Introduction

The history of computer development is often discussed with reference to the different generations of computing devices. In computer terminology, the word generation is described as a stage of technological development or innovation. A major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices, characterises each generation of computer. According to the technology used, there are five generations of computers, which are discussed in the following sections.Over the years, computers have evolved through different generations, each characterized by significant innovations and improvements. In this blog, we will embark on a fascinating journey through the generations of computers, from the pioneering days of ENIAC to the era of Artificial Intelligence (AI).

Some Early Computers

Before discussing various generations of computers, let us discuss some well-known computers of the past, which are considered to be the predecessors of modern computers.

Mainframes and Minicomputers

This was the era during which computing began and mainframe computers were born. As the heart of early computing, these machines were big enough for people to walk in and supported scientific, military, governmental and business needs. IBM’s System/360, announced in the 19-60s was so revolutionary due to the fact that they provided a wide selection of compatible models. At the same time, minicomputers opened up because they were cheaper and smaller than mainframes with applications for particular uses.

Microprocessors and Personal Computers

The introduction of microprocessers in the 1970s required computing history to change its course. This was also the first microprocessor in the world, when Intel released its 4004 to market in 1971 causing widespread personal computers. Such computers were Altair 8800, Apple I and II as well as IBM PC pioneers of personal computer industry. Apple Macintosh which was used in the 1980s delivered a revolutionary way of interacting with computers thanks to its graphical user interface (GUI).

The Internet and Web

The invention of the internet in the late 20 th century marked a tremendous transformation in computing. In 1989, Tim Berners-Lee created the World Wide Web which resulted into a standardized sharing of information as well as the introduction of web browsing software like Netscape Navigator and Internet Explorer E-commerce, online communication and information transmission became key elements of the contemporary life.

The new century has seen the expansion of mobile computing. As personal computing is concerned, smartphones and tablets were led by the Apple’s iPhone and iPad to revolutionize. Mobile apps, app stores, and responsive web design became three inherent elements of the digital space. Mobile devices enable us to have a powerful computer directly in our hands, allowing for modes of communication and productivity unheard of before.

Cloud Computing and Big Data

Cloud computing has made significant changes in the way data is hosted, processed as well as accessed. Solutions such as AWS, Azure, and the Google Cloud have proven to be scalable while cutting down on unnecessary expenses for businesses and individuals. The age of big data, characterized by large databases and sophisticated analytics can go a long way in helping us turn vast amount of information to profound insights.

Artificial Intelligence and Machine Learning

AI and ML are key contributors to the modern computing era. Recent trends in deep learning, neural networks, and natural language processing have led to groundbreaking AI applications. The numerous AI and ML applications employed by virtual assistants like Siri and Alexa, recommendation algorithms, autonomous vehicles only go to show how powerful these techniques really are.

Quantum Computing

Quantum computing is the state-of-the-art of computational mechanisms. They capitalize on the distinctive features quantum mechanics to compute virtually impossible with regular ones; they use qubits. While some there have been significant developments in quantum computing research by companies, such as IBM and Google that are showing enormous potential for solving problems with a high level of complexity such as cryptography, materials science, and drug discovery.

The Future of Computing

As we move forward, developments in computing continue to shape our world. The integration of computing into everyday objects, known as the Internet of Things (IoT), promises to connect our homes, cities, and industries in unprecedented ways. Additionally, as we explore quantum computing, artificial intelligence, and the potential for truly immersive virtual reality, the possibilities are limitless.

MARK-I Computer

From the year 1937 to 1944, an American mathematician, Howard Aiken, under the sponsorship of IBM, developed MARK-I. It was essentially a serial collection of electromechanical calculators and had many similarities to Babbage’s analytical machine. This electronic calculating machine used relays and electromagnetic components to replace mechanical components. MARK-I was capable of performing addition, subtraction, division, multiplication, and table reference. However, it was extremely slow, noisy and bulky (approximately 50 feet long, 8 feet high, and weighed 5 tons).

ABC Computer

In 1939, John Vincent Atansoft and Clifford Berry formulated the idea of using the binary number system to simplify the construction of an electronic calculator. By the end of 1939, they built a first electronic computer named as ABC (Atansoft Berry Computer). It is considered as the first computing machine which introduced the idea of binary arithmetic, regenerative memory, and logic circuits. This computer used electronic vacuum tubes and the circuitry was based on George Boole’s Boolean algebra.

COLOSSUS

In 1944, British mathematician Alan Mathison, along with some colleagues, created a computer named Colossus, which comprised 1800 vacuum tubes. It was one of the world’s earliest working programmable electronic digital computers. Colossus was a special-purpose machine that suited a narrow range of tasks (for example, it was not capable of performing decimal multiplications). Although Colossus was built as a special-purpose computer, it proved flexible enough to be programmed to execute a variety of different routines.

ENIAC

In 1946, John Eckert and John Mauchly of the Moore School of Engineering at the University of Pennsylvania developed ENIAC or Electronic Numerical Integrator and Calculator. Like the ABC, this computer used electronic vacuum tubes to make the internal parts of the computer. It embodied almost all the components and concepts of today’s high-speed, electronic digital computers. This machine could discriminate the sign of a number, compare quantities for equality, add, subtract, multiply, divide, and extract square roots. ENIAC consisted of 18000 vacuum tubes, required around 160 KW of electricity and weighed nearly 30 tons. It could compute at speeds 1000 times that of Mark-I but had a limited amount of space to store and manipulate information.

EDVAC

John Eckert and John Mauchly also proposed the development of Electronic Discrete Variable Automatic Computer (EDVAC). Although, the conceptual design for EDVAC was completed by 1946, it came into existence in 1949. The EDVAC was the first electronic computer to use the stored program concept introduced by John Von Neumann. It also had the capability of conditional transfer of control, that is, the computer could be stopped at any time and then resumed. EDVAC contained approximately 4000 vacuum tubes and 10000 crystal diodes.

EDSAC

EDSAC, or Electronic Delay Storage Automatic Calculator, was also based on John Von Neumann’s stored program concept. The work began on EDSAC in 1946 at the Cambridge University by a team headed by Maurice Wilkes. In 1949, the first successful program was run on this machine. It used mercury delay lines for memory, and vacuum tubes for logic. EDSAC had 3000 vacuum valves arranged on 12 racks and used tubes filled with mercury for memory. It could carry out only 650 instructions per second. A program was fed into the machine via a sequence of holes punched into a paper tape. The machine occupied a room, which measured 5 metres by 4 metres.

UNIVAC

UNIVAC, or Universal Automatic Computer, was the first commercially available electronic computer. It was also the first general-purpose computer, which was designed to handle both numeric and textual information. The Eckert-Mauchly Corporation manufactured it in 1951 and its implementation marked the real beginning of the computer era. UNIVAC could compute at a speed of 120-3600 microseconds. Magnetic tapes were used as input and output mediums at a speed of around 13000 characters per second. The machine was 25 feet by 50 feet in length, contained 5600 tubes, 18000 crystal diodes, and 300 relays. The UNIVAC was used for general-purpose computing with large amounts of input and output.

IBM 650 (1954)

The IBM 650 was one of the first mass-produced computers. It used punched card input/output and magnetic drum memory. It found widespread use in universities and businesses.

IBM 1401 (1959)

Another early IBM computer, the 1401, was a popular choice for business data processing. It featured decimal arithmetic and played a crucial role in the growth of business computing.

PDP-1 (Programmed Data Processor-1, 1959)

Developed by Digital Equipment Corporation (DEC), the PDP-1 was a minicomputer that had a significant impact on early interactive computing. It was used for various applications, including early video games.

IBM System/360 (1964)

The System/360 was a historic series of mainframe computers and it had an interoperability between different types of models. It shaped standardization in the computer industry profoundly.

The early computers were big and costly machines which were mostly used for scientific purposes and business activities. Their efforts created a firm ground for the quick innovations in computing technology that would be witnessed in subsequent decades.

Brief history of computers generation

First Generation (1940–56): Vacuum Tubes

First generation computers were vacuum tubes/thermionic valve based machines. These computers used vacuum tubes for circuitry and magnetic drums for memory. A magnetic drum is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Input was based on punched cards and paper tape and output was displayed in the form of printouts.

First generation computers relied on binary-coded language (language of 0s and 1s) to perform operations and were able to solve only one problem at a time. Each machine was fed with different binary codes and hence were difficult to program. This resulted in lack of versatility and speed. In addition, to run on different types of computers, instructions must be rewritten or recompiled.

Examples: ENIAC, EDVAC, and UNIVAC.

Characteristics of First Generation Computers

These computers were based on vacuum tube technology.
These were the fastest computing devices of their times (computation time was in milliseconds).
These computers were very large, and required a lot of space for installation.
Since thousands of vacuum tubes were used, they generated a large amount of heat. Therefore, air conditioning was essential.
These were non-portable and very slow equipments.
They lacked in versatility and speed.
They were very expensive to operate and used a large amount of electricity.
These machines were unreliable and prone to frequent hardware failures.Hence, constant maintenance was required.
Since machine language was used, these computers were difficult to program and use.
Each individual component had to be assembled manually. Hence,commercial appeal of these computers was poor.

Second Generation (1956–63): Transistors

Second generation computers used transistors, which were superior to vacuum tubes. A transistor is made up of semiconductor material like germanium and silicon. It usually had three leads (see above Figure) and performed electrical functions such as voltage, current or power amplification with low power requirements. Since transistor is a small device, the physical size of computers was greatly reduced. Computers became smaller, faster,cheaper, energy-efficient and more reliable than their predecessors.

In second generation computers, magnetic cores were used as primary memory and magnetic disks as secondary storage devices. However, they still relied on punched cards for input and printouts for output.

One of the major developments of this generation includes the progress from machine language to assembly language. Assembly language used mnemonics (abbreviations) for instructions rather than numbers, for example, ADD for addition and MULT for multiplication. As a result, programming became less cumbersome. Early high-level programming languages such as COBOL and FORTRAN also came into existence in this period.

Examples: PDP-8, IBM 1401 and IBM 7090.

Characteristics of Second Generation Computers

These machines were based on transistor technology.
These were smaller as compared to the first generation computers.
The computational time of these computers was reduced to microseconds from milliseconds.
These were more reliable and less prone to hardware failure. Hence,such computers required less frequent maintenance.
These were more portable and generated less amount of heat.
Assembly language was used to program computers. Hence, programming became more time-efficient and less cumbersome.
Second generation computers still required air conditioning.
Manual assembly of individual components into a functioning unit was still required.

Third Generation (1964–Early 1970s): Integrated Circuits

The development of the integrated circuit was the trait of the third generation computers. Also called an IC, an integrated circuit consists of a single chip (usually silicon) with many components such as transistors and resistors fabricated on it. Integrated circuits replaced several individually wired transistors. This development made computers smaller in size, reliable, and efficient.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with operating system. This allowed the device to run many different applications at one time with a central program that monitored the memory. For the first time, computers became accessible to mass audience because they were smaller and cheaper than their predecessors.

Examples: NCR 395 and B6500.

Characteristics of Third Generation Computers

These computers were based on integrated circuit (IC) technology.
They were able to reduce computational time from microseconds to nanoseconds.
They were easily portable and more reliable than the second generation.
These devices consumed less power and generated less heat. In some cases, air conditioning was still required.
The size of these computers was smaller as compared to previous computers.
Since hardware rarely failed, the maintenance cost was quite low.
Extensive use of high-level languages became possible.
Manual assembling of individual components was not required, so it reduced the large requirement of labour and cost. However, highly sophisticated technologies were required for the manufacture of IC chips.
Commercial production became easier and cheaper.

Fourth Generation (Early 1970s–Till Date): Microprocessor

The fourth generation is an extension of third generation technology.Although, the technology of this generation was still based on the integrated circuit, these have been made readily available to us because of the development of the microprocessor (circuits containing millions of transistors). The Intel 4004 chip, which was developed in 1971, took the integrated circuit one step further by locating all the components of a computer (central processing unit, memory, and input and output controls) on a minuscule chip. A microprocessor is built onto a single piece of silicon,known as chip. It is about 0.5 cm along one side and no more than 0.05 cm thick.

The fourth generation computers led to an era of Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) technology. LSI technology allowed thousands of transistors to be constructed on one small slice of silicon material whereas VLSI squeezed hundreds of thousands of components on to a single chip. Ultra-large scale integration (ULSI) increased that number into millions. This way computers became smaller and cheaper than ever before.

The fourth generation computers became more powerful, compact, reliable,and affordable. As a result, it gave rise to the personal computer (PC) revolution. During this period, magnetic core memories were substituted by semiconductor memories, which resulted in faster random access main memories. Moreover, secondary memories such as hard disks became economical,smaller, and bigger in capacity. The other significant development of this era was that these computers could be linked together to form networks,which eventually led to the development of the Internet. This generation also saw the development of the GUIs (Graphical User Interfaces), mouse, and handheld devices. Despite many advantages, this generation required complex and sophisticated technology for the manufacturing of CPU and other components.

Examples: Apple II, Altair 8800, and CRAY-1.

Characteristics of Fourth Generation Computers

Fourth generation computers are microprocessor-based systems.
These computers are very small.
Fourth generation computers are the cheapest among all the other generations.
They are portable and quite reliable.
These machines generate negligible amount of heat, hence they do not require air conditioning.
Hardware failure is negligible, so minimum maintenance is required.
The production cost is very low.
GUI and pointing devices enable users to learn to use the computer quickly.
Interconnection of computers leads to better communication and resource sharing.

Fifth Generation (Present and Beyond): Artificial Intelligence

The dream of creating a human-like computer that would be capable of reasoning and reaching a decision through a series of “what-if-then” analyses has existed since the beginning of computer technology. Such a computer would learn from its mistakes and possess the skill of experts.These are the objectives for creating the fifth generation of computers.The starting point for the fifth generation of computers has been set in the early 1990s. The process of developing fifth generation of computers is still in the development stage. However, the expert system concept is already in use. The expert system is defined as a computer information system that attempts to mimic the thought process and reasoning of experts in specific areas. Three characteristics can be identified with the fifth generation computers, which are:

Mega Chips: Fifth generation computers will use Super Large Scale Integrated (SLSI) chips, which will result in the production of microprocessor having millions of electronic components on a single chip. In order to store instructions and information, fifth generation computers require a great amount of storage capacity. Mega chips may enable the computer to approximate the memory capacity of the human mind.
Parallel Processing: Most computers today access and execute only one instruction at a time. This is called serial processing. However, a computer using parallel processing accesses several instructions at once and works on them at the same time through the use of multiple central processing units.
Artificial Intelligence (AI): It refers to a series of related technologies that tries to simulate and reproduce human behaviour,including thinking, speaking and reasoning. AI comprises a group of related technologies: expert systems (ES), natural language processing (NLP), speech recognition, vision recognition, and robotics.

Conclusion

The evolution of computers through different generations has been a remarkable journey that has transformed the way we live and work. From the pioneering days of ENIAC to the era of AI and modern computing, each generation has brought unique innovations and challenges. As we continue to push the boundaries of technology, we can only imagine what the future holds for the next generation of computers and the impact they will have on our world.

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