Understanding Operating Systems (OS)


An operating system is the most important software that runs on a computer. It manages the computer's memory, processes, and all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer's "language." Without an operating system, a computer is useless.


 Purpose of an operating system
Regardless of the size and complexity of the computer and the operating system, all operating systems perform the same four basic functions:
1. Control hardware access - The operating system manages the interaction between applications and the hardware.
2. Files and Folder Management - The operating system creates a file structure on the hard disk drive to allow data to be stored.
3. User interface - The operating system enables the user to interact with software and hardware. There are two types of user interfaces namely:
· Graphical User Interface (GUI) –
· Command Line Interface (CLI)
 
Command Line Interface (CLI)

This is where the user types commands at a prompt. See the video below:
When you switch on the computer and after running the Operating System a command prompt line appears like the one below:
C:\
To see a list of the files you need to type dir and press Enter on the prompt command line like this:
C:\ dir
Press Enter and a list of files and directories will be displayed.
The MS-DOS operating system uses the command line interface.
The main disadvantage is that the user must know the commands, their spelling and syntax and when to use them.
Graphical User Interface (GUI) –
The user interacts with menus and icons. Most operating systems, from Windows 95 to Windows 8 include both a GUI and a CLI.
Another purpose of OS is Application management - The operating system manages all programs to ensure that the correct resources are allocated to the applications.  

Click on the image below to watch a full video on how windows 7 works.
Booting a computer: The process of loading the Operating System is known as Booting, which is the process of switching on a computer. As electric power is detected the computer runs a program which fetches the Operating System from the HARD DISK and leaves it running in the computer memory to control all other programs. The user does not participate during this process if the Operating System is installed properly.

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