2. Standard Grade Computing OPERATING SYSTEMS CHAPTER 20

3. Standard Grade Computing SYSTEM SOFTWARE System software is a collection of programs which help the computer to work properly. It includes the Operating system Filing system Translator programs Foundation

4. Standard Grade Computing OPERATING SYSTEM (OS) An OS is a program that controls how the computer works e.g. Windows XP. It will Check input devices e.g. keyboard Send data to output devices e.g. printer Control data flow to/from main memory Manage the filing system Control system security Provide the HCI e.g. WIMP Report any errors Foundation

5. Standard Grade Computing DIRECTORY / FOLDER An area where files are stored is called a directory or a folder. Each folder may contain other folders or documents Foundation

6. Standard Grade Computing TYPES OF SYSTEM Interactive System Allows the user & computer to communicate. Computer responds directly to commands e.g. word processing, a computer game. Real – time System A system which responds immediately to input e.g. online booking system. General

7. Standard Grade Computing TYPES of FILE PROGRAM Contains the instructions of how to do a tasks e.g. payroll program for a large company. DATA Used by the program when it is running e.g. employee wage details – basic pay, overtime etc General

8. Standard Grade Computing OPERATING SYSTEMS File Management Deals with how files are stored on backing storage – save and load Credit Memory Management Controls where programs & data are placed in main memory Error Reporting Computer tells the user about any mistakes made.

9. Standard Grade Computing Device Drivers A program added on to the OS which allows the computer to communicate with that device e.g. scanner driver allows computer to read data from the scanner UTILITIES Background Job A job which runs in the computer system as the user interacts with another program e.g. print job. Credit

10. Standard Grade Computing Human Computer Interface Command Driven Enter command for computer to follow e.g. a Visual Basic program Menu Driven Select functions from a menu WIMP (G raphical U ser I nterface ) WINDOW ICON MENU POINTERS Credit

11. Standard Grade Computing DATA ACCESS Sequential Access Data put into order then stored on tape. It is read in the same order that it was stored. Good as a backup but slow data access. Random/Direct Access Data can be found straight away. Good for day to day use as fast, direct access to data. Credit

12. Standard Grade Computing HIERARCHICAL FILING SYSTEM Credit Main/Root Directory & Sub-directories Directories and Sub-directories

13. Standard Grade Computing And there is more…. Can you wait for the next exciting chapter?