Deadlock is a specific situation or condition where two processes are waiting for each other to complete so that they can start. But this situation causes hang for both of them.

Thrashing is a phenomenon in virtual memory scheme when the processor spends most of its time in swapping pages, rather than executing instructions.

As many as processors are increased, you will get the considerable increment in throughput. It is cost effective also because they can share resources. So, the overall reliability increases.

Demand paging specifies that if an area of memory is not currently being used, it is swapped to disk to make room for an application's need.

Paging is used to solve the external fragmentation problem in operating system. This technique ensures that the data you need is available as quickly as possible.

A program while running or executing is known as a process.

A list of different states of process:

New Process
Running Process
Waiting Process
Ready Process
Terminated Process

An executing program is known as process. There are two types of processes:

Operating System Processes
User Processes

Real-time system is used in the case when rigid-time requirements have been placed on the operation of a processor. It contains a well defined and fixed time constraints.

A socket is used to make connection between two applications. Endpoints of the connection are called socket.