Types of computer

When people think “computers,” usually it’s something like a laptop or your office computer that comes to mind. Computers are actually all around us, and can be broken down into separate categories depending on their size and processing power. Certain definitions have changed over time with the speedy advances in technology – we have computers that can fit in the palm of our hands now that have as much processing power as a computer that was the size of a whole room half a century ago! Still, most of the general qualifications for each category are the same, along with the many subcategories that might fit into each one.

So what are these categories of computer types? There are five main ones: supercomputers, mainframe computers, minicomputers, microcomputers, and finally mobile computers. In this guide, we’ll learn the details of each one, plus provide some useful resources for learning more about computer basics. For the essentials, you can start out with this introductory computer class.

Below you’ll find an extensive, descriptive list of the five types of computers, from supercomputers to mobile computers, and everything in between. If you’re interested in a career in engineering, check out this lecture course on computer science.

Supercomputers

A supercomputer is pretty much exactly what it sounds like. It’s a term used to describe computers that have the most capable processing power of its time. Early supercomputers in the 60s and 70s used just a couple processors, while the 90s saw supercomputers with thousands of processors at a time. Today, modern supercomputers run hundreds of thousands of processors, capable of computing quadrillions of calculations in just a few nanoseconds. You probably won’t be needing that kind of power to access Facebook… Actually, supercomputers are used in computational science to calculate and carry out a plethora of complex tasks. Modeling molecular structures, weather forecasting, and the field of quantum mechanics, among others, rely on supercomputers and their intense processing power to solve their equations.

Mainframe Computers

Like supercomputers, mainframe computers are huge, towering machines with lots of processing power. Mainframe computers are mostly used by corporations, government agencies, and banks – organizations that need a way to store large quantities of information. They are not the same as supercomputers. The processing capabilities of mainframe computers are measured in MIPS, or millions of instructions per second. Supercomputers, on the other hand, are measured in FLOPS, or floating point operations per seconds.

Minicomputers

A minicomputer is a multiprocessing machine that can support up to about 200 users at the same time. It’s like a less powerful mainframe computer, and is about the size of a refrigerator. A server can be an example of a minicomputer, but not all servers are minicomputers. Despite their name, a minicomputer is not a personal computer like the desktop machine you might have at home or work. They are much larger than that. Because of the ways microcomputers – which we’ll cover next – have excelled in processing power even beyond minicomputers, and at a much smaller size, minicomputers have become pretty much obsolete.

Microcomputers

Microcomputers are the ones people are most familiar with on a daily, non-professional basis, but of course that doesn’t mean they’re exclusive to the home. Microcomputers are smaller computers that run on microprocessors in their central processing units. They are much, much cheaper than supercomputers, mainframe computers and even minicomputers, because they’re meant for everyday uses that are more practical than professional. The range of capabilities for microcomputers are still vast, though. A film editor might use a microcomputer to run many intensive editing programs at once, while a student might use a microcomputer for Facebook and word processing. Need help with the basic functionality of microcomputers

Generations of computer

"Generation" in computer talk is a step in technology.originally, the term "generation" was used to distinguish between varying hardware technologies but it has know become extended to include both hardware and software that together make up a computer system.

The First Generation: 1945-1956 (The Vacuum Tube Years)

The first generation computers were huge, slow, expensive, and often undependable. In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC (Electronic Numerical Integrator and Computer) electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I. The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do. The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and the UNIVAC I (UNIVersal Automatic Computer). The vacuum tube was an extremely important step in the advancement of computers. Vacuum tubes were invented the same time the light bulb was invented by Thomas Edison and worked very similar to light bulbs. It's purpose was to act like an amplifier and a switch. Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it). Vacuum tubes could also stop and start the flow of electricity instantly (switch). These two properties made the ENIAC computer possible. The ENIAC gave off so much heat that they had to be cooled by gigantic air conditioners. However, even with these huge coolers, vacuum tubes still overheated regularly. It was time for something new.

Mauchly and Eckert: The ENIAC

 

The first general-purpose electronic computer appeared in 1946. it was developed by John William Mauchly and John Presper Eckert. They called their machine the Electronic Numerical Integrator and Computer (ENIAC).

ENIAC--1946

Unlike previous counting tools, ENIAC had no mechanical parts, no counters, and no gears. it relied solely on vacuum tubes. Each vacuum tube contained an electronic circuit, a tiny pathway that carried electricity. Each circuit could turn on and off very much the way a light bulb does.

ENIAC operated 1000 times faster than Mark I. It could do 5000 additions per second and 300 multiplications. The cost of this machine was around 3 million dollars.

However, ENIAC had a number of problems. It's 19,000 vacuum tubes took up so much space that it required a room measuring 20 feet by 40 feet! The tubes also produced a lot of heat and were always burning out. On average, 50 tubes burned out each day. Today, for a few cents, you can buy one chip that has more computing power than ENIAC!

John von Neumann & the EDSAC--1949

In 1946 a mathematician named John von Neumann proposed two changes in computer design: (1) The machine's instructions, he said, should be stored inside the computer. (2) Because electronic circuits are either on or off, he suggested that people use a series of 0's or 1's to code all the information they put into the computer. A zero would stand for off; a one would stand for on. This code is called the binary code and is still used today.

The EDSAC (Electronic Delay Storage Automatic Computer) had 3,000 vacuum tubes and the programs were input using paper tapes.

Eckert and Mauchly & the UNIVAC--1951

In 1951, Eckert and Mauchly designed another computer called the UNIVAC (UNIVersal Automatic Computer). It was the first computer to be sold to businesses. UNIVAC contained 5,400 vacuum tubes and used magnetic tapes to give instructions to the computer. The UNIVAC was used to predict the presidential election of Dwight Eisenhower. No one believed the machines prediction at first, but it was very accurate.

The Second Generation: 1956-1963 (The Era of the Transistor)

The transistor computer did not last as long as the vacuum tube computer lasted, but it was no less important in the advancement of computer technology. In 1947 three scientists, John Bardeen, William Shockley, and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever. This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

There were obvious differences between the transistor and the vacuum tube. The transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube. One transistor replaced the equivalent of 40 vacuum tubes. these transistors were made of solid material, some of which is silicon, an abundant element (second only to oxygen) found in beach sand and glass. Therefore, they were very cheap to produce. Transistors were found to conduct electricity faster and better than vacuum tubes. They were also much smaller and gave off virtually no heat compared to vacuum tubes. Their use marked a new beginning for the computer. Without this invention, space travel in the 1960's would not have been possible. However, a new invention would even further advance our ability to use computers.

The Third Generation: 1965-1970 (Integrated Circuits-Miniaturizing the Computer)

Transistors were a tremendous breakthrough in advancing the computer. However, no one could predict that thousands even now millions of transistors (circuits) could be compacted in such a small space. The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits. Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

Since the invention of integrated circuits, the number of transistors that can be placed on a single chip has doubled every two years, shrinking both the size and cost of computers even further and further enhancing its power. Most electronic devices today use some form of integrated circuits placed on printed circuit boards--thin pieces of bakelite or fiberglass that have electrical connections etched onto them--sometimes called a mother board.

These third generation computers could carry out instructions in billionths of a second. The size of these machines dropped to the size of small file cabinets. Yet, the single biggest advancement in the computer era was yet to be discovered.

The Fourth Generation: 1971-Today (The Microprocessor)

This generation can be characterized by both the jump to monolithic integrated circuits (millions of transistors put onto one integrated circuit chip) and the invention of the microprocessor (a single chip that could do all the processing of a full-scale computer). By putting millions of transistors onto one single chip more calculation and faster speeds could be reached by computers. Because electricity travels about a foot in a billionth of a second, the smaller the distance the greater the speed of computers.

However, what really triggered the tremendous growth of computers and its significant impact on our lives is the invention of the microprocessor. Ted Hoff, employed by Intel (Robert Noyce's new company) invented a chip the size of a pencil eraser that could do all the computing and logic work of a computer. The microprocessor was made to be used in calculators, not computers. It led, however, to the invention of personal computers, or microcomputers.

It wasn't until the 1970's that people began buying computers for personal use. One of the earliest personal computers was the Altair 8800 computer kit. In 1975, you could purchase this kit and put it together to make your own personal computer. In 1977, the Apple II was sold to the public and in 1981 IBM entered the PC (personal computer) market.

Today we have all heard of Intel and its Pentium processors and now we know how it all got started. The computers of the next generation will have millions upon millions of transistors on one chip and will perform over a billion calculations in a single second. There is no end in sight for the computer movement.

  

History of computer

Necessity is the mother iof the invention.The saying holds true for computers too.Computers were invented because of man’s search for last and accurate calculating devices.Computer  was not invented by a person in a particular time.It is the result of the gradual development of calculating technology, in this we discuss the development of different and machines which led to the development of modern computers.

Abacus

Approximately 4,000 years ago, the Chinese invented the Abacus. It was the first machine used for counting and calculating. It is made of a wooden frame, metal rods, and wooden beads. It takes a great deal of time and practice to learn how to master the use of an abacus. An abacus is a person who is very experienced in using an abacus. Today, the abacus is still used widely in China and other Asian countries to count and calculate, just as we use calculators.

Each bead has a specific value. Reading from right to left, the beads in the first column are worth 1, in the second column the beads are worth 10, in the third column the beads are worth 100, etc. Addition, subtraction, multiplication, and division are performed by moving the appropriate beads to the middle of the abacus.

John Napier & Napier's Bones

In the early 17th century, John Napier, a Scottish mathematician, invented another calculating tool. It used marked strips of wood or bone, side by side, to multiply and divide. This tool became known as "Napier's Bones."

The Pascaline

The Pascaline was a wooden box that could only add and subtract by means of a series of gears and wheels. When each wheel rotated one revolution, it would then turn the neighboring wheel. On top of the wheels were a series of windows through which the totals could be read. About 50 models were constructed and were made of wood, ivory, ebony, and copper.

1673-Wilhelm Gottfried Liebniz and The Stepped Reckoner

In 1673, German inventor Gottfried Liebniz perfected the Liebniz Calculator. Liebniz entered a university at fifteen years of age and received his bachelor's degree at seventeen. This machine is sometimes called The Stepped Reckoner. The Liebniz was also a calculating machine, but much superior to that of the Pascaline. It could do more than just add and subtract. The Liebniz Calculator could also multiply, divide, and find square roots of numbers. It too was mechanical and worked by hand. A crank was added to speed up the work of this calculator. It was used by mathematicians and bookkeepers.

 

Liebniz's Calculator

Mr. Liebniz believed that it did not make sense fo men to spend hours and hours doing mathematical calculations when he could invent a machine that would work much faster. Would you rather add a long list of numbers with a pencil and paper or use a calculator?

1801-Joseph-Marie Jacquard & the Jacquard's Loom

Jacquard's Loom

In 1801, Jacquard invented the Jacquard loom. It was a weaving machine that was controlled by punched cards. While the loom was being pumped, cards with holes in them were attached together in a pattern through which strings of thread were automatically fed. These cards would feed the right pieces of thread into the loom to make a beautiful cloth.

His invention scared other weavers because it made cloth faster and better than they could by hand. As a result, Jacquard's house and loom were burned down.

This violent act did not discourage Jacquard, for he built another loom. Weavers today still use the Jacquard Loom.

In the years to follow, variations on jacquard's punched cards would find a variety of uses, including representing the music to be played by automated pianos and the storing of programs for computers.

Charles Babbage & his Engines

In the early 1820s, an English mathematician by the name charles Babbage, designed a computing machine called the Difference Engine. This machine was to be used in the calculating and printing of simple math tables. In the 1830s, he designed a second computing machine called the Analytical Engine. This machine was to be used in calculating complicated problems by following a set of instructions.

Analytical Engine

The Analytical Engine was a mechanical computer that can solve any mathematical problem. It uses punch-cards similar to those used by the Jacquard loom and can perform simple conditional operations.

 

Difference Engine

However, neither of these machines were ever finished because the technology at the time was not advanced enough, and both of his projects lacked financial funding. The computing machines made in the 1900s, and even those today are based on the designs of the Difference Engine and the Analytical Engine. This is why charles Babbage is known as the "Father of Computers."

Augusta Ada Byron, Countess of Lovelace

Much of what we know about Babbage and his machine comes from the papers of Augusta Ada Byron, countess of Lovelace and daughter of the poet Lord Byron. lady Lovelace was a genius in math. curious about Babbage's work, she translated an article about the analytical engine from French to English. she added some important notes of her own about how the machine should work. She outlines the fundamentals of computer programming, including data analysis, looping and memory addressing.

Lady Lovelace also helped Babbage with programs for the Analytical Engine. Many of her ideas are like those used in today's computer programs. Sadly, like Babbage, lady Lovelace never lived to see her ideas used. She died at age 36 while Babbage was still working on the Analytical Engine. Her work has long outlived her, however. She is now called "the first programmer," and a programming language used chiefly by the U.S. government was named Ada in her honor.

Electro-mechanical Machines

1890-Herman Hollerith & his Tabulating Machine

 An American inventor by the name of Herman Hollerith wanted to speed up the work involved in taking the government census. In 1890, 50 years after charles Babbage's death, Hollerith invented a machine called the tabulating Machine, using notes that were left by Babbage.

Prior to this invention it took nearly eight years to count everyone in the United States and add up all the information about where people lived, their ages, and what their jobs were. The Tabulating Machine used punched cards to record and sort data or information. Each hole punched meant something. If a hole had been punched, a pin would pass through it to make an electrical contact with mercury in a cup below. This turned motors that moved numbers that counted. Approximately 65 cards could be passed through this computer in a minute, and in 1890 it took only 2.5 years to complete the U.S. Census.

Hollerith did not stop with this one invention. He began a company by the name of the Tabulating Machine Company. Eventually this company changed its name to International Business Machines (IBM)--one of the largest computer companies in the world.

 

1930-Vannevar Bush and the Differential Analyzer

In 1930, Vannevar Bush introduced the first electronic "computer" in the United States. It was an analog device. That is, it could measure quantities that changed continuously, such as temperature and air pressure. It used vacuum tubes to switch electrical signals that performed calculations. Bush's machine could do 25 calculations in a few minutes. To show the results, a pen fixed above a drawing board was used to draw a curve on a graph.

The Differential Analyzer weighed 100 tons, used 2000 vacuum tubes, thousands of relays, 150 motors, and approximately 200 miles of wire.

Double-click to see simulation

 

1944-Howard Aiken and the Mark I

The next major invention in the history of computing began in 1937. In that year Howard Aiken outlined a plan for a machine that could perform math problems involving very large numbers. Because it handled distinct amounts or numbers, it was a digital (rather than analog) device.

In 1944, IBM paid engineers to build Aiken's machine. Called the Mark I, it was made up of 78 adding machines and desk calculators that were connected by almost 500 miles of wires. In one second, the Mark I could add three eight-digit numbers; for example, 12,345,678 plus 90,123,456 plus 78,901,234. It could print out its results on punched cards or on an electric typewriter.

The machine had some serious disadvantages, however; it was enormous--51 feet long and 8 feet high. Its 3,000 electrical switches made a terrible racket as they kicked on and off. The Mark I was expensive and complicated to build. After all, it had one million parts and weighed approximately 5 tons!

Grace Hopper

One of the primary programmers for the Mark I was a woman, Grace Hopper. Hopper found the first computer "bug": a dead moth that had gotten into the Mark II and whose wings were blocking the reading of the holes in the paper tape. The word "bug" had been used to describe a defect since at least 1889 but Hopper is credited with coining the word "debugging" to describe the work to eliminate program faults.

Introduction to computer

The word "computer" comes from "compute", which means,"to calculate".People usually consider a computer  to be a calculating device that can perform arithmetic operations at high speed.an computer is an electronic device, which posses raw data (unprocessed facts) fed to it and gives out the meaningful information through its output device after there input data is processed by its processor and can store data in its memory.a computer consists of following components-input device though which data are fed to it,central processing unip(CPU) where the ata get processed,memory to hold,at least temporarily,data and programs,the output device that lets you see what the computer has accomplished and mass storage device which allows a computer permanently store large amounts of data.

Characteristics of a computer-

a.     Speed

          The time take to perform any task by computer is called speed of computer                                                                 as you know computer can work very fast. It takes only few seconds for    calculations that we take hours to complete. The speed of computer is measured in MIPS (Millions Inch per Seconds).

b.     Accuracy 

Computer is the accurate machine. It can perform large number of takes without errors but if we feed wrong data to the computer it returns the same wrong output or wrong information. If the computer hardware parts are able to work and given input is correct the computer can give 100% accurate result. The process to giving correct result and wrong result is called GIGO (Garbage In garbage Out).

c.      Diligence 

The capacity of performing repetitive task without getting tired is called diligence capacity of computer. A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error.

d.     Versatility

The capacity of performing more than one work is called versatility of computer. It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips, office work, mathematical calculation, word processing etc.

e.      Storage

Computer has mass storage section where we can store large volume of data for future work. Such data are easily accessible when needed. Magnetic disk, magnetic tape and optical disk are used as the mass storage devices. The storage capacity is measured in terms of KB, MB, GB, TB, PB, EB etc...

f.       Automatic

Once we give the appropriate instruction, a computer can perform the operations automatically. Like

computer can do addition, subtraction, division and multiplication etc. Computer can automatically compare values also. It also does copying value from one memory location to other locations.

g.     Power of Remembering 

Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.

h.     Word Length

A digital computer operates on binary digits-0 and 1. It manipulate data only in terms of 0 and 1. A binary digit is called a bit. The number of bits that computer can process at a time in parallel is called its word length. Word lengths computer are varies such as 8, 16, 32, 64 bits. It is the measurement of the computing power of computer.

i.       Processing

Computer can process large volume of data in great speed. There are different types of operation during processing such as input / output operation logic operation comparison operation text manipulation operation.