i.
Computer history and its
generation
The history of computer development is often referred to
in reference to the different generations of computing devices. Each of the
five generations of computers is characterized by a major technological
development that fundamentally changed the way computers operate.
The history of computer development is often referred to
in reference to the different generations of computing devices. Each of the
five generations of computers is characterized by a major technological
development that fundamentally changed the way computers operate, resulting in
increasingly smaller, cheaper, more powerful and more efficient and reliable
computing devices.
In this Webopedia reference article you'll learn about
each of the five generations of computers and the technology developments that
have led to the current devices that we use today. Our journey starts in 1940
with vacuum tube circuitry and goes to the present day -- and beyond -- with artificial intelligence.
First Generation
(1940-1956) Vacuum Tubes
The first computers used vacuum tubes for circuitry and
magnetic drums for memory, and were often enormous, taking up entire rooms.
They 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
malfunctions.
First generation computers relied on machine language,
the lowest-level programming language understood by computers, to perform
operations, and they could only solve one problem at a time. Input was based on
punched cards and paper tape, and output was displayed on printouts.
The UNIVAC and ENIAC computers are examples of
first-generation computing devices. The UNIVAC was the first commercial
computer delivered to a business client, the U.S. Census Bureau in 1951.
Second
Generation (1956-1963) Transistors
Transistors replaced vacuum tubes and ushered in the
second generation of computers. The transistor was invented in 1947 but did not
see widespread use in computers until the late 1950s. The transistor was far
superior to the vacuum tube, allowing computers to become smaller, faster,
cheaper, more energy-efficient and more reliable than their first-generation
predecessors. Though the transistor still generated a great deal of heat that
subjected the computer to damage, it was a vast improvement over the vacuum
tube. Second-generation computers still relied on punched cards for input and
printouts for output.
Second-generation computers moved from cryptic binary
machine language to symbolic, or assembly, languages, which allowed programmers
to specify instructions in words. High-level programming languages were also
being developed at this time, such as early versions of COBOL and FORTRAN.
These were also the first computers that stored their instructions in their
memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed for
the atomic energy industry.
Third Generation
(1964-1971) Integrated Circuits
The development of the integrated circuit was the
hallmark of the third generation of computers. Transistors were miniaturized
and placed on silicon chips, called semiconductors, which drastically increased
the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted
with third generation computers through keyboards and monitors and 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.
Computers for the first time became accessible to a mass audience because they
were smaller and cheaper than their predecessors.
Fourth
Generation (1971-Present) Microprocessors
The microprocessor brought the fourth generation of
computers, 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 Intel 4004 chip, developed in 1971, located all the
components of the computer—from the central processing unit and memory to
input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home
user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved
out of the realm of desktop computers and into many areas of life as more and
more everyday products began to use microprocessors.
As these small computers became more powerful, they could
be linked together to form networks, which eventually led to the development of
the Internet. Fourth generation computers also saw the development of GUIs, the
mouse and handheld devices.
Fifth Generation
(Present and Beyond) Artificial Intelligence
Fifth generation computing devices, based on artificial
intelligence, are still in development, though there are some applications,
such as voice recognition, that are being used today. 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.
ii.
Computer components
A computer system
consists of mainly four basic units; namely input unit, storage unit, central
processing unit and output unit. Central Processing unit further includes
Arithmetic logic unit and control unit, as shown in the figure:. A computer
performs five major operations or functions irrespective of its size and make.
These are
• it accepts
data or instructions as input,
• it
stores data and instruction
• it
processes data as per the instructions,
• it
controls all operations inside a computer, and
• it gives
results in the form of output.
RAM
a. Primary Memory can be further classified as RAM and
ROM.
• RAM or
Random Access Memory is the unit in a computer system. It is the place in a
computer where the operating system, application programs and the data in
current use are kept temporarily so that they can be accessed by the computer’s
processor. It is said to be ‘volatile’ since its contents are accessible only
as long as the computer is on. The contents of RAM are no more available once
the computer is turned off.
ROM or Read Only Memory is a special type of memory which
can only be read and contents of which are not lost even when the computer is
switched off. It typically contains manufacturer’s instructions. Among other
things, ROM also stores an initial program called the ‘bootstrap loader’ whose
function is to start the operation of computer system once the power is turned
on.
b. Secondary Memory
RAM is volatile memory having a limited storage capacity.
Secondary/auxiliary memory is storage other than the RAM. These include devices
that are peripheral and are connected and controlled by the computer to enable
permanent storage of programs and data.
CD ROM
Secondary storage devices are of two types; magnetic and
optical. Magnetic devices include hard disks and optical storage devices are
CDs, DVDs, Pen drive, Zip drive etc.
• Hard Disk
Hard disks are made up of rigid material and are usually
a stack of metal disks sealed in a box. The hard disk and the hard disk drive
exist together as a unit and is a permanent part of the computer where data and
programs are saved. These disks have storage capacities ranging from 1GB to 80
GB and more. Hard disks are rewritable.
• Compact Disk
Compact Disk (CD) is portable disk having data storage
capacity between 650-700 MB. It can hold large amount of information such as
music, full-motion videos, and text etc. CDs can be either read only or read
write type.
iii.
Advantages of using computer
This is a loaded question with many potentially right
answers. The potential advantages for using a computer depend closely on the
intended use. Given a few potential uses, here are some of my thoughts:
For writing:
Quick entry
Easy to edit and restructure
Many tools to produce various kinds of output (html,
text, books, pdf documents, etc.)
Storage is inexpensive and doesn't take up much space
Easy to search/navigate through documents
For organization
Many different kinds of tools from Palm software to
Franklin Covey, to GTD based on David Allen's system, to flat text files ala
todo.txt (http://www.todotxt.com) by Gina Trapani.
Once a document is in electronic form it is easy to store
and many, many documents can be stored on one computer in much less space than
in a file cabinet.
Easy to search
For programming
Most programming requires the use of computers
There are many, many tools available to programmers such
as:
Editors: CodeWrite, SlickEdit, VIM, EMACS, Notepad,
BBEdit...
Compilers: MSVC, Sun javac, GNU Compiler Collection
(java, fortran, C, C++, and more), Intel C Compiler...
Assemblers: NASM, MASM, TASM...
Interpreters: Ruby, Python, Lisp, Perl, bash, and countless
others
GUI Builders: Glade, QT Designer, MSVC, ...
Code browsers (many use output from etags or ctags, MS
has their own)
Simulators, Emulators
Using a computer makes it easy to search code and tools
make it easier to understand it
Easily gather programs from other creators
Easily distribute your own works
For research
Access to the Internet has become invaluable as a
research tool
Easily gather huge amounts of information and
store/catalog it
Easily search for new information or search the information
already acquired
Interact with other researchers to create/gather more
research
Almost instant access to many remote or obscure locations
of the globe and their researchers/experiences/knowledge
Easily disseminate results of your own research
