Computer Fundamentals Introduction, History, Generation, Classification, Input Devices
Computer Fundamentals
Introduction
The term computer is derived from the word compute. A Computer is an electronic device
that takes data and instructions as an input from the user, processes data, and provides useful
information known as output. PDF Download Link https://drive.google.com/open?id=1u9TaasG_xzBT30GlMo0yvwGg2GiStwdf
This cycle of operation of a computer is known
as the input-process-output cycle in fig 1.1. The electronic device is
known as hardware and the set of instructions is known as software.
 |
| Input-Process-Output |
They have
strengthened man’s powers in numerical computations and information processing.
Modern computers possess certain characteristics and abilities peculiar to
them. They can :
I.
Perform
complex and repetitive calculations rapidly and accurately.
II.
Store large amounts of data and information for subsequent manipulations.
III.
Hold
a program of a model which can be explored in many different ways.
IV.
Compare
items and make decisions.
History of Computers
The use of computing techniques is over 5000
years old. The Babylonians, Chinese, and Egyptians had used numerical methods
for the survey of lands and the collection of taxes as early as 3000 BC.
Computing history starts with the development of a device called the abacus by the Chinese around this period.
This was used for the systematic calculation of arithmetic operations. The
first accounting machine known as Pascaline was built by Blaise Pascal (a French
Mathematician and thinker) in 1642. Then came the Leibnitz
Calculator developed by
Gottfried Wilhelm Leibnitz, a German philosopher and mathematician in 1671..
 |
| Abacus |
During the beginning of the 19th century, Joseph Marie Jacquard a French textile manufacture invented an automated loom operated by a mechanism controlled by punched cards. The Origin of the modern computer can be traced back to 1834, when an English mathematician Charles Babbage designed an analytical engine. This was considered the first programmable digital mechanical computer.
Generations of Computers
·
First
generation (1940-1956)
·
Second
generation (1946-1963)
·
Third
generation (1964-1971)
·
Fourth
generation (1971-till date)
·
Fifth
generation (1980-Present)
First-Generation Computers
In this
generation of Computers, vacuum tubes were used to build the circuitry for the computers and magnetic drum
was used for the memory of the computer. A vacuum tube was a device made up of
glass and used filaments to generate electrons. It was used to amplify the
electronic signals.
 |
| Vacuum Tubes |
The first-generation computers used to
perform calculation in milliseconds. They were the fastest known computers of
their time. The size of these computers was very large, and a single computer
was used to cover the space of an entire room. Since the size of the computers
was very large, they used to consume a great deal of electricity and generated
a large amount of heat.
These computers were used to take inputs
from punch cards and paper tapes and displayed the results on paper as
printouts. The Computers that fall under the first generation of computers are ENIAC, EDVAC and UNIVAC. These computers were used for
scientific calculations.
Second-Generation Computers
In the
second generation of computers, transistors were used instead of vacuum tubes.
Transistors were invented in 1947 by John Bardeen, William Shockley, and Walter
Brattain. The transistors were faster and more reliable than vacuum tubes. In
addition, the size of the transistors was smaller than vacuum tubes and they
generated less heat as compared to vacuum tubes.
 |
| Transistors |
The second generation computers used assembly
language instead of machine
language. The use of
assembly language helped the programmer to specify instructions in the form of
words. The task of the programmer thus become easier with the development of
high-level language like COBOL and FORTRAN. These computers use magnetic tapes and magnetic disks as external
storage devices. IBM 1620, PDP8 and CDC1604 are example of second generation computers.
Third-Generation Computers
The third
generation of computers were characterized by the development of the Integrated
Circuit (IC), which was
developed by Jack Kilby, in 1958. An IC is a silicon chip that embeds an electronic circuit,
which comprises several components, such as transistors, diodes and resistors. The use of ICs had increased the
speed and efficiency of the computers to a significant extent.
These computers used a keyboard, which is
an input device, for accepting data from users and displayed the output on the
monitor, which is an output device. Examples of third generation computers
include IBM 370, PDP11 and CDC 7600.
Fourth-Generation Computers
The fourth
generation of computers is characterized by the use of Large Scale
Integration (LSI)
circuits and Very Large Scale Integration (VLSI) circuits in the construction of
computing components. In fourth generation computers, LSI and VLSI circuits
were further integrated on a single silicon chip, termed as microprocessor, containing control logic and
memory. The fourth generation of computers had also seen the inceptions of
several new operating systems including MS DOS and MS Windows. Example of
fourth generation computers is the Personal Computer (PC).
A special characteristic of the
fourth generation computers is the Graphical User Interface (GUI), which is user-friendly
interface that provides icons and menus. Various other characteristics of the
fourth generation computers are :
·
These
computers were smaller and cheaper than the computers of the previous
generation.
·
They
were more reliable than the third generation computers.
·
The
fourth-generation of computers used high-level programming languages.
Fifth-Generation Computers
The fifth
generation computers is characterized by the Ultra Large
Scale Integration
(ULSI) technology, which is more powerful as well as faster than the
microprocessors used by the computers of the fourth generation.
 |
| Intel Microprocessor Chip |
This
generation of computers has also seen the introduction of optical disks, which
have soon emerged as a popular portable mass storage medium. These optical
disks are popularly known as Compact Disk-Read Only Memory (CD-ROM), as they
are primarily used for storing data, which is only readable.
Classifications of Computers
Computers can be classified into several categories :
- · Microcomputer
- · Minicomputer
- · Mainframe Computers
- · Supercomputers
Microcomputers
A
microcomputer is defined as a computer that has a microprocessor as its CPU.
The microcomputer system can perform the following basic operations :
- ·
Inputting --- It is the process of Entering data and
instructions into the microcomputer system.
- ·
Storing --- It is the process of saving data and
instructions in the memory of the microcomputer system, so that they can be use
whenever required.
- ·
Processing --- It is the process of performing arithmetic or
logical operations on data, where data can be converted into useful
information.
- ·
Outputting --- It provides the results to the user, which
could be in the form of visual display and/or printed reports.
- ·
Controlling --- It helps in directing the sequence and manner
in which all the above operations are performed.
Minicomputers
A minicomputer is a medium-sized computer that
is more powerful than a microcomputer. An important distinction b/w a
microcomputer and a minicomputer is that
a minicomputer is usually designed to serve multiple users simultaneously. They
are more expensive than microcomputers.
Mainframe Computers
Mainframe computers are those computers, which
help in handling the information processing of various organizations like
banks, insurance companies, etc. Mainframe computers are placed on a central
location and are connected to several user terminals. Mainframe computers are
larger and expensive in comparison to workstations.
Supercomputers
Supercomputers are the most Powerful and
expensive computers available at present. They are also the fastest computers
available. Supercomputers are primarily used for complex scientific
applications, which need a higher level of processing. Presently, some of the
popular manufactures of supercomputers are IBM, silicon Graphics, Fujitsu and
Intel.
BASIC ANATOMY OF COMPUTER SYSTEM
A computer system comprises of hardware and software components. Hardware refers to the physical parts of the
computer system and Software is the set of instructions or programs that are
necessary for the functioning of a computer to perform certain tasks. Hardware
includes the following components :
·
Input Devices --- They are used for accepting data on which the
operations are to be performed. Examples are keyboard, mouse, etc.
·
Processor --- Also known as CPU, it is used to perform the
calculations and informations processing on the data that is entered through
the input device.
·
Output Devices --- They are used for providing the output of a
program that is obtained after performing the operations specified in a
program. Examples are Monitor, etc.
·
Memory --- It is used for storing the input data as well
as the output of a program that is obtained after performing the operations
specified in a program. Examples are RAM (Random Access Memory), HD (Hard
Disk), etc.
Software supports the functioning of a computer
system internally and cannot be seen. It is stored on secondary memory and can
be an application software as well
as system software. The application
software is used to perform a specific task according to requirements and the
system software is mandatory for running application software. Examples of
application software include Excel and MS Word and Examples of system software
include Operating System and Networking system.
INPUT DEVICES
Input Devices can be connected to the computer
system using cables. The most commonly used input device among others are :
·
Keyboard
·
Mouse
·
Scanner
Keyboard
A standard keyboard includes alphanumeric keys,
function keys, modifier keys, numeric keys, cursor movement keys, spacebar key,
escape key, and some special keys, such as Page Up, Page Down, Home, Insert,
Delete and End.
Mouse
The mouse allows the user to select elements on
the screen, such as tools, icons, and buttons, by pointing and clicking them.
We can also use a mouse to draw and paint on the screen of the computer system.
The mouse is also known as pointing device.
The
mouse consists of two buttons, a wheel at the top and a ball at the bottom of
the mouse. When the ball moves, the cursor on the screen moves in the direction
in which the ball rotates. The left button of the mouse is used to select an
element and the right button, when clicked, displays the special options.
Scanner
A scanner is an input device that converts
documents and images as the digitized images understandable by the computer
system. The digitized images can be produced as black and white images, gray
images, or colored images.
 |
| Scanner |
In case
of colored images, an image is considered as a collection of dots with each dot
representing a combination of red, green, and blue colors, varying in
proportions. The proportions of red, green. And blue colors assigned to a dot
are together called as color description.
There are following types of scanners that can
be used to produce digitized images :
·
Flatbed Scanner --- It contains a scanner head that moves across a
page from top to bottom to read the page and converts the image or text
available on the page in digital form. The flatbed scanner is used to scan
graphics, oversized documents, etc.
·
Drum Scanner --- In this type of scanner, a fixed scanner head
is used and the image to be scanned is moved across the head. The drum scanner
are used for scanning prepress materials.
·
Slide Scanner --- It is a scanner that can scan photographic
slides directly to produce files understandable by the computer.
·
Handheld Scanner --- It is a scanner that is moved by the end user
across the page to be scanned. This type of scanner is inexpensive and small in
size.
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