(i) Internet
(ii) Intranet

(i) It is used in computers and laptops that allow same data and applications to be accessed by multiple users at the same time.
(ii) The users can also communicate with each other. Windows, Linux and UNIX are examples for multi user Operating System.

A task is a function such as printing a document, writing a file to disk, editing a file or downloading a file etc. MS-DOS is an example for a single user and single task Operating System.

(i) Controlling input and output devices
(ii) Managing the utilization of main memory.

(i) BOSS
(ii) Unix
(iii) Ms-DOS

GUI is used in Windows because it provides an interaction between the windows OS and the user.

An operating system is a system software which serves as the interface between a user and a computer.

It refers to the softwares which are available for use at no cost or for an optional fee.

Different operating system used:
1. Single user, single Task Operating system
2. Multi user operating system
3. Multiprocessing operating system
4. Distributed Operating system

Multiprocessing is one of the features of operating system. It has two or more processors for a single running process. Each processor works on different parts of the same task or two or more different tasks.

Security Management features:
File access level security, System level security, Network level security.

Different server distributions in Linux OS:
Ubuntu, Linux Mint, Debian, Fedora, RedHat.

GUI - Graphical User Interface - It allows the use of icons or other visual indicators to interact with electronic devices, rather than using only text via the command line. For example, all versions of Microsoft Windows utilize a GUI, whereas MS-DOS does not.

A Multi-user Operating system is a computer operating system (OS) that allows multiple users on different computers or terminals to access a single system with one OS on it.

(i) Keeping track of which portion of memory are currently being used and who is using them.
(ii) Determining which processes (or parts of processes) and data to move in and out of memory.
(iii) Allocation and de-allocation of memory blocks as needed by the program in main memory. (Garbage Collection).