The distributors are
(i) BOSS
(ii) Ubuntu
(iii) Mint
(iv) Fedora
(v) Redhat
(vi) Debian
(vii) Google's Android
(viii) Chrome OS and Chromium OS

(i) It is open source OS.
(ii) It can be modified and distributed by anyone.
(iii) It is easy to customize.
(iv) There are many distributors.

Storage Management creates various methods, tables and. trees to store data efficiently, so the user won't have to mention addresses as to where to store data.

Paged allocation divides the computer's primary memory into fixed-size units called page frames.

It is a part of OS which is visible to the user and has to be understood by the user.

It is a Graphical User Interface through which the user can easily navigate and interact with the system. It is more user friendly OS.

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.

An operating system allows a single user to perform a task at a time. It is called as Single user and single Task operating system.

The different types of operating system uscd in the computer:
(i) Single User and Single Task Operating Systems
(ii) Multi User Operating Systems
(iii) Multi Pocessing Operating Systems
(iv) Distributed Operating Systems
(v) Prominent Operating Systems

Multi-processing is a one of the features of Operating System. It has two or more processors for a single running process (job). Processing takes place in parallel is known as parallel processing.

The Operating System provides three levels of securities to the user end. They are
(i) File access level
(ii) System level
(ill) Network level.

Ubuntu, Mint, Fedora, RedHat, Debian, Google's Android. Chrome OS, Chromium OS.

The GUI is a window based system with a pointing device to direct I/O, choose from menus, make selections and a keyboard to enter text. Its vibrant colours attract the user very easily.

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

(i) To ensure that a computer can be used to extract what the user wants it do.
(ii) Easy interaction between the users and computers