Generation of Computers
👉Generation of computers provides a framework for the growth of the computer industry based on developed technologies. At first, it was used to distinguish between hardware technologies but was later extended to include both hardware and software technologies.
✔ There are five computer generations known until today:-
1. First Generation (1942-1955)
The early computers of their time were manufactured using vacuum tubes as an electronic switching devices.
A vacuum tube was a fragile glass device using filament as a source of electronics and could control and amplify electronic signals. It was the only high-speed electronic switching device available in those days. These vacuum tube computers could perform computations in milliseconds and be known as first-generation computers.
Most of the first-generation computers worked on storing program instructions and data in a computer’s memory so that they could automatically execute a program without human intervention.
The memory of these computers used electromagnetic relays, and users fed all data and instructions into the system using punched cards.
Programmers wrote instructions in the machine and assembly language because of the lack of high-level programming languages in those days. Since machine and assembly languages are difficult to work with, only a few specialists understood how to program these early computers.
Characteristic features of first-generation computers are as follows:-
📍Fastest calculating devices of their time.
📍Too bulky in size requiring large rooms for installation.
📍The rooms/areas in which these computers were located had to be appropriately air-conditioned as they used thousands of vacuum tubes that emitted a large amount of heat and burnt out frequently.
📍High Power Consumption – Each vacuum tube consumed about half a watt of power. Since a computer typically used more than 10,000 vacuum tubes, the power consumption of these computers was very high.
📍Frequent Hardware Failures – As vacuum tubes used filaments, they had a limited life. Because a computer used thousands of vacuum tubes, these computers were prone to frequent hardware failures.
📍Require Constant Maintenance – Due to the low mean time between failures, these computers required constant maintenance.
📍Difficult/Costly to Produce Commercially – In these computers, thousands of individual components were assembled manually into electronic circuits. Hence, commercial production of these computers was difficult and costly.
📍Limited Commercial Use – Since these computers were difficult to program and use, they had limited commercial use.
Some representative systems:- ENIAC, EDVAC, EDSAC, UNIVAC I, IBM 701, IBM 650
2. Second Generation (1955-1964)
John Bardeen, William Shockley, and Walter Brattain invented a new electronic switching device called the transistor at bell laboratories in 1947.
Transistors soon proved to be a better electronic switching device than vacuum tubes due to their following properties:-
(i) Rugged and Easy to Handle – They were more rugged and easier to handle than tubes since they were made of germanium semiconductor rather than glass.
(ii) Highly Reliable – Since they had no parts like a filament that could burn out, they are highly reliable compared to tubes.
(iii) Faster than tubes – They could switch much faster (almost ten times faster) than tubes. Hence, switching circuits made of transistors could operate much faster than their counterparts made of tubes.
(iv) Consume Less Power – Consumed almost 1/10 the power consumed by a tube and was much smaller than a tube.
(v) Less Expensive – They were less expensive to produce and dissipated much less heat than vacuum tubes.
Second-generation computers were manufactured using transistors. They were more robust, reliable, less expensive, smaller, and more excellent to operate than the first-generation computers.
The second generation also experienced the change in storage technology. A memory of second-generation computers was composed of magnetic cores.
Magnetic cores are small rings made of ferrite that can be magnetized in either clockwise or anticlockwise directions. Large Random-Access Memory (having a storage capacity of a few tens of KB) had several magnetic cores strung on a mesh of wires.
In 1957, researchers introduced Magnetic tape as a faster and more convenient secondary storage medium.
Later, magnetic disk storage was also developed, and magnetic disk and Magnetic tape were the main secondary storage media used in second-generation computers. Users Still used punched cards widely for preparing and feeding programs and data to a computer.
On the software front, high-level programming languages like (FORTRAN, COBOL, ALGOL, and SNOBOL) and batch operating systems emerged during the second generation.
High-level programming languages made second-generation computers easier to program and use than first-generation computers.
Introduction a batch operating system helped reduce human intervention while processing multiple jobs, resulting in faster processing, enhanced throughput, and more effortless operation of second-generation computers.
In addition to specific computations, business and industry users used second-generation computers increasingly for commercial data processing applications like payroll, inventory control, marketing, and production planning.
The ease of use of second-generation computers gave birth to a new profession of programmers and system analysts in computing that is more oriented towards usage rather than the design of computers. This triggered the introduction of Computer Science related courses in several colleges and Universities.
Characteristic features of second-generation computers are as follows:-
📍Faster – They were more than ten times faster than the first-generation computers.
📍Smaller – They were smaller than first-generation computers and required smaller space.
📍Consume Less Power – They consume less power and dissipate less heat than first-generation computers. The rooms/areas in which the second-generation computers were located still required to be properly air-conditioned.
📍More Reliable – They were more reliable and less prone to hardware failures than first-generation computers.
📍Larger Memory Storage – They had faster and larger primary and secondary storage as compared to the first-generation computers.
📍Easier to Program – They were easier to program and use than the first-generation computers. Hence, they had wider commercial use.
📍Costly for commercial Use – In these computers, thousands of individual transistors had to be assembled manually by hand into electronic circuits making commercial production of these computers difficult and costly.
Some representative systems:- Honeywell 400, IBM 7030, CDC 1604, UNIVAC LARC
3. Third Generation (1964-1975)
In 1958, Jack St. Clair Kilby and Robert Noyce invented the first Integrated circuit.
Integrated circuits (called ICs) are circuits consisting of several electronic components like transistors, resistors, and capacitors grown on a single chip of silicon eliminating wired interconnection between components.
IC technology was also known as “microelectronics” technology because it made it possible to integrate a larger number of circuit components into a very small (less than 5 mm square) surface of silicon, known as a “Chip”.
Initially, the integrated circuits contained only about 10 to 20 components. This technology was named Small-Scale Integration (SSI). Later with the advancement in technology for manufacturing ICs, it became possible to integrate up to about a hundred components on a single chip. This technology was known as medium-scale integration (MSI).
Third-generation computers were manufactured using ICs. Earlier ones used SSI technology and later ones used MSI technology.
Integrated circuits were smaller, less expensive to produce, more rugged and reliable, faster in operation, dissipated less heat, and consumed less power than circuits built by wiring electronic components manually. Hence, third-generation computers were more powerful, more reliable, less expensive, smaller, and cooler to operate than second-generation computers.
Parallel advancements in storage technologies allowed the construction of larger magnetic core-based Random-Access Memory as well as the largest capacity magnetic disks and tapes. Hence, third-generation computers typically had a few megabytes (less than 5 MB) of main memory and magnetic disks capable of storing a few tens of megabytes of data per disk drive.
On the software front, standardization of high-level programming languages, time-sharing operating systems, unbundling of software from hardware, and the creation of an independent Software Industry happened during the third generation.
FORTRAN and COBOL were the most popular high-level programming languages in those days. Some more high-level programming languages were introduced during the third generation period. Notable among these were PL/1, PASCAL, and BASIC.
During this period, IBM introduced its System 360 as a family of computers with backward compatibility as there are different sizes of mainframe systems based on the same machine language. This enabled businesses to upgrade their computers without incurring the costs of replacing peripheral equipment and modifying programs to run on new systems.
Development and introduction of minicomputers also took place during the third generation.
Characteristic features of third-generation computers are as follows:-
📍More Powerful – They were more powerful than second-generation computers. They could perform about 1 million instructions per second.
📍Smaller in Size – They were smaller than second-generation computers requiring a smaller space.
📍Consume Less Power – They consumed less power and dissipated less heat than second-generation computers. The rooms/areas in which third-generation computers were located still required to be properly air-conditioned.
📍More Reliable – They were more reliable and less prone to hardware failures than second-generation computers requiring lower maintenance costs.
📍Large Storage – They had faster and larger primary and secondary storage as compared to second-generation computers.
📍Suitable for Scientific and Commercial Purposes – They were general-purpose machines suitable for both scientific and commercial applications.
📍Reduced Labour and Cost – Their manufacturing did not require manual assembly of individual components into electronic circuits resulting in reduced human labor and cost involved at the assembly stage. Hence, commercial production of these systems was easier and cheaper. However, highly sophisticated technology and an expensive setup were required for the manufacture of IC chips.
📍Timesharing operating system allowed interactive usage and simultaneous use of these systems by multiple users. It drastically improves the productivity of programmers cutting down the time and cost of program development several-fold. It also made online systems feasible resulting in the usage of these systems for new online applications.
Some representative Systems :- IBM 360/370, PDP-8, PDP-11, CDC 6600
4. Fourth Generation (1975-1989)
The average number of electronic components packed on a silicon chip doubled each year after 1965. This process soon led to the era of large-scale integration (LSI) when it was possible to integrate over 30,000 electronic components on a single chip, followed by very large-scale integration (VLSI) when it was possible to integrate about one million electronic components on a single chip. This process led to the dramatic development – the creation of a microprocessor.
A microprocessor contains all circuits needed to perform arithmetic logic and control functions, the core activities of all computers, on a single chip. Hence, it became possible to build a complete computer with a microprocessor, a few additional primary storage chips, and other support circuitry.
It started a new social revolution – the personal computer revolution. Overnight computers became incredibly compact. They became inexpensive to make and suddenly it became possible for many to own a computer.
During the fourth generation, semiconductor memories replaced magnetic core memories resulting in large Random Access Memories with very fast access time. Hard disks became cheaper, smaller, and larger in capacity. In addition to magnetic tapes, floppy disks became popular as a portable medium for porting programs and data from one computer system to another.
Significant advancements also took place during the fourth generation in the area of large-scale computer systems. High-speed computer networking also developed during the fourth generation. This enabled interconnection of multiple computers for communication and sharing of data among them. Local area networks (LANs) and wide-area networks (WANs) became popular for connecting computers located at distances.
On the software front, several new developments emerge to match the new technologies of the fourth generation. Vendors developed several new operating systems like MS-DOS, MS Windows, and Apple’s propriety Mac OS. During the fourth generation, the Unix operating system also became very popular for use on large-scale systems.
Some other software technologies that became popular during the first generation are C programming language, object-oriented software design, and object-oriented programming like C++.
Characteristic features of fourth-generation computers are as follows:-
📍Smaller and Cheaper – PCs were smaller and cheaper than mainframes or minicomputers of the third generation.
📍No Air Condition required for PCs – Although the fourth-generation mainframes and supercomputers required proper air conditioning of the rooms/areas in which they were located, no air conditioning was required for PCs.
📍Consume Less Power – They consumed less power than third-generation computers.
📍More Reliable – They were more reliable and less prone to hardware failures than third-generation computers requiring negligible maintenance costs.
📍Large Storage – They had faster and larger primary and secondary storage as compared to third-generation computers.
📍Easier Commercial Production – Their manufacturing did not require manual assembly of individual components into electronics circuits resulting in reduced human labor and cost involved at the assembly stage. Hence commercial production of these systems was easier and cheaper. However, highly sophisticated technology and an expensive setup were required for manufacturing LSI and VLSI chips.
📍Sharing of Resources – A network of computers enabled sharing of resources like disks, printers, etc. among multiple computers and their users. They also enabled several new types of applications involving interaction among computer users at geographically distant locations.
📍Add-on Enabled – In addition to unbundled software, these systems also used add-on hardware features that allow users to invest only in the hardware configuration and software of their need and value.
📍Affordability – PCs of the fourth generation made computers affordable even for individuals for their personal use at home.
📍They were general-purpose machines.
📍The use of standard high-level programming languages allowed programs written for one computer to be easily ported to and executed on another computer.
📍Graphical User Interface (GUI) enabled new users to quickly learn how to use computers. PC-based applications made PCs a powerful tool for both office and home usage.
📍Supercomputers of the fourth generation enabled parallel processing of different parts of an application on a large number of processors used in these systems. This in turn enabled the running of time-consuming applications much faster.
Some Representative Systems:- IBM PC and its clones, Apple II, TRS-80, VAX 9000, CRAY-I, CRAY-2, CRAY-XMP.
5. Fifth Generation (1989-Present)
The trend of further miniaturization of electronic components, a dramatic increase in power of microprocessor chips, and an increase in the capacity of main memory and hard disk continued during the fifth generation.
VLSI technology became ULSI (Ultra-Large-Scale Integration) Technology in the fifth generation resulting in the production of microprocessor chips having 10 million electronic components. In fact, the speed of microprocessors and the size of the main memory and hard disk doubled almost every 18 months.
As a result, many features found in the CPUs of large mainframe systems of third and fourth-generation systems became part of microprocessor architecture in the fifth generation.
Processor manufacturers started building multi-core processor chips instead of increasingly powerful single-core processing chips. The multicore chips improve overall performance by handling more work in parallel.
Due to this fast pace of advancement in computer technology, we see more compact and more powerful computers being introduced almost every year at more or less the same price or even cheaper. Powerful desktop PCs and workstations, powerful servers, powerful supercomputers, and handheld computers are examples of fifth-generation computers.
Storage technology also advanced making large main memory and disk storage available in newly introduced systems.
In the area of large-scale systems, fifth-generation saw the emergence of more powerful supercomputers based on parallel processing technology. They used multiple processors and were of two types – shared memory and distributed memory parallel computers.
During the fifth generation, the Internet emerged with associated technologies and applications. It made it possible for computer users sitting across the globe to communicate with each other within minutes by use of electronic mail facility. A vast ocean of information became readily available to computer users through the World Wide Web (WWW).
The tremendous processing power and the massive storage capacity of fifth-generation computers also made them a very useful and powerful tool for a wide range of multimedia applications dealing with information containing text, graphics, animations, audio, and video data.
In the area of operating systems, some new concepts that gained popularity during the fifth generation include microkernels, multithreading, and multicore operating systems.
Microkernel technologies enabled designers to model and design operating systems in a modular fashion. Multithreading technology is a popular way to improve application performance through parallelism. A multi-core operating system can run multiple programs at the same time on a multicore chip with each core handling a separate program.
In the area of programming languages, concepts that gained popularity during the fifth generation are JAVA programming language, and parallel programming libraries like MPI (message passing interface) and PVM (parallel virtual machine).
Characteristic features of fifth-generation computers are as follows:-
📍Smaller and Handy PCs – Portable PCs are much smaller and handier than PCs of the fourth generation allowing users to use computing facilities even while traveling.
📍Powerful – Fifth-generation Desktop, PCs, and workstations are several times more powerful than PCs of the fifth generation.
📍No Air Conditioning Required for PCs – Although fifth-generation mainframes and supercomputers require proper air conditioning of the rooms/areas in which they are located, no air conditioning is normally required for notebook computers, Desktop PCs, and workstations.
📍Low Power Consumption – They consume less power than their predecessors do.
📍More Reliable – They are more reliable and less prone to hardware failures than their predecessors were, requiring negligible maintenance costs.
📍Higher Uptime – Many of the large-scale fifth-generation systems have a hot-plug feature that enables a failed component to be replaced with a new one without the need to shut down the system. Hence, the uptime of these systems is very high.
📍Larger Storage – They have faster and larger primary and secondary storage as compared to their predecessors.
📍Easier and Cheaper Commercial Production – Their manufacturing does not require manual assembly of individual components into electronic circuits resulting in reduced human labor and cost involved at the assembly stage. Hence, commercial production of these systems is easier and cheaper. However, highly sophisticated technology and an expensive setup are required for manufacturing ULSI chips.
📍User-Friendly Interface – More user-friendly interfaces with multimedia features make the systems easier to learn and use by anyone, including children.
📍Add-on Enabled – These systems also use the concept of unbundled software and add-on hardware allowing the users to invest only in the hardware configuration and software of their need and value.
📍Usable for All – With so many types of computers in all price ranges today, we have a computer for almost any type of user whether the user is a child or a world-famed scientist.
📍They are general-purpose machines.
📍The use of a standard high-level programming language allows programs written for one computer to be easily ported to and executed on another computer.
📍Newer and more powerful applications, including multimedia applications, make the systems more useful in every occupation.
📍The explosion in the size of the Internet coupled with Internet-based tools and applications have made these systems influence the life of even common people.
Some Representative Systems:- IBM notebooks, Pentium PCs, SUN workstations, IBM SP/2, SGI Origin 2000, PARAM Supercomputers.