What is java

 

1.What is java?

Ans.

Java refers to a number of computer software products and specifications from Sun Microsystems 

(the Java™ technology) that together provide a system for developing and deploying cross-platform 

applications. Java is used in a wide variety of computing platforms spanning from embedded devices and mobile phones on the low end to enterprise servers and super computers on the high end. Java is fairly ubiquitous in mobile phones, Web servers and enterprise applications, and somewhat less common in desktop applications, though users may have come across Java applets when browsing 

the Web.Writing in the Java programming language is the primary way to produce code that will be deployed as Java bytecode, though there are compilers available for other languages such as JavaScript, Python and Ruby, and a native Java scripting language called Groovy. Java syntax borrows heavily from C and C++ but it eliminates certain low-level constructs such as pointers and has a very simple memory model where every object is allocated on the heap and all variables of object types are 

references. Memory management is handled through integrated automatic garbage collection 

performed by the Java Virtual Machine (JVM)

1.OOP – Object Oriented Programming

OOP is a particular style of programming which involves a particular way of designing solutions to particular problems. Most modern programming languages, including Java, support this paradigm. When speaking about OOP one has to mention:

• Inheritance
• Modularity
• Encapsulation (binding code and its data)
• Polymorphism

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What is Supercomputer ?

 What is Supercomputer ?

Ans.

Supercomputer-

Supercomputers are one of the fastest computers currently available. Supercomputers are 

very expensive and are employed for specialized applications that require immense amount 

of mathematical calculations (number crunching).

For example, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic

calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting).

What is Minicomputer and Mainframe?

 What is Minicomputer and Mainframe?

Ans.

1. Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users simultaneously.

2.Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting hundreds

or even thousands of users simultaneously. Mainframe executes many programs concurrently

and supports many simultaneous execution of programs.

What is Workstation ?

 What is Workstation ?

Ans 

Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, 

software development, and other such types of applications which require a moderate amount 

of computing power and relatively high quality graphics capabilities.

Workstations generally come with a large, high-resolution graphics screen, large amount of 

RAM, inbuilt network support, and a graphical user 

interface. Most workstations also have mass 

storage device such as a disk drive, but a special 

type of workstation, called diskless workstation, 

comes without a disk drive.

Common operating systems for workstations are 

UNIX and Windows NT. Like PC, workstations are 

also single-user computers like PC but are typically 

linked together to form a local-area network, 

although they can also be used as stand-alone 

systems.

What is PC ?

 What is PC ?

Ans.

1. PC  (Personal Computer) 

A PC can be defined as a small, relatively inexpensive computer designed for an individual 

user. PCs are based on the microprocessor technology that enables manufacturers to put an 

entire CPU on one chip. Businesses use personal 

computers for word processing, accounting, 

desktop publishing, and for running spreadsheet 

and database management applications. At home, 

the most popular use for personal computers is 

playing games and surfing the Internet.

Although personal computers are designed as 

single-user systems, these systems are normally 

linked together to form a network. In terms of 

power, now-a-days high-end models of the 

Macintosh and PC offer the same computing power 

and graphics capability as low-end workstations by 

Sun Microsystems, Hewlett-Packard, and Dell.

                        

Fifth GenerationComputers

 5.Fifth GenerationComputers

Ans.

The period of fifth generation is 1980-till date. In the fifth generation, VLSI technology became

ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor

chips having ten million electronic components.

This generation is based on parallel processing hardware and AI (Artificial Intelligence)

software. AI is an emerging branch in computer science, which interprets the means and

method of making computers think like human beings. All the high-level languages like C and

C++, Java, .Net etc., are used in this generation

AI includes:

1. Neural Networks
2. Robotics
3. Development of expert systems to make decisions in real-life situations
4. Natural language understanding and generation

The main features of fifth generation are:

• ULSI technology
• Development of true artificial intelligence
• Development of Natural language processing
• Advancement in Parallel Processing
• Advancement in Superconductor technology
• More user-friendly interfaces with multimedia features
• Availability of very powerful and compact computers at cheaper rates

Fourth GenerationComputers

4. Fourth GenerationComputers

Ans.

The period of fourth generation was from 1971-1980. Computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements with their associated circuits on a single chip made it possible to have microcomputers of fourth generation.  

Fourth generation computers became more powerful, compact, reliable, and affordable. As a

result, it gave rise to Personal Computer (PC) revolution. In this generation, time sharing,

real time networks, distributed operating system were used. All the high-level languages like

C, C++, DBASE etc., were used in this generation.

The main features of fourth generation are:

• VLSI technology used
• Very cheap
• Portable and reliable
• Use of PCs
• Pipeline processing
•  Very small size
• No AC required
• Concept of internet was introduced
• Great developments in the fields of networks
• Computers became easily available

Some computers of this generation were:

1. DEC 10
2. STAR 1000
3. PDP 11
4. CRAY-1(Super Computer)
5. CRAY-X-MP(Super Computer)

Third GenerationComputers

 3.Third GenerationComputers

Ans.

The period of third generation was from 1965-1971. The computers of third generation used 

Integrated Circuits (ICs) in place of transistors. A single IC has many transistors, resistors,

and capacitors along with the associated circuitry. 

The IC was invented by Jack Kilby. This development made computers smaller in size, reliable,

and efficient. In this generation remote processing, time-sharing, multi-programming 

operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, 

BASIC, ALGOL-68 etc.) were used during this generation.

The main features of third generation are:

• IC used
• More reliable in comparison to previous two generations
• Smaller size
• Generated less heat
• Faster
• Lesser maintenance
• Costly
• AC required
• Consumed lesser electricity
• Supported high-level language

Some computers of this generation were:

1. IBM-360 series
2. Honeywell-6000 series
3. PDP (Personal Data Processor)
4. TDC-316
5. IBM-370/168

Second GenerationComputers

         2. Second GenerationComputers

Ans .

The period of second generation was from 1959-1965. In this generation, transistors were 

used that were cheaper, consumed less power, more compact in size, more reliable and faster 

than the first generation machines made of vacuum tubes. In this generation, magnetic cores 

were used as the primary memory and magnetic tape and magnetic disks as secondary 

storage devices. 

In this generation, assembly language and high-level programming languages like FORTRAN, 

COBOL were used. The computers used batch processing and multiprogramming operating 

system.

The main features of second generation are

• Use of transistors
• Reliable in comparison to first generation computers
• Smaller size as compared to first generation computers
• Generated less heat as compared to first generation computers
• Consumed less electricity as compared to first generation computers
•  Faster than first generation computers
•  Still very costly
•  AC required
• Supported machine and assembly languages

Some computers of this generation were:

1. IBM 1620
2. IBM 7094
3. CDC 1604
4. CDC 3600
5. UNIVAC 1108

First Generation Computers

 1.First Generation Computers

Ans.3

The period of first generation was from 1946-1959. The computers of first generation used 

vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing 

Unit). These tubes, like electric bulbs, produced a lot of heat and the installations used to fuse 

frequently. Therefore, they were very expensive and only large organizations were able to 

afford it

In this generation, mainly batch processing operating system was used. Punch cards, paper 

tape, and magnetic tape was used as input and output devices. The computers in this 

generation used machine code as the programming languacge.

The main features of the first generation are

1.Vacuum tube technology

2.Unreliable

3.Supported machine language only

4.Very costly

5.Generated a lot of heat

6.Slow input and output devices

7.Huge size

8.Need of AC

9.Non-portable

10.Consumed a lot of electricity

Some computers of this generation were:

1.ENIAC

2.EDVAC

3.UNIVAC

4.IBM-701

5.IBM-650

What is computer generation ?

 Q-2 What is computer generation ? 

Ans-

Generation in computer terminology is a change in technology a computer is/was being used. 

Initially, the generation term was used to distinguish between varying hardware technologies. 

Nowadays, generation includes both hardware and software, which together make up an 

entire computer system.

There are five computer generations known till date. Each generation has been discussed in 

detail along with their time period and characteristics. In the following table, approximate 

dates against each generation has been mentioned, which are normally accepted.

Following are the main five generations of computers.

1.First Generation-The period of first generation: 1946-1959. Vacuum tube based

2.Second Generation-The period of second generation: 1959-1965. Transistor based.

3.Third Generation-The period of third generation: 1965-1971. Integrated Circuit based.

4 Fourth Generation-The period of fourth generation: 1971-1980. VLSI microprocessor based.

5.Fifth Generation-The period of fifth generation: 1980-onwards. ULSI microprocessor based.

What is computer ?

Q.1 What is computer ?

Ans-

Today’s world is an information-rich world and it has become a necessity for everyone to know about computers. A computer is an electronic data processing device, which accepts and stores data input, processes the data input, and generates the output in a required format

         Functionalities of a Computer

• If we look at it in a very broad sense, any digital computer carries out the following five functions:

Setp 1.Takes data as input.

Setp 2.Generates the output.

Setp 3.Processes the data and converts it into useful information.

Setp 4.Stores the data/instructions in its memory and uses them as required

Setp 5.Controls all the above four steps.

            Advantagesof Computers

• Computer is a very fast device.
•  It is capable of performing calculation of very large amount of data.

The computer has units of speed in microsecond, nanosecond, and even the picosecond.

                      Accuracy

1. In addition to being very fast, computers are very accurate.
2. The calculations are 100% error free.
3. Computers perform all jobs with 100% accuracy provided that the input is correct.