OPERATING SYSTEM - FUNCTIONS
- Handles input and output
- Selects and controls the operation of the hardware devices such as keyboards, mice, scanners, printers etc.
- Recognises hardware device such as pen drive, camera etc. when they are attached to the computer and automatically loads the software (device driver) it needs to control the device.
- Supervises the running of other programs
- Provides a way for application programs like word processors, spreadsheets etc. to work with the hardware.
- Handles the storage of data
- Keeps track of all the files and folders on the disk.
- Maximises the use of computer memory
- Decides where in memory the program instructions are placed.
- Ensures the parts of the program needed frequently are put in fastest part of the memory.
- Handles interrupts and decides what action to take
- Alerts the user when errors like printer cannot print because of paper jam or it has run out of paper.
OPERATING SYSTEM - INTERFACE
Interface is used by the Operating System for interacting with the user.
Commonly used interfaces are:
Command Line Interface (CLI)
Graphical User Interface (GUI)
COMMAND LINE INTERFACE (CLI)
- For an experienced user typing in commands using CLI is quicker than moving the mouse or clicking.
- Uses less disk space than GUI when stored
- Requires lesser memory (RAM) when being used.
- Does not need powerful hardware like processor, graphics card to run a CLI.
- User needs to remember commands and their syntax.
- Commands must be issued in a specific order otherwise commands will be rejected.
- Difficult to operate for a beginner.
GRAPHICAL USER INTERFACE (GUI)
- User friendly - very easy to use for the novice user
- Has features such as Windows, Icons, Menus and Pointers (WIMP)
- No need to remember commands and its syntax.
- Can be operated using point and click method.
- Takes more storage space on the disk.
- Requires more memory (RAM) when being used.
- Powerful hardware like processor, graphics card are needed to run latest version of a GUI.
- Experienced user might find that typing in commands is quicker than moving the mouse or clicking.
Q: Graphical User Interfaces are very popular interfaces that are used with computers, mobile phones and other portable devices.
(a) Give three features of a graphical user interface 
Q: All computers need an Operating system.
(a) Explain what an operating system is. 
(b) List three functions of an operating system. 
Q: Name any one device other than computer and mobile that has GUI.
Q: List any two benefits of having this interface.