FUNCTIONS OF OPERATING SYSTEM
1) STARTING THE COMPUTER
- The first function of an operating system is to start the computer. When we start a computer, it loads the operating system into the computer's memory. This process is called booting. Booting means to load and initialize the operating system on a computer machine. It can happen in two ways: warm boot or cold boot.
i) WARM BOOT
A warm boot means restarting a computer that is already on.It normally happens after installing a new software or hardware or after an application crashes or stops working.
ii) COLD BOOT
A cold boot means starting a computer that is already off. It happens when we turn on a computer that has been completely powered off.
2) PROVIDING A USER INTERFACE
- From the user's perspective, the most important function of an operating system, is providing the user interface. This function controls how the user enters data and instruction and how information is displayed.
- The user interface typically enables users:
to start an application program
to manage disks and files such as formatting, copying and renaming
to shut down the computer safely by following the correct procedures
- The three types of user interface are Command-Line, Menu-Driven and Graphical User Interface (GUI).
3) MANAGING DATA AND PROGRAMS
- The next function of an operating system is to manage data and programs. When we start an application, the CPU loads the application from storage into memory.
- In the early days of personal computing, single-tasking operating systems could run only one application at a time.
- Multitasking operating systems enable users to work with two or more application programs at the same time.
4) MANAGING MEMORY
- The computer's operating system is responsible for managing memory such as:
optimizing the use of random access memory (RAM)
allocating data and instruction to an area of memory while being processed
monitoring the contents of memory
releasing data and instructions from being monitored in memory when the process is done
5) CONFIGURING DEVICES
- Another function of an operating system is handling input and output, as well as enabling communication with input and output devices. Most operating systems come with drivers for popular input and output devices.
- These drivers install new devices and check whenever there is conflict with these devices.
THE IMPORTANCE OF USER INTERFACES
- The user interface is the part of an operating system that you see and interact with and by which users and programs communicate with each other.
- The importance of user interfaces are:
to assist users interacting with a software
to control how a user enters data and instructions
to control how information is displayed
1) COMMAND-LINE USER INTERFACE
- The command-line user interface requires a user to type commands or press special keys on the keyboard to enter data and instructions that instruct the operating system what to do. It has to be typed one line at a time.
- The command-line user interface is difficult to use because it requires exact spelling, syntax or a set of rules of entering commands and punctuation.
- We must observe the complicated rules of syntax that specify exactly what you can type in a given place.For example, if we want to rename a filename from ABC.txt to DEF.txt we use the following command.
- The command-line user interface also requires memorisation. It is also easy to make a typing mistake. The advantage of command-line interface is, it helps the user to operate the computer quickly after memorizing the keywords and syntax.
2) MENU DRIVEN INTERFACE
- Menu-driven user interface enables the user to avoid memorizing keywords such as copy, paste and syntax. On-screen, menu-driven interface provide menus as means of entering commands. It shows all the options available at a given point in a form of text-based menu. Menu-driven user interfaces are easy to learn.
3) GRAPHICAL USER INTERFACE (GUI)
- Graphical user interface makes use of the computer’s graphics capabilities to make the operating system and programs easier to use, which is also called ‘user-friendly’. On today’s PCs and Macintoshes, GUIs are used to create the desktop that appears after the operating system finishes loading into memory.
- We can easily differentiate the interfaces between Mac OS, Windows XP or Linux by looking at their desktops. Graphical user interface interact with menus and visual images such as buttons, icons and other graphical objects to issue commands.
- On the desktop, we can initiate many actions by clicking icons that represent computer resources such as files, programs and network connections. Graphical user interface is commonly used and has become a standard.
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