)

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Output Devices

Cathode Ray Tube (CRT)

Printer

Plotter

Voice Output Device

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Data Processing

Batch Processing– Transaction Data Stored Until Convenient to

Process As a Group. Useful for Less Time-sensitive Actions.

On-line Processing– Transaction Data Entered Directly Into

System, Constantly Updating Files. Requires Direct-access Devices.

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Categories Of Computers

Supercomputer

Mainframe

Midrange & Minicomputer

Server

Personal Computer (PC)

Workstation

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Supercomputer

Highly Sophisticated

Complex Computations

FASTEST CPUs

Large Simulations

State-of-the-art Components

Expensive

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Mainframe

Largest Enterprise Computer

50 Megabytes to Over One Gigabyte RAM

Commercial, Scientific, Military Applications

Massive Data

Complicated Computations

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Midrange/Minicomputer

Middle-Range 10 Megabytes To Over One Gigabyte

RAM Universities, Factories, Labs Used As Front-End Processor For

Mainframe

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Client / Server

Networked Computers Client

– User (PC, Workstation, Laptop) Requires Data, Application, Communications It Does Not Have

Server– Component (Computer) Having Desired Data,

Application, Communications

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Client ServerRequests

Data, Service

User Interface

Application

Function

Data

Application Function

Network Resources

Client / Server

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Microcomputer

Desktop or Portable

64 Kilobytes to Over 128 Megabytes RAM

Personal or Business Computers

Affordable

Many Available Components

Can Be Networked

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Workstation

Desktop Computer

Powerful Graphics

Extensive Math Capabilities

Multi-tasking

Usually Configured To Special Function: e.g.; CAD, Engineering, Graphics

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Centralized / Distributed

Centralized– Processing By Central Computer Site

• One Standard

• Greater Control

Distributed– Processing By Several Computer Sites Linked

By Networks• More Flexibility

• Faster Response

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Sharing Computers

Network Computer– Simplified Desktop Computer Stores

Minimum Data to Function (Uses Server)

Peer-to-Peer Computing– Networked Computers Share Data, Disk

Space, Processing. Parallel Processing on a Smaller Scale

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Managing Hardware Assets

Understand Technology Requirements Determine Total Cost Of Ownership

– Hardware, Software, Installation, Training, Support, Maintenance, Infrastructure

Plan Capacity & Scalability Identify Trends

Computer Software

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Software Detailed Instructions To Control Computer

Operation Program

– Set Of Instructions To The Computer Stored

– Program Must Be In Primary Storage System Software

– Manages Computer Resources Application Software

– Specific Business Application

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Programming Languages:

Assembly Language; Fortran; Cobol; Pl / 1; QBasic; Pascal; C; C++; Fourth Generation Languages

Operating System:• Scheduled Computer

Events • Allocates Computer

Resources Monitors Events

Language Translators:• Interpreters• Compilers

Utility Programs:• Routine Operations

Manage Data

Hardware

System Software

Application Software

Software

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Language Translation

Source Code– High-level Language Instructions

Compiler– Translates High-level Code Into Machine

Language

Object Code– Translated Instructions Ready For Computer

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Graphical User Interface (GUI)

Operating System Uses Graphic Icons

– Icons, Buttons, Bars, Boxes

Pointer– Mouse, Pen, Touch Screen

To Issue Commands Make Selections

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32-bit operating system, GUI, multitasking, networking

32-bit operating system not limited to Intel chips. Multitasking, multiprocessing, networking

32-bit. Developed for IBM PS/2. Multitasking, networking

Paired-down for handheld computers, wireless communication devices

Windows 98 & 95

Windows NT Me & 2000

Windows CE

OS/2

Operating System Features

Microcomputer Operating Systems

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Mac OS For Macintosh computers. Multitasking. Powerful graphics, multimedia

Unix For powerful microcomputers, workstations, minicomputers. Multitasking, multi-user processing, networking. Portable to various computer platforms

DOS For IBM (PC-DOS) and PC (MS-DOS). Program memory: 640K

Linux Free, reliable alternative to Unix, Windows. Runs on many Platforms. Open-source

Microcomputer Operating Systems

Operating System Features

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Generations Of Programming Languages 1st. Since 1940s. Machine Language:

Binary Code

2nd. Since Early ’50s. Assembly Language: Mnemonics for Numeric Code

3rd. Since Mid ‘50s. High-level Languages

4th. Since Late ‘70s. Modern Application Packages

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High-Level Languages

FORTRAN (Formula Translator): Scientific, Engineering Applications

COBOL (Common Business Oriented Language): Predominant for Transaction Processing

BASIC (Beginners All-purpose Symbolic Instruction Code): General Purpose PC Language

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High-level Languages

PASCAL: Used to Teach Structured Programming Practices. Weak in File Handling, Input / Output

C and C++: Powerful PC Language for Developing Applications. Efficient Execution; Cross Platform. C++ Is Object Oriented

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Fourth Generation Languages (4GL) Can Be Employed By End Users

Nonprocedural

Can Develop Applications Quickly

Natural Languages

Six Categories

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Fourth Generation Languages (4GL)

Query Languages:– Rapidly Retrieve Data– Interactive/ On-line– May Use NATURAL LANGUAGE– Support Special Requests for Data From

Relational Databases

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Report Generators:– Create Customized Reports– Wide Range of Formats

Graphics Languages:– Can Manipulate Drawings, Graphs,

Photos, Videos– Presentation Managers

Fourth Generation Languages (4GL)

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Application Generators– User Specifies Computer Needs

– Generator Creates Logic and Code for Application

– Greatly Reduces Development Time

Very High-level Programming Languages– Professional Programmer Productivity Tool

– Uses Fewer Instructions

– Reduces Development Time

Fourth Generation Languages (4GL)

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Software Package: Commercially Available Set of Programs.– Word Processing– Spreadsheets– Data Management– Presentation Management

Integrated Software Package Now Combine These To Simplify Learning And Use

Fourth Generation Languages (4GL)

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Software Tools

Word Processing Spreadsheets Data Management Presentation Graphics Integrated Software Suites E-mail Web Browsers Groupware