Transcript Operating Systems - Mid Yell Junior High School

Operating Systems
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
Controls main memory storage of programs and data, enabling multi-programming.
2.
Provides the HCI (Human Computer Interface)
3.
File Management
4.
Controls Input/Output Devices
5.
Job Scheduler
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
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 1,000s 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 store 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