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(a) React OS

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.

1. Allocating memory is easy and cheap

2. Any free page is ok, OS can take first one out of.list it keeps

3. Eliminates external fragmentation

4. Data (page frames) can be scattered all over PM 

5. Pages are mapped appropriately anyway 

6. Allows demand paging and pre – paging 

7. More efficient swapping

8. No need for considerations about fragmentation 

9. Just swap out page least likely to be used

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.

Different server distributions in Linux OS:

1. Ubuntu

2. Linux Mint 

3. Debian 

4. Fedora 

5. RedHa.

(a) JELLY BEAN

A Mobile Operating System (or mobile OS) is an operating system that is specifically designed to run on mobile devices such as phones, tablets, smart watches, etc.

Example: Apple IOS

Google android :

Android is a mobile OS developed by Google, based on Linux and designed for smart phones and tabs. iOS was developed by Apple.

Example : Android, ColorOS, LGUX, MIUI.

Advantages and disadvantages of Time Sharing Option (TSO)

Advantages:

• Each task and each user get its time.
• Systems have to give time to these application individual tasks and other applications also, so that all system behave correctly.
• Reduces the CPU ideal time

Disadvantages:

• Problem in Reliability
• It consumes many resources so it need special operating systems.
• Need High specification hardware

Different operating system used:

1. Single user, single Task Operating system

2. Multi user operating system

3. Multiprocessing operating system

4. Distributed Operating system

(c) Both a & b

Dotnut is not an android moblie open source versions.

Resources can be used in different locations. Improves interaction with customers and clients. Reduces load on host computers. The data can be exchanged via email and chat.

Android:

Android is a mobile operating system developed by Google, based on Linux and designed primarily for touch screen mobile devices such as smart phones and tablets. Google has further developed Android TV for televisions, Android Auto for cars and Android Wear for wrist watches, each with a specialized user interface. Variants of Android are also used on game consoles, digital cameras, PCs and other electronic gadgets.

Android is a mobile operating system developed by Google, based on the Linux and designed primarily for touch screen mobile devices such as smart phones and tablets.

This is the operating system that provides a GUI through which the user can navigate and interact.

Security Management features: 

1. File access level security

2. System level security 

3. Network level securny.

1. Keeping track of which portion of memory are currently being used and who is using them.

2. Determining which processes and data to more in and out of memory.

3. Allocation and de – allocation of memory blocks as needed by the program in main memory. (Garbage collection).

Raspbion os is a platform that is designed to teach how to build a computer, working principle of every part of a circuit board, write code apps or games. The platform is available in pre – designed kits.

An os allows only a single user to perform a task at a time. It is called as a single user and single task os. 

Example : MS – DOS.

A software is a set of instructions that perform specific task. It interacts basically with the hardware to generate the desired output. Types of Software:

Software is classified into two types:

1. Application Software

2. System Software

Application Software:

Application software is a set of programs to perform specific task.

For example MS-word is an application software to create text document and VLC player is familiar application software to play audio, video files and many more.

System Software:

System software is a type of computer program that is designed to run the computer’s hardware and application programs.

For example Operating System and Language Processor.

iOS (formerly iPhone OS) is a mobile Operating System created and developed by Apple Inc., exclusively for its hardware. It is the Operating System that presently powers many of the company’s mobile devices, including the iPhone, iPad and iPod Touch. It is the second most popular mobile Operating System globally after Android.

Operating systems for mobile devices: Mobile devices such as phones, tablets and MP3 players are different from desktop and laptop computers and hence they need special Operating Systems. 

Examples of mobile Operating Systems are Apple iOS and Google Android. The iOS running on an iPad is Operating systems for mobile devices generally are not as fully featured as those made for desktop and laptop computers and they are not able to run all software.

1. Any type of data in a computer is stored in the form of flies and directories / folders through File Allocation Table (FAT).

2. The FAT stores general information about files like file name, type (text or binary), size, starting address and access mode (sequential / indexed / indexed – sequential / direct / relative).

1. The operating systems should be robust.

2. When there is a fault, the operating system should not crash, instead the os have fault tolerance capabilities and retain the existing state of system.

1. Scheduling processes and threads on the cpu.

2. Creating and deleting both user and system processes.

3. Suspending and resuming processes.

4. Providing mechanisms for process synchronization.

5. Providing mechanisms for process communication.

A computer consists of a collection of process they are classified as two categories:

1. Operating system process which is executed by system code.

2. User processes which is executed by user code.

A process means program in execution. It generally takes an input, processes it and gives us the appropriate output. Check Introduction to Process Management for more details about a process. There are basically 2 types of processes.

1. Foreground processes: Such kind of processes are also known as interactive processes. These are the processes which are to be executed or initiated by the user or the programmer, they can not be initialized by system services. Such processes take input from the user and return the output. While these processes are running we can not directly initiate a new process from the same terminal.
2. Background processes: Such kind of processes are also known as non interactive processes. These are the processes that are to be executed or initiated by the system itself or by users, though they can even be managed by users. These processes have a unique PID or process if assigned to them and we can initiate other processes within the same terminal from which they are initiated.

The main use of Operating System is

1. to ensure that a computer can be used to extract what the user wants it do.

2. Easy interaction between the users and computers.

3. Starting computer operation automatically when power is turned on (Booting).

4. Controlling Input and Output Devices

5. Manage the utilization of main memory.

6. Providing security to user programs.

1. Honey comb

2. Jelly Bean

3. Kitkat

4. Lollipop

5. Marshmallow

6. Nougat

User Interface:

User interface is one of the significant feature in Operating System. The only way that user can make interaction with a computer. If the computer interface is not user – friendly, the user slowly reduces the computer usage from their normal life. This is the main reason for the key success of GUI (Graphical User Interface) based Operating System. 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. Beginners are impressed by the help and pop up window message boxes. Icons are playing vital role of the particular application.

Now Linux distribution is also available as GUI based Operating System. The following points are considered when User Interface is designed for an application.

1. The user interface should enable the user to retain this expertise for a longer time.

2. The user interface should also satisfy the customer based on their needs.

3. The user interface should save user’s precious time. Create graphical elements like Menus,Window,Tabs, Icons and reduce typing work will be an added advantage of the Operating System.

4. The ultimate aim of any product is to satisfy the customer. The User Interface is also designed to satisfy the customer.

5. The user interface should reduce number of errors committed by the user with a little practice the user should be in a position to avoid errors (Error Log File)

Since ΔG is negative, the reaction is feasible. But certain amount of activation energy is required for this reaction to occur and hence it will not take place at room temperature (heating is required).

The sulphide ores are converted into oxides by heating them strongly in the presence of excess air. This process is called. The metals in the middle of the activity series such as iron, zinc, lead, copper, etc., are moderately reactive. These are usually present as sulphides or carbonates in nature.

1. Liquid

2. Elastic

3. Gas

4. Compressible

5. Gas

6. 150 °C

7. 100 °C

Given: v = 8 cm³ , d = 3.0 g/cm³

To find: m = ?

Formula: density (d) =\(\cfrac{mass(m)}{volume(v)}\)

Solution:

From formula,

m = d × v

= 3.0 g/cm³ × 8 cm³

= 24 g

\(\therefore\) Mass of the object = 24 g

Given: m = 158 g, d = 7.9 g/cm³

To find: v = ?

Formula: density (d) = \(\cfrac{mass(m)}{volume(v)}\)

Solution:

From formula,

v = \(\cfrac{m}{d}\)

\(=\cfrac{158\,g}{7.9\,g/cm^3}=20\,cm^3\)

\(\therefore\) The volume of iron block = 20 cm³

Condensation is the process which creates clouds.

i. Naphthalene balls sublimate at room temperature.

ii. All its molecules go into vapour phase without changing into liquid.

iii. This process takes place when naphthalene balls absorb heat energy from the surrounding, which occurs slowly but continuously.

Hence, naphthalene balls disappear over a period of time, without leaving behind any solid particles.

Particles of a solid cannot move much. This is one of the physical characteristics of solids.

The particles in a solid are bound to each other by a force .

Matter has volume and mass.

Phase describes a physical state of matter.

Condensation is the process which creates clouds and is essential for snow and rain formation.

World of Matter is made up of very tiny particles.

i. At 257 °C, water is in gaseous state.

ii. At 100 °C, water co-exists in liquid and gaseous state.

iii. At 0 °C, water co-exists in the solid and liquid state.

(B) 0 °C

The melting point of ice is 0 °C.

The mass of an object gives an indication of the amount of matter that an object contains.

Surface area, temperature, humidity, wind speed, etc. are the factors which affect the rate of evaporation of liquid.

(C) 100 °C

The boiling point of water is 100 °C.

(A) freezing point

The freezing point of a liquid is the temperature at which the liquid gets converted into solid.

(B) solid and gas

The phases A and C are solid and gas respectively.