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COMPUTER GENERATIONS
“Generation” in computer talk is a
step in technology. It provides a framework for the growth of computer
industry.
Originally it was used to distinguish between various hardware
technologies, but now it has been extended to include both hardware and software.
Till today, there are five computer generations which are described as
follows:
FIRST
GENERATION COMPUTERS:
During the period of 1942 to 1955 first generation of computers were developed. The
first generation computers used vacuum tubes for circuitry
and magnetic drums for memory, and were
often enormous, taking up entire rooms. The vacuum tube was developed by Lee
DeForest.
A vacuum tube was a fragile glass device generally
used to amplify a signal by controlling the
movement of electrons in an evacuated space. Most of the first generation computers worked
on the principle of storing program
instructions along with data in memory of computer so that they
could automatically execute a program without human
intervention. Memory of these
computers used
electromagnetic relays, and users fed all data and instructions into the system punched cards, which were used as input. Programmers wrote instructions in machine
and assembly languages because of lack of high level programming languages in those days.
First generation computers were very
expensive to operate and in addition to using a great deal of electricity, generated a lot of
heat, which was often the cause of malfunction. CHARACTERISTICS:
1) First generation computers were based on vacuum tubes.
2) The operating systems of the first generation
computers were very slow.
3) They were very large
in size.
4) Production of the
heat was in large amount in first generation computers.
5) Machine language
was used for programming.
6) First generation computers were unreliable.
7) They were difficult
to program and use.
EXAMPLES:
UNIVAC1, EDVAC,
EDSAC and ENIAC, IBM 701 computers are examples of first generation
computing devices.
SECOND GENERATION COMPUTERS:
During the period of 1955 to 1964 second
generation of computers were
developed. The second generation computers emerged with development of Transistors. The transistor was invented in 1947 by three scientists J.
Bardeen, H.W. Brattain and W. Shockley.
A transistor is
a small device made up of
semiconductor
material like germanium
and silicon.
Even though the Transistor were
developed in 1947
but was not widely used until the end of 50s
The transistor made the second generation
computers faster, smaller,
cheaper, more energy-efficient and more reliable than their first-generation
computers. Even though the transistor used in the computer generated enormous
amount of heat which ultimately would lead to the damage of
the computers but was far better than vacuum tubes.
Second generation computers used the low level language i.e. machine level
language and assembly language which
made the programmers
easier to specify the
instructions.
Later
on High level language programming were introduced such as COBOL
and FORTRAN.
Magnetic core was used as primary
storage.
Second generation computer has faster input /output
devices which thus brought improvement in the computer.
CHARACTERISTICS:
1)Transistors were used in
place of vacuum tubes.
2) Second
generation computer were smaller in
comparison with the first generation computers.
3) They were more than ten times faster in comparison with the first generation computers.
4) They generated less heat and were less prone to failure.
5) They took comparatively less computational
time.
6) Assembly language
was used for programming.
7) Second generation computers has faster
input/output devices.
EXAMPLES:
IBM 7030, NCR 304, IBM 650, IBM 1401, ATLAS and
Mark III are the examples of second generation
computers.
THIRD GENERATION COMPUTERS:
During the period of 1964 to 1971 Third generation computers were developed. The
third generation computers emerged with the development of IC (Integrated Circuits). The invention of the IC
was the greatest achievement done in the period of third generation of
computers. IC was invented by Robert Noyce and Jack Kilby in 1958-59.
IC is a single
component containing a number of transistors, resistors and capacitors grown on
a single chip of silicon eliminating wired interconnection between components. Transistor were based on silicon
chips, called semiconductors, which
drastically increased the speed and efficiency of computers.
IC technology was
also known as “micro electrons” technology
because it made it possible to integrate larger number of circuit components
into very small (less than 5mm square) surface of silicon, known as “chip”.
Initially the integrated circuits contained only ten to
twenty components. This technology was named
small scale integration (SSI). Later with
advancement in technology for manufacturing ICs,
it became possible to integrate up to about
hundred components on a single chip. The
technology was known as medium scale
integration (MSI).
ICs 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.
Parallel advancements in storage technologies allowed construction of
larger magnetic core based random access memory as
well as larger capacity magnetic disks and tapes.
Hence third generation computers typically had few
megabytes (less than 5 megabytes) of main memory and
magnetic disks capable of storing few tens
of megabytes of data per disk drive.
On software front
standardization of high level programming languages, timesharing
operating systems, unbundling of software from hardware, and creation of
an independent software industry happened during third generation. FORTAN and COBOL were
the most popular high level programming languages in those days. Some more high
level programming languages were introduced during third generation period. Notable
among these were PL/1,
PASCAL, and BASIC.
Keyboards and monitors developed during the period of third generation of
computers. The third generation computers interfaced with an operating system,
which allowed the device to run many different applications at one time with a
central program that monitored
the memory.
CHARACTERISTICS:
1) IC was used instead of transistors
in the third generation computers.
2) Third generation computers were smaller
in size and cheaper as compare to the second
generation computers.
3) They were fast and more reliable.
4) High level language was developed.
5) Magnetic core and solid states as main storage.
6) They were able to reduce computational
time and had low maintenance cost.
7) Input/Output devices became more
sophisticated.
EXAMPLES:
PDP-8, PDP-11, ICL 2900, IBM 360 and IBM 370 are
the examples of third generation computers
FORTH GENERATION COMPUTERS:
During 1975-1989 the
fourth generation computers were built. The fourth generation computers were
the extension of third generation technology. The fourth generation computers
emerged with development of the VLSI (Very Large
Scale Integration).With the help of
VLSI technology microprocessor came into
existence. The computers were designed by using microprocessor,
as thousands of integrated circuits were built onto a single silicon chip.
What in the first generation filled an entire room could now fit in the palm of
the hand. The fourth generation computers became more
powerful, compact, reliable and affordable.
As a result, they give rise to personal computer
(PC) revolution.
For the first time in
1981 IBM introduced its computer for the home
user and in 1984 Apple introduced the Macintosh Microprocessor.
During 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 large in capacity. In addition to
magnetic tapes, floppy disk became
popular as
a portable medium for porting programs and data form one computer system
to another.
Significant advancements also took place during fourth generation in the
area of large scale computer system. In addition to improved processing and
storage capabilities of main frame systems, the fourth generation saw the
advent of super computers
based parallel vector processing and symmetric multi processing
technologies. A supercomputer based on parallel vector processing
technology contains a small number of custom designed vector processors which
are collected to a number of high speed data access shared memory modules through
a custom designed, high bandwidth cross bar switch network. On the other hand,
a super computer based on symmetric multiprocessing technology uses commodity
microprocessors connected to a shared memory through a high speed bus or a
cross bar switch network. Primary builders of super computers of former category
included Cray Research and ETA systems, which included IBM, Silicon graphics,
and Digital Equipments Corporation.
High speed computer networking also
developed during fourth generation. This enabled interconnecting of multiple
computers for communication and sharing of data among them. Local Area Networks (LANs)
became popular for connecting computers within organizations or within a
campus. Similarly, Wide Area Networks (WANs) became popular for connecting
computers located at larger distances. This gave rise to network of computers
and distributed systems.
In the area of software for large scale computers, key
technologies that became popular included multiprocessing operating
systems and concurrent programming languages.
With multi processing operating systems, a main frame system could use multiple
processor in such a manner that the subordinate processors could manage the
user terminals and peripheral devices, allowing the main processor to
concentrate on processing the main program, improving the overall
performance.
During fourth generation, UNIX operating
systems also became popular for use on large scale systems. Additionally,
due to proliferation of computer networks, several new features where included
in existing operating systems to allow multiple computers on the same network
to communicate with each other and share resources.
Some other software
technologies that became popular during fourth generation are C programming language, object oriented software
design and object programming. C language combines features of high level programming languages with efficiency
of an assembly language. The primary objectives of object oriented software
design are to make programs generalized and to build software systems by
combining reusable pieces of program codes called objects. To facilitate object
oriented software design, several object oriented programming languages were
introduced. Out of these, C++ emerged as the most popular object oriented
language.
CHARACTERISTICS
1) The fourth generation computers have microprocessor-based
systems.
2) They are the cheapest among all the
computer generation.
3) The speed, accuracy
and reliability of the computers were
improved in fourth generation computers.
4) Many high-level languages were developed in the fourth generation such
as COBOL, FORTRAN, BASIC, PASCAL and C language.
5) A Further refinement of input/output devices was developed.
6) Networking between the systems was
developed.
EXAMPLES:
IBM 4341, DEC 10, STAR
1000, PUP 11 and
APPLE II are the examples of fourth
generation computers.
FIFTH GENERATION COMPUTERS:
Duration of fifth generation computers is 1982 –
Present. The Fifth Generation Computer
Systems project (FGCS) was an initiative by Japan's
Ministry of International Trade and Industry, begun in 1982, to create a computer using massively parallel computing/processing.
It was to be the result of a massive government/industry research project in
Japan during the 1980s. It aimed to create an
"epoch-making computer" with-supercomputer-like performance and to
provide a platform for future developments in artificial
intelligence. The use of parallel processing and superconductors is
helping to make artificial intelligence a reality. Quantum
computation and molecular and nanotechnology will radically change the face of
computers in years to come. The goal of fifth-generation computing is to
develop devices that respond to natural language
input and are capable of learning and self-organization.
Artificial intelligence is the branch of computer science
concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy
at the Massachusetts Institute of Technology. Artificial intelligence includes the following areas of
specialization:
Games Playing: programming computers to play against human oponents.
Expert Systems: programming computers to make decisions in real-life situations
(for example, some expert
systems help doctors diagnose diseases based on symptoms)
Natural Language: programming computers to understand natural human languages
Neural Networks: Systems that simulate intelligence
by attempting to reproduce the types of physical connections that occur in
animal brains
Robotics: programming computers to see and
hear and react to other sensor stimuli.
The trend of further miniaturization of electronic components, dramatic
increase in power of microprocessor chips, and increase in capacity of main
memory and hard disk continued during fifth generation.
VLSI technology became ULSI
(Ultra Large Scale Integrated) technology in fifth generation resulting
in production of microprocessor chip having ten
million electronic components. Infact, the speed of microprocessors and
the size of main memory and hard disk doubled
almost every eighteen months. As a result, many features found in the CPUs of
large main frame systems of third and fourth generation systems became part of
micro processor architecture in fifth generation. This ultimately resulted in
availability of very powerful and compact computers becoming available at cheaper rates
and death of traditional large main frame systems. Recently, processor
manufactures started building multi core processor
chips instead of increasingly powerful single core processor chip. The multi
core chips improved 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. Notable among these
are portable notebook computers that give the power of a PC to their
users even while travelling, powerful desktop PCs and work stations, powerful servers, powerful super
computers, and handheld computers.
Storage technology
also advanced making larger main memory and disk storage available in newly
introduced systems. Currently, PCs having few Gigabytes of main memory and 80-320 gigabytes of hard disk capacity are common.
Similarly workstations having 4-64 Gigabytes of main
memory and few hundreds of Gigabytes of hard disk capacity are common. RAID (Redundant Array of inexpensive
disks) technology enables configuration of a bunch of disks as a single
large disk. It, thus, supports larger hard disk
space with better in-built reliability. During fifth generation, optical disks (popularly known as Compact Disks or
CDs) emerged as a popular portable mass storage media.
In the area of large
scale systems, fifth generation saw the emergence of more powerful super
computers based on parallel processing technology.
They used multiple processors and were of two types shared
memory and distributed memory
parallel computers.
In a shared memory
parallel computer, a high speed bus or communication network interconnects a
number of processors to a common main memory whereas in a distributed memory
parallel computer, a communication network interconnects a number of
processors, each with its own memory. These systems use parallel programming
technique to break a problem into smaller problem and execute them in parallel
on multiple processors of the system. Processors of a shared memory parallel
computer use memory access mechanism for communication,
where those of a distributed memory parallel computer message passing mechanism
for communication. Distributed memory parallel computers have better scalability (can grow larger in capability)
then shared memory parallel computers and are now built by clustering together
power full commodity workstations by using a high
speed commodity switch network. This is known as clustering technology.
During fifth generation, the internet emerged with associated
technologies and applications. It made possible for computer users sitting
across the globe to communicate with each other within minutes by use of
electronic mail (known as email) facility. A vast ocean of information became
readily available to computer user through the World
Wide Web (known as WWW). Moreover, several new types of existing
applications like electronic commerce, virtual
libraries, virtual classrooms, distance education, etc emerged during
the period.
The tremendous processing power and the massive storage
capacity of fifth generation computers also made them a very useful and popular
tool for a wide range of multimedia applications dealing with information containing text, graphics, animation, audio and video data. In
general, data size for multimedia information is much larger than plain
text information because representation of graphics, animation, audio, or video
media in digital form requires much larger number of bits than that required
for representation of plain text.
In the area of operating systems, some new concepts that
gained popularity during fifth generation include Microkernels,
Multithreading, and Multicore
operating system.
Microkernel technology enabled designers to model and
design operating system in a modular fashion. This makes operating systems easier to design and
implement, easier to modify or add new services, and allow users to implement
and use their own service.
Multithreading
technology is a popular way to improve application for performance through
parallelism.
A multicore operation 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 fifth generation
are JAVA programming language, and parallel programming libraries like MPI (Message Passing
Interface) and PVM (Parallel Virtual Machine).
JAVA is used primarily of the World Wide Web.
MPI is used for distributed
memory parallel computers and PVM is used for shared memory parallel computers.
CHARACTERISTICS:
1) Portable PCs called
notebook computers are much smaller, more powerful and handy
than PCs of fourth generation allowing users to use computer facility even
while travelling.
2) They consume less power
than their predecessors do.
3) No air conditioning is
required for notebook computers, desktop PCs, and workstations.
4) They are more reliable
and less prone to hardware failures,
requiring negligible maintenance cost.
5) They have faster and larger primary and secondary storage.
6) They are general purpose
machines.
7) Fifth generation computers work with natural language.
EXAMPLES:
IBM Notebooks, Pentium PCs, SUN
Workstations, IBM SP/2, SGI Origin 2000, PARAM Supercomputers are the
examples of fifth generation computers.
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