What is Program Counter? What information does it store?

Program Counter is a register inside a processor that contain address of the next instruction to be executed. After executing an instruction,  program counter contents are incremented by the length of the instruction that is read,  recently so that it again contain the address of next instruction to be executed.

List the desirable features of an algorithm?

(a) Top to down structured flow.
(b) Large algorithms must be broken into smaller ones with minimum coupling between them.
(c) The modules must be as independent as possible. That is high cohesion must be there.
(d) It must be easy to implement with minimum memory and must be fast.

What is a Router?

Router is a device used to determine the routes that a packet must take upon arrival at its input line. Routers decide the routes dynamically or statistically. They operate in network layer.

What is Bridge?

It is a device that is used to connect two LANs together. They LAN's can be of different type. Bridge receives packets from one LAN and convert the packet into a form acceptable for another LAN of different type. Bridges operate at data link layer.

What is a key word and what are the restrictions of using them?

Key word is a word with special meaning. For example in C programming language words int, float etc are key words. The users are not supposed to use key words as variable names.

Distinguish between the data and information?

Data is a collection of useful values. Processed data gives information. Collection of marks obtained by students is raw data. When sorted it gives the student marks rank wise. This is information.

What is Telnet?

It is a popular client server application program. TELNET is an abbreviation for terminal network. It is a standard application layer protocol that provides an interface through which a program on a host can access the resources of another host.

How does a 'while' control structure differ from 'do while ' structure?

The while loop first check the condition given in the while statement. If this condition is satisfied, then the statements in the while loop is executed.

In 'do while ' loop first the statements in the loop are executed then the condition is checked. If condition is true then again the statements are executed. In do while loop at least once the statements in the loop are guaranteed to be executed.

What is memory management? Why is it essential in a multi -user environment?

Memory management is schemes for using the available memory in a computer system in an effective manner. Memory management is one of the very important task performed by operating system.
In multiuser systems,  multiple processes reside in memory at the same time. Each process belong to different users. In order to avoid one process from interfacing with another process area, proper memory management is required. Usually available memory is partitioned and each process is allowed to reside in a separate partition. If a process try to violate the alloted memory space then it is detected automatically and the process is suspended. All these activities are done by operating systems memory management modules.

What is EPROM? How is it different from PROM?

EPROM: Erasable and programmable read only memory. It is a type of semiconductor read only memory in which contents can be erased and rewritten any number of times. To erase either electrical signals are used.

PROM: Programmable read only memory. It is read only memory which can be programmed only once. Any number of read operation can be done. To program the PROM internal fuses are burnt, connecting or disconnecting transistors, which acts as switches internally.

Why are NAND and NOR gates called universal gates?

NAND and NOR gates are called universal gates because any boolean function can be implemented using NAND or NOR gates only.

What is meant by Compiling a program?

Compiling is the process of translating a high level language program into its machine language form. For the purpose of compilation, software called Compilers are used.

What is ternary operator? Is any such operator available in C language? If yes, explain with an example?

In C ternary operator is available and is denoted by symbol? :

A traditional C statement and its equivalent C ternary construct is shown below :

If A==0
Else X=0;
X=A==0? 1:0;