Computers, Hardware, Operating Systems and Software Lecture 3

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Computers, Hardware, Operating Systems and
Software Lecture 3
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Introduction

• A computer system consists of
• hardware
• system programs
• application programs

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Computer Hardware
Bus

• Input Devices
• Central Processing Unit
• Output devices

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Input Devices

• Action based input devices
• Keyboard
• Mouse
• Light pen
• Touch screen
• Non-action based input devices
• Optical character recognition
• Magnetic ink
• Voice input
• Image scanners
• Graphics tablets

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Central processing units

• Measurements
• Coding schemes
• Clock speed
• Random access memory (RAM)
• Storage
• Media
• Access of secondary storage
• Disk devices
• Floppy disks
• Hard disks
• Optical disks
• Magnetic tape
• Peripherals
• Network cards
• Video Cards
• Modems

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Output devices

• Display devices
• Terminals
• Monitors
• Printers
• Other output devices
• Plotters
• Voice output device
• Film recorder
• Microfiche

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Software

• Collections of instructions to the computer
  hardware
• Operating systems
• Off the shelf applications
• Bespoke applications
• Utilities
• Programming tools

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What is an Operating System

• A number of software tools to allow
• Communication between the user and the computer
• Control of the processor and the storage hardware
• Management of files
• Use of peripherals like printers and modems
• Can be command driven or have a graphic user
  interface

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Desktop Operating Systems

• Dos
• Windows
• Apple
• Unix
• OS2

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Network Operating Systems

• Windows NT/2000
• Unix
• Novell
• VMS

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Off the Shelf Software Packages

• Office Suites
• Word Processing
• Spreadsheets
• Databases
• Graphics

• Communications
• E-Mail
• FTP
• X Session

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Software Packages

• Specialist Applications
• Accounting
• CAD / CAM

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Modified Software

• Macro Languages
• Visual Basic for Office
• Lotusscript

• Reporting Tools
• Open Database Connectivity (ODBC)
• Crystal Reports

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Bespoke Software

• Custom software for specific applications
• Precise fit to organisations information
  requirements
• Organisation controls data structures and input
  screens
• Can be integrated with other systems
• Can be modified to adapt to changing needs

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Utilities

• Anti virus
• File management and recovery
• Memory management

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Programming Tools

• Programming languages
• Visual Basic
• C
• Java
• Compilers and assemblers
• Computer Aided Software Engineering (CASE)