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Operating Systems including File Management
By the end of this lesson you will be able to explain the terms: Operating Systems Functions of an operating system 3 types of processing. Hierarchical file management Device driver Background Job Foreground Job
What is an Operating System? An operating system is a piece of system software. The OS software is loaded the instant the computer is switched on. Operating Systems: 1. controls all pieces of hardware eg: main memory backing storage device eg hard disk CPU input devices output devices, and so on. 2. and provides the HCI. The OS is essential as without it the computer could do nothing.
Functions of OS 1. Memory Management 2. Provides the HCI (Human Computer Interface) 3. File Management 4. Controls Input/Output Devices 5. Job Scheduler Controls main memory storage of programs and data, enabling multi-programming. Moves data to and from main memory and backing storage devices. Organises data on backing store in a systematic way. Communicates with peripherals eg printers, monitors Accepts data from input devices eg keyboard, mouse Shares CPU time for multi-user system. Allocates resource time between all users. eg networked printers.
Pupil Tasks Answer the following questions in your jotter. 1. Explain when an operating system is loaded for use. 2. Explain what an operating system is. 3. List 2 tasks that an operating system performs. 4. Identify what OS is used in this school. 5. Explain the term multi-programming. 6. Explain the term multi-user. 7. Are our computers multi-user and/or multi-programming? Explain. 8. Can a computer be multi-user and multi-programming? Explain. 9. Why is an OS used when we ask for a printout? 10. Why is an OS used when we save a file?
Types of Processing of data can either be: Interactively Real-time Batch. Operating systems determines processing type. A Quick Refresher Interactive processing: user enters a command it is processed and a response is then given eg ATM machines, Checkouts, Ticket Sales. Real-time processing: processing is done immediately, as it is required eg Robot bump sensors. Batch Processing: transaction data is gathered in one large file and processed at some other time eg payroll processing.
Discussion Points Which type of processing would you suggest for: 1. a washing machine? 2. BACs payments of 1, 000 s of invoices? 3. a flight simulator for training pilots? 4. a back-up of millions of files? 5. answering customer enquiries? 6. creating bank statements? Explain why ATM machine do not use batch processing.
File Management The OS manage the files stored on backing storage devices. Backing stores both: Program files: contain all the instructions needed to run a program. Data file: are data documents produced when using a program. 2 features of a hierarchical file systems are folders and sub-folders.
Background Jobs Interactive OS let some jobs be done whilst letting you work on tasks. Those jobs are being completed in the background. Example You can continue to (foreground job) word process a document whilst you are printing (background job). How Can This Be Done? The operating system does jobs in the background by sharing CPU between the foreground and background tasks. Just think: can you type to keep up with a 3 GHz computer?
Device Drivers Operating Systems control all hardware devices. A device driver is a program ie a set of instructions, that enables the OS to control a peripheral device. Examples A new printer will come with a CD – printer driver. A webcam will come with a CD - webcam driver. If your hardware is not working properly, install it’s device driver.
Pupil Tasks Answer the following questions in your jotter. 1. List 2 features of hierarchical file management systems. 2. What is the difference between program and data files? 3. Briefly explain the Job Scheduler function of an OS. 4. What is meant by term a background job? 5. How are background jobs possible? 6. What is a device driver? 7. Your printer is printing rubbish, what would you suggest?
Additional Task Print then complete these worksheets. OS What am I. pdf OS Worksheet 1. pdf Check your answers to worksheet 1. OS Worksheet 1 answers. pdf