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AS LEVEL ICT – MODULE 2

AS LEVEL ICT – MODULE 2. Revision Slides. Introduction to Computer Systems. Components of a computer Input & Output devices Processor Memory Storage ASCII. Data Capture. Keyboard entry Voices entry Key to disk systems Mouse, joystick, light pen & touch screen MICR Smart Cards

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AS LEVEL ICT – MODULE 2

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  1. AS LEVEL ICT – MODULE 2 Revision Slides

  2. Introduction to Computer Systems • Components of a computer • Input & Output devices • Processor • Memory • Storage • ASCII

  3. Data Capture • Keyboard entry • Voices entry • Key to disk systems • Mouse, joystick, light pen & touch screen • MICR • Smart Cards • Magnetic Stripe • Bar Codes

  4. Data Capture Types of error Batch processing Validation checks Presence Check Format check Check Digit Range check File lookup check Verification Detecting transmission errors Accuracy and validity Validation & Verification

  5. What is a database Retrieving information from a database Flat files Problems with flat files Redundant data Errors on input Problems with modifying data Problems with updating data Introduction to Databases

  6. Relational Databases • Using multiple tables • Putting data in correct tables • Significance of field types • Primary Key

  7. Tables, Forms, Queries & Reports • Tables • Forms • Queries • Reports • Selecting a suitable output format

  8. Systems Software • What is an operating system • Functions of an operating system • Utility programs • The DOS operating system • Command-driven interface • Graphical user interface • DOS / Windows / UNIX / LINUX

  9. Categories of Software • Systems software • Applications software • General purpose software • Integrated packages • Generic & specific software

  10. Generic Software • Word Processing • Spreadsheets • Databases • Electronic Mail • Presentation Graphics • Application generators • Report generators • Web browsers

  11. Capabilities of Software • Object linking & embedding • The need for portability of data • Problems with portability • Upgradability • Criteria for selecting a software package • Evaluating software • Software reliability

  12. Modes of Processing • Transactions • Master & transaction files • Batch processing • Interactive processing • Real time & pseudo real time processing • Criteria for choice of processing mode

  13. Processing Different Types of Data • Representing numbers • Real numbers • Digitised sound • MIDI • Bit-mapped graphics • Vector graphics

  14. Primary & secondary sources File processing concepts Floppy & ZIP disks How data is stored Hard disks Magnetic tape CD ROM WORM disks Magneto-optical disks Microfiche Storage Devices

  15. Issues of privacy Threats of information systems Data Integrity Standard clerical procedures Write-protecting disks User ID’s & passwords Access rights Securing against fraudulent use Protection against viruses Biometrics Communications security Disaster Planning Security of Data

  16. Backup • Periodic backup • Backup strategies • Backup hardware • Backing up on line databases • Factors in a backup strategy • Recovery procedures

  17. Printers Dot Matrix Ink jet Laser Plotters VDU Communicating with the CPU Parallel & serial transmission Buffering Spooling Installing hardware devices Output Devices

  18. Advantages & disadvantages of LANs Server vs. Peer to peer networks Wide Area Networks Communications links Communications media ISDN lines Bridges & gateways Modems Synchronous and asynchronous transmission Protocol Factors affecting transmission speed Network Environments

  19. Importance of good interface design Designing usable systems Interface styles Command line interface Menus Natural Language Forms & dialogue boxes WIMP interface Advantaged of a command user interface Speech input Speech / sound output User Interfaces

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