what is computer?

computer

A computer is a machine with electrical and elctronic components that receives data (input) stores and process the data according to a given set of information and give result (output)and stores for future purpose that is called computer .

                               Originally computer means to calculate of or process information that is called computer.

History of computer

Father of the computer is "charles babbage" He is an English mathematician and he invented the computer in 1833 and his machine name was "Analytical Engine" which means "A machine which could calculate and print tables of functions using limited techniques".

Analytical Engine

Analytical Engine had four parts . A mill, which is the section which did the calculations , essentially the cpu; the store , were the iformation was kept recorded, essentially the memory ; the reader , which would allow data to be entered using punched cards, essentially the keyboard, and the printer.

The generation of computers are characterized by a major technological development that fundamentally changed the way computers operate, resulting in increalingly smaller, cheaper,more powerful and more efficient and reliable devices. the various generations of computers are listed below.

Generation of computers

generation of computers under we talk about total generation of computer like first generation computers , second generation computers, third generations computers , fourth generation computers and last one is  fifth generation computers.

First generation computer

First Generation: Vacuum Tubes (1940-1956) The first computer systems used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. the digital computers using vavles (vaccum tubes) are known as first generation computers. the first generation computers was very expensive and very high rate normal people didn't buy that computer only rich persons buy . the first generation computers was stored information in the form of propagating sound waves.

    The vaccum tubes use lot of electricty or power . there are following first generation computers are mention in below :-

Mark 1: 

mark1 computer 

The IBM Automatic Sequence Controlled Calculator (ASCC), called Mark I by Harvad university's staff,^[1] was a general purpose electromanchincal computer that was used in the war effort during the last part of world war II .

One of the first programs to run on the Mark I was initiated on 29 March 1944 by John von Neumann. At that time, von Neumann was working on the Manhattan project, and needed to determine whether implosion was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables, which had been the initial goal of British inventor Charles Babbage for his "analytical engine". 

ENIAC (Electronic numerical integrator and calculator)

ENIAC

 ENIAC was formally dedicated at the University of Pennsylvania on February 15, 1946 and was heralded as a "Giant Brain" by the press.^[10] It had a speed on the order of one thousand times faster than that of electro-mechanical machines; this computational power, coupled with general-purpose programmability, excited scientists and industrialists alike. The combination of speed and programmability allowed for thousands more calculations for problems, as ENIAC calculated a trajectory in 30 seconds that took a human 20 hours (allowing one ENIAC hour to displace 2400 human hours).^[11] The completed machine was announced to the public the evening of February 14, 1946 and formally dedicated the next day at the University of Pennsylvani. 

                                                       it was  developed by john Eckert and john mauchy from USA.

the ENIAC was 30-50 feet long , weighted 30 tons , contained 18000  vaccum tubes , 70000 resisters , 10000 capacitors and required 150000 watts of electricity. Today computer is many times as powerful as 

ENIAC, still size is very small.

EDAVC(Electronic Discrete Variable Automatic computer)

EDVAC (Electronic Discrete Variable AutomaticComputer) was one of the earliest electroniccomputers. Unlike its predecessor the ENIAC, it was binary rather than decimal, and was a stored-programcomputer. EDVAC was developed by jhon Eckert and jhon mauchy in 1950. The concept of storing data and instructions inside the computer was introduced here. this allowed much faster operation since the computer had rapid access to both data and instrucrion was that computer could do logical decision internally. The EDAVC was a binary serial computer with automatic addition ,subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory.

EDSAC(Electronic Delay Storage Automatic Computer)

it was developed by M.V.Wilkes at cambridge University in 1949. The EDSAC first stored - program computer . the EDSAC performed computations in the three millisecond range. It perfomed arithmetic and logical operations without human arithmetic and logical operations without human intervention. The key to the succes was in the stored instructions which it depended upon solely for its operation.

UNIVAC(universal Automatic computer)

it was the first commercial computer developed by united states in 1951. The machine was 25 feet by 50 feet in length , contained 5,600 tubes, 18000 crystal diodes, and 300 relays. It utilized serial circuitry, 2.25 mhz bit rate, and had an internal storage capacity 1000 wpeds or 12000 characters.

Second Generation 

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 −

• IBM 1620
• IBM 7094
• CDC 1604
• CDC 3600
• UNIVAC 1108

Third Generation

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, multiprogramming 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
• Fasterat
• Lesser maintenance
• Costly
• AC required
• Consumed lesser electricity
• Supported high-level language

Some computers of this generation were −

• IBM-360 series
• Honeywell-6000 series
• PDP (Personal Data Processor)
• IBM-370/168
• TDC-316

• Fourth Generation 

An IC containing about 100 components is called LSI (large scale integeration) and the one , which has more than 1000 such components is called as VLSI( very large scale integeration).

  It uses large scale integrated circuits (LSIC) built on a single silicon chip called microprocessors it is possible to place computer's central processing unit (CPU) on single chip These computers are called microcomputers.

 Later very large scale integrated circuits (VLSIC) replaced (LSICs). Thus the computer which was occupying a very large room in eariler days can now be placed on a table . The personal computer(pc)that you see in your school is a fourth generation computer main memory used fast semiconductors chips up to 4 M bits size. Some of the Fourth generationn computers are IBM Pc , Apple - macintosh ,etc.

The main features of fourth generation are −

• VLSI technology used
  
• Very cheap
• Portable and reliable
• Use of PCs
• Very small size
• Pipeline processing
• 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 −

• DEC 10
• STAR 1000
• PDP 11
• CRAY-1(Super Computer)
• CRAY-X-MP(Super Computer)

Fifth Generation

The fifth generation of computing is supposedly comprised of today's very modern and advanced computer technology. It can be defined in many different ways. The advance in machinery has very much furthered in recent decades. Things have been created that would have been down right unimaginable to those from say generations 1 and 2. We as humans are only building off of inventions that have come before ours, which makes the importance we put on computer technology more and more relevant. How did we come from building the 30- ton ENIAC 1 to desiring the thinnest, fastest laptop computer on the market? Computers started out as just simple calculators. Now, they basically do much of our jobs for us. It truly is something bafflingly amazing. 

The fifth generation of computers was invented in 1980 till today. The fifth generation of computers was invented by James Maddox who created a parallel computing system. They use the Ultra Large Scale Integration (ULSI) technologies which lead to the production of microprocessor chips. They have ten million electronic components. This generation mainly deals with parallel processing hardware and artificial Intelligence software.

AI includes −

• Robotics
• Neural Networks
• Game Playing
• Development of expert systems to make decisions in real-life situations
• 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

Some computer types of this generation are −

• Desktop
• Laptop
• NoteBook
• UltraBook
• ChromeBook