1. OPERATING SYSTEMS

2. Systems Software
Systems software is a type of software that controls the computers hardware. The operating system is one type of systems software

3. Functions Of The Operating SystemOS
User Interface
Memory/Disk Management
Multi-tasking
Peripheral Management and Drivers
User Management
File Management
The Operating System sits between your applications and the hardware of your computer.
It manages the hardware and software resources of the system.

4. Functions – 1. Manages Hardware
For example, when you wish to save a document, the application passes the document to the Operating System (OS).
The OS needs to use different instructions to save to a hard disc compared with a solid state drive.
The OS uses special software called a device driver to translate the specific instructions to save to that hardware.
Each different piece of hardware will have a device driver to communicate between the OS and the hardware.

5. Drivers – part of hardware management
A piece of software used to control a piece of hardware.
You may get drivers for graphics cards, mouse, sound card, network interface cards.
Drivers are OS specific and are regularly updated by companies

6. Functions – 2. Multi-tasking
The OS controls multi-tasking, making it look like the computer is running more that one program at once.
It does this by switching between programs very quickly – see next slide

7. Multitasking Time Task A Task B Task C Task D A B C D
If the tasks were split like this, we would have to wait until all Task A is complete, before completing Task B. A B C D
By giving the processor a small time slice for each task means that all tasks appear to be executing at the same time. In reality resources such as memory and the processor are being shared amongst tasks.

8. Functions –3.Memory Management
The OS controls the memory management, allocating RAM space to programs.
The OS allocates memory between the different programs that are open at the same time

9. Functions –3.File Management
Like memory management, the Operating System must identify where files are stored on long term storage (e.g. the hard disk drive or a solid state drive) when opening or storing files

10. 4. User Interface The OS provides a user interface.
This is what the user sees when they wish to use the computer system.
There are different types of user interfaces.
Command Line Interface
Text based
Raspberry Pi
Graphical User Interface
E.g. Windows 10, Apple watch

11. 5. User Management
User accounts - allow the ‘administrator’ to allocate specific users to specific software or to particular parts of the network, and protects personal files and programs from unauthorised access
Security - provides security through user accounts and passwords