The computer has evolved from a large—sized simple calculating machine to a smaller but much more powerful machine. The evolution of computer to the current state is defined in terms of the generations of computer. Each generation of computer is designed based on a new technological development, resulting in better, cheaper and smaller computers that are more powerful, faster and efficient than their predecessors. Currently, there are five generations of computer. In the following subsections, we will discuss the generations of computer in terms of—
1.
The technology used by them (hardware and software),
2.
Computing characteristics (speed, i.e., number of instructions executed per
second),
3.
Physical appearance, and
4. Their applications.
First
Generation (1940 to 1956): Using Vacuum Tubes
Hardware Technology: The first
generation of computers used vacuum tubes (Figure) for circuitry and magnetic
drums for memory. The input to the computer was through punched cards and paper
tapes. The output was displayed as printouts.
Figure:
Vacuum tube
Software Technology: The instructions
were written in machine language. Machine language uses 0s and 1s for coding of
the instructions. The first generation computers could solve one problem at a
time.
Computing Characteristics: The
computation time was in milliseconds.
Physical Appearance: These computers
were enormous in size and required a large room for installation.
Application: They were used for
scientific applications as they were the fastest computing device of their
time.
Examples: UNIVersal Automatic Computer
(UNIVAC), Electronic Numerical Integrator And Calculator (ENIAC), and
Electronic Discrete Variable Automatic Computer (EDVAC).
The
first generation computers used a large number of vacuum tubes and thus
generated a lot of heat. They consumed a great deal of electricity and were
expensive to operate. The machines were prone to frequent malfunctioning and
required constant maintenance. Since first generation computers used machine
language, they were difficult to program.
Further Details: Bulky, vacuum based and
costly, used assembly language which was translated to machine level language
for execution. These computers were used mainly for scientific calculations. Examples:
ENIAC, EDSAC, EDVAC, UNIVAC.
Second
Generation (1956 to 1963): Using Transistors
Hardware Technology: Transistors
(Figure) replaced the vacuum tubes of the first generation of computers.
Transistors allowed computers to become smaller, faster, cheaper, energy
efficient and reliable. The second generation computers used magnetic core technology
for primary memory. They used magnetic tapes and magnetic disks for secondary
storage. The input was still through punched cards and the output using
printouts. They used the concept of a stored program, where instructions were
stored in the memory of computer.
Figure:
Transistors
Software Technology: The instructions
were written using the assembly language. Assembly language uses mnemonics like
ADD for addition and SUB for subtraction for coding of the instructions. It is
easier to write instructions in assembly language, as compared to writing instructions
in machine language. High-level programming languages, such as early versions
of COBOL and FORTRAN were also developed during this period.
Computing Characteristics: The
computation time was in microseconds.
Physical Appearance: Transistors are
smaller in size compared to vacuum tubes, thus, the size of the computer was
also reduced.
Application: The cost of commercial
production of these computers was very high, though less than the first
generation computers. The transistors had to be assembled manually in second
generation computers.
Examples: PDP-8, IBM 1401 and CDC 1604.
Second
generation computers generated a lot of heat but much less than the first
generation computers. They required less maintenance than the first generation
computers.
Further Details: Smaller than vacuum based
computers, but better performance-wise, used transistors instead of vacuum
tubes. High level languages such as FORTRAN and COBOL were used. Punched cards
continued to be used during this period. Computers, then, were used
increasingly in business, industry and commercial organizations. Examples: IBM
7030, Honeywell 400.
Third
Generation (1964 to 1971): Using Integrated Circuits
Hardware Technology: The third
generation computers used the Integrated Circuit (IC) chips. Figure 1.6 shows
IC chips. In an IC chip, multiple transistors are placed on a silicon chip.
Silicon is a type of semiconductor. The use of IC chip increased the speed and
the efficiency of computer, manifold. The keyboard and monitor were used to
interact with the third generation computer, instead of the punched card and
printouts.
Figure:
IC chips
Software Technology: The keyboard and
the monitor were interfaced through the operating system. Operating system
allowed different applications to run at the same time. High-level languages
were used extensively for programming, instead of machine language and assembly
language.
Computing Characteristics: The
computation time was in nanoseconds.
Physical Appearance: The size of these
computers was quite small compared to the second generation computers.
Application: Computers became accessible to mass audience.
Computers were produced commercially,
and were smaller and cheaper than their predecessors.
Examples: IBM 370, PDP 11.
The
third generation computers used less power and generated less heat than the
second generation computers. The cost of the computer reduced significantly, as
individual components of the computer were not required to be assembled
manually. The maintenance cost of the computers was also less compared to their
predecessors.
Further Details: Small Scale
Integration and Medium Scale Integration technology were implemented in CPU,
I/O processors etc. Faster processors with magnetic core memories that were
later replaced by RAM and ROM. This is when microprogramming was introduced as
were operating system software. Database management, multi-user application,
online systems like closed loop process control, airline reservation,
interactive query systems, automatic industrial control, etc. emerged during
this period. Examples: System 360 Mainframe from IBM, PDP-8 Mini Computer from
Digital Equipment Corporation.
Fourth
Generation (1971 to present): Using Microprocessors
Hardware Technology: They use the Large
Scale Integration (LSI) and the Very Large Scale Integration (VLSI) technology.
Thousands of transistors are integrated on a small silicon chip using LSI
technology. VLSI allows hundreds of thousands of components to be integrated in
a small chip. This era is marked by the development of microprocessor.
Microprocessor
is a chip containing millions of transistors and components, and, designed
using LSI and VLSI technology. A microprocessor chip is shown in Figure .
This
generation of computers gave rise to Personal Computer (PC). Semiconductor
memory replaced the earlier magnetic core memory, resulting in fast random
access to memory. Secondary storage device like magnetic disks became smaller
in physical size and larger in capacity. The linking of computers is another
key development of this era.
The
computers were linked to form networks that led to the emergence of the
Internet. This generation also saw the development of pointing devices like
mouse, and handheld devices.
Figure: Microprocessors
Software Technology: Several new
operating systems like the MS-DOS and MS Windows developed during this time.
This generation of computers supported Graphical User Interface (GUI). GUI is a
user-friendly interface that allows user to interact with the computer via
menus and icons. High-level programming languages are used for the writing of
programs.
Computing Characteristics: The
computation time is in picoseconds.
Physical Appearance: They are smaller
than the computers of the previous generation. Some can even fit into the palm
of the hand.
Application: They became widely
available for commercial purposes. Personal computers became available to the
home user.
Examples: The Intel 4004 chip was the
first microprocessor. The components of the computer like Central Processing
Unit (CPU) and memory were located on a single chip.
In
1981, IBM introduced the first computer for home use. In 1984, Apple introduced
the Macintosh.
The
microprocessor has resulted in the fourth generation computers being smaller
and cheaper than their predecessors. The fourth generation computers are also
portable and more reliable.
They
generate much lesser heat and require less maintenance compared to their predecessors.
GUI
and pointing devices facilitate easy use and learning on the computer.
Networking has resulted in resource sharing and communication among different
computers.
Further Details: Microprocessors were
introduced where complete processors and large section of main memory could be
implemented in a single chip. CRT screen, laser & ink jet printers,
scanners etc. were developed and so were LAN and WANS. C and UNIX were used.
Examples: Intel’s 8088,80286,80386,80486 .., Motorola’s 68000, 68030, 68040,
Apple II, CRAY I/2/X/MP etc.
Fifth
Generation (Present and Next): Using Artificial Intelligence
The
goal of fifth generation computing is to develop computers that are capable of
learning and self-organization. The fifth generation computers use Super Large
Scale Integrated (SLSI) chips that are able to store millions of components on
a single chip. These computers have large memory requirements.
This
generation of computers uses parallel processing that allows several
instructions to be executed in parallel, instead of serial execution. Parallel
processing results in faster processing speed. The Intel dual core
microprocessor uses parallel processing.
The
fifth generation computers are based on Artificial Intelligence (AI). They try
to simulate the human way of thinking and reasoning. Artificial Intelligence
includes areas like Expert System (ES), Natural Language Processing (NLP),
speech recognition, voice recognition, robotics, etc.
Further Details: Computers use
extensive parallel processing, multiple pipelines, multiple processors etc.
Portable notebook computers introduced. They also started using object oriented
languages such as JAVA. Quantum mechanism and nanotechnology available here
will radically change computers for all times.
Examples:
IBM notebooks, Pentium PCs-Pentium 1/2/3/4/Dual core/Quad core. SUN work
stations, Origin 2000, PARAM 10000, IBM SP/2.
Table:
Generation of Computer hardware
Figures Table: All 5 generation computers images for comparison
1st Generation Computer Image
2nd
Generation Computer Image
3rd
Generation Computer Image
4th Generation Computer Image
5th
Generation Computer Image
Post activity:
In
this post we covered profiles of computer- generations in detail. If more
detailed information is needed please browse or search the internet for above
terms. All images are from Google search.
Keywords:
Computer, Generations of computer.
…till next post, bye-bye and take
care.
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