HISTORY OF COMPUTER

1
Prepared by AmjadKhanAfridi
INFORMATION TECHNOLOGY (IT):- Information Technology is a
technology that merges computers with high-speed communication links
carrying data. Or Information Technology = MIS (Management Information
sciences) + EDP (Electronic data Processing).
COMPUTER: - A computer is a machine, which accepts data from input
devices performs arithmetical and logical operations in accordance with
predefined programs and finally transfers the processed data to output
devices.
HISTORY OF COMPUTER
1. ABACUS: It was the first manual calculating device. It was
developed about 5000 B.C years ago in Babylonia. It is also known as
“SOROBAN”. It is interesting to note that it is still used in now days as a toy.
2. NAPIER’S BONE: Another manual calculating device was Napier’s
bone. It was developed by John Napier in 1600 A.D. John was
mathematician. He also introduced logarithms. Napier’s bone construct from
strips of bones.
3. PASCALINE: It was the first mechanical adding machine. It was
invented by 19 years old Blaise Pascal in 1642 A.D. he was a French
mathematician. The father of Pascal was tax collector.
4. LEIBNITZ’S MACHINE: In 1694 A.D Baron Gottfried Wilhelm
Von Leibnitz of Germany invented the first calculator for multiplication and
division. It also finds the square root.
5. JACQUARD’S LOOM: Joseph jacquard introduced the punched
card in 1801A.D. Joseph was a French textile manufacturer developed a
system which used punched card for controlling the weaving loom.

6. DIFFERENCE ENGINE & ANALYTICAL ENGINE: Charles
Babbage, Nineteen century professor at Cambridge University is considered
to be the father of modern digital computers. Like Pascal and Leibnitz, this
Englishman also was a mathematician and wants to build a machine that
could perform calculation, so he developed “Difference Engine” in 1822. In
1823 he started to improve Difference Engine. Actually he wants to develop a
complete calculating machine (Analytical Engine) but he failed because the
standard of engineering was not outstanding, therefore machine was never
completed. But infact the succeeded establishing the basic principals on
which Modern Computer are constructed.
7. MARK 1: It was the first electro mechanical device and was the first
fully automatic calculating machine designed by Howard A. Aiken of
Harvard University in Collaboration with IBM (International Business
Machines) Corporation. Its design was based on the techniques already
developed for punched card machine. This project was started in 1937 and
completed in 1944. Mark 1 was approximately 55 feet long and 8 feet high.
GENERATIONS OF COMPUTER
There are total five Generations of Computer.
1. FIRST GENERATION OF COMPUTER (1942-1955): In first
Generation Computers Vacuum tubes are used. In 1946 Professor J.Presper
Eckert and John Mauchly developed a first vacuum tube computer named
ENIAC (Electronic Numeric Integrator and Calculator) at Moore school of
Engineering of the University of Pennsylvania. It took up the wall space in a
20x40 square feet room and used 18000 vacuum tubes. ENIAC has no idea of
stored program concept. In 1946 Dr. John Von Neumann started work the
EDVAC (Electronic Discrete Variable Automatic Computer), which was the
concept of stored program. But before EDVAC the Englishman Maurice

developed EDSAC (Electronic Delay Storage Automatic Calculator) in 1949.
Actually the EDVAC was completed in 1952. Therefore EDSAC was the
first stored program computer, which was developed by Maurice. In 1951 J.P
Eckert and John developed UNIVAC (Universal Variable Automatic
Computer) which was the first digital computer, which was not “One of a
kind”. UNIVAC also used in the Census Bureau in 1951 and was used
continuously for 10 years. The first Business Oriented computer UNIVAC -1
was developed by General Electronic Corporation in 1954. Punch cards are
used for feeding and getting information.
2. SECOND GENERATIONS (1955-1965): The transistors, invented
by Bell Telephone Laboratories in 1948, formed the basis for second
generation of computers. Trough use of the transistor, these computers was
much faster, more reliable and more versatile than first generation computers.
Like first generation Punched cards and magnetic tape used for input of data.
Developed the high level languages like FORTRAN, COBOL, and BASIC
etc. The typical computers are IBM 650, BURROUGHS 220.
3. THIRD GENERATIONS (1965-1975): Advances in electronic
technology continued and the advent of technology made it very small
surface of silicon known as “Chips”. This new technology was called ICs
(Integrated Circuits). The 3rd generation was based on ICs technology.
Through the use of IC’s these computers were even more reliable, smaller
than second generation computers. Even easily portable and even lower heat
generated than 2nd generation computers. Monitors and Keyboards, were
introduced for data input and output.
4. FORTH GENERATION (1975-PRESENT): Initially the
integrated circuits contained only about ten components. This technology
named Small Scale Integration (SSI), later it because possible to integrate
unto a hundred components on a single chip. This technology came to be

known as Medium Scale Integration (MSI). Than came the era of Large Scale
Integration (LSI) when it was possible to integrated over 30,000 components
onto a single chip. Effort is still on for further miniaturization and it is
expected that more than one million components will be integrated on a
single chip known as Very Large Scale Integration (VLSI).
5. FIFTH GENERATION: Scientists want that computer produce
which has Human like qualities, such as learning, reasoning, communicating,
seeing and hearing. This new technology is named AI (Artificial
Intelligence). Today the main areas of AI are robotics, perception systems,
genetic algorithm and natural language processing etc.
TYPES OF COMPUTER
Computer can be classified into two main categories.
1. CLASSIFICATION ACCORDING TO LOGIC USED.
2. CLASSIFICATION ACCORDING TO SIZE USED.
Logically computer can be classified into three types.
1. Analog Computers.
2. Digital Computers.
3. Hybrid Computers.
1. Analog computers recognize data as a continuous measurement of a
physical property or which is not discrete or separate. Analog data includes
temperature, pressure, current and voltage. The analog computers are
automobile speedometer, analog watch etc.
2. Digital computers process information which is based on the
presence or absence of an electronic charge or we prefer to say a binary 1 or
0. A digital computer further grouped into two categories.

1. Special purpose computer: - These are those digital
computers which are made and used for specific job. Special purpose
computers are most efficient because they are designed to do a single job.
The example of special purpose computers are Calculator, watch etc.
2. General purpose computer: - These are versatile and are
used in many areas such as Business, manufacturing, educations and science
etc. We can use general purpose computers for business applications as well
as for scientific purposes and for processing complex mathematics etc.
3. Hybrid computers are the best combination of both digital and
analog Computers. It consist the best features of both computers.
Classification according to size computers are of four types.
4. Super Computers.
5. Mainframe Computers.
6. Mini Computers.
7. Micro Computers.
1. A Super computer is generally characterized as being the
fastest, most powerful and most expensive computer and having surprising
features. They calculate at rates up to 1.2 billion instructions per second.
They are widely used in scientific applications such as aerodynamic designed
and also used in weapons technology, weather forecasting and satellite etc.
They can take input from over 10000 individual workstation. One of the most
powerful supercomputer today, the Cray-1 and Cray-2 is set up in C shape.
2. A Mainframe computer is usually slower, less powerful and
less expensive than Super computer. Mainframes process data at several
million instructions per second. More than 1000 remote workstations can be
attached with this computer. Mainframes are used by Banks, large business
industries etc.

3. Mini computer is slim down version. Mini-computer was first
use in 1960. Most of the earliest minis were used for engineering and
scientific applications. Later, minis were used in small business. Mini has the
ability to drive a number of terminals, printers and other devices.
4. A Micro computer is the smallest, least expensive of all the
computers Microcomputer that uses a microprocessor as its Central
Processing Unit (CPU) also called personnel computer system.
Microcomputer is first use in the 1970s. Microcomputer is use within
business for normal data processing. It is also called home computer.
CAD AND CAM
Computer aided design (CAD):- Product designers or engineers use technology
to design a product, and before if goes into production to test it for such concerns
as safety, durability etc. The initial design can be input to the CAD, and then it
can be tested. As changes are suggested, the original design is edited. As
techniques are applied to CAD to analyze the design and test product performance
under various conditions. CAD is use in designing such products as
automobiles, aircraft, ships, buildings, electric circuits, advertising and more
productions.
Computer aided Manufacturing (CAM):- CAM is an umbrella term that
includes any use of computers in manufacturing operations CAM can be use in
the follow fields such as monitoring, in monitoring the use of computer to open
and shut values at an oil refinery, when a certain temperature is reached in an oil
tank. In the numeric control field to controlling manufacturing processes by
computer, a special type of numeric control is robotics.

NETWORKING AND ITS TYPES AND ADVANTAGES
TYPES OF NETWORKING
A communication between two or more than computers which share some
resources (Computer Parts and Programs) is called Network. --------- OR ---------
A communication network or a network is system of interconnected computers,
telephones or other communications devices that can communicate with one
another and shares applications and data. Networks are classified principally in
the following three sizes.
LAN: - LAN stands for Local Area Network. A LAN is a privately Owned
communication network that serves users within a confined geographical area.
The range is usually with a mile perhaps one office, one building or a group of
buildings close together, as a college campus. LANs are designed to allow
resources to be shared between personal computers or workstations. The
resources to be shared can hardware or software.
MAN: - MAN stands for metropolitan area network. A MAN is a Communication
network covering area the size of a city. The range is usually one mile to ten
miles. MAN may be a single network such as a cable television network, or it
may be a means of connecting a number of LANs into a larger network so that
resources may be shared LAN to LAN as well as device to device. A MAN may
be wholly owned and operated by a private company, or it may be a phone
companies.
WAN: - WAN stands for Wide area network. WAN is a Communication that
covers a wide area geographical area, such as a state or a country. Internet is the
example of WAN.
ADVANTAGES OF NETWORKS

Sharing of peripheral devices: - Laser printers, disk drives and scanners are the
examples of peripheral devices. With the help of networking we can also sharing
these devices.
Sharing of programs and data:- In most organizations, peoples use the same
software and need access to the same information. It could be expensive for a
company to buy a copy of program for each employee. Therefore with the help of
network we also share the same program and data.
Better communications:- One of the greatest features of networks is electronic
mail. With email everyone on a network can easily keep others posted about
important information.
Security of information:- Networks also allows the security of information.
Today’s data would be backed up or duplicated on a networked storage device
shared by others.
Access to databases:- Networks also enable users to logon into many databases,
whether the private databases of a company or public database available online
through the Internet.
TOPOLIGIES
The logical layout or shape of a local area network is called topology. The five
basic topologies are Bus, Ring, Star, Tree, Mesh and Hybrid.
BUS: In a bus network, all communication devices are connected to a common
channel. There is no central server. The advantage of a bus network is that it may
be organized as a Client/Server or peer-to-peer network. Bus or Highway network
is ease of Installation. Disadvantages include difficult reconfiguration and fault
isolation. If a connection in the bus is broken the entire network may stop
working. There is no security in Bus network.
RING: A ring network is one in which all Microcomputers and other
communications devices are connected in a continuous loop. Electronic messages
are passed around the ring. There is no central server. The messages flow in only

one direction. However, unidirectional traffic can be a disadvantage. If a
connection is broken the entire network stop working.
HYBRID: It’s the combinations of Star, Ring and Bus Networks. For example a
small college might use a bus network to connect building and star, ring networks
within certain building.
Star: A star network is one in which all PCs and other Communications devices
are connected to a central server. In star network the hub (device) is used on it.
The advantage of a star network is that the hub prevents collisions between
messages. If connection is broken between any communications device and the
hub, the rest of the devices on the network will continue operating.
Tree: A tree topology is a variation of a star; nodes in Tree are linked to a central
hub that controls the traffic to the network. However, not every device plugs
directly into the central hub. The majority of devices connect to a secondary hub
that in turn is connected to the central hub. The central hub in the tree is an active
hub. An active hub contains a repeater, which is a hardware device that
regenerates the received bit patterns before sending them out. The secondary hub
may be active or passive. A passive hub provides a simple physical connection
between the attached devices. The Advantages and disadvantages of a tree
topology are generally the same as those of a star but some of additional
advantages also. First it allows more devices to be attached to a single central hub
and can therefore increase the distance a signal can travel between devices.
Second it allows the network to isolate and prioritize communications from
different computers. A good example of tree can be seen in cable TV.
Mesh: In a mesh topology, every device has a dedicated point to point link to
every other device. The term dedicated means that the link carries traffic only
between the two devices it connects. A mesh Topology has n (n-1)/2 physical
channels to link n devices. A mesh offers several advantages. First the use of
dedicated links guarantees that each connection can carry its own data. Second a
mesh topology is robust. If one link becomes unusable, it does not incapacitate the

entire system. Another advantage is privacy or security. When every message sent
travels along a dedicated line. Finally point to point links make fault identification
and fault isolation. The main disadvantages of mesh are related to the amount of
cabling and the number of I/O ports required.
CABLE OF NETWORKING
TWISTED PAIR WIRE.
COAXIAL CABLE.
FIBER OPTIC CABLE.
Twisted Pair wire: It is type of communication channel. Twisted pair wire has
been the most common channel used for telephone systems. It is relatively slow
and does not protect well against electrical interference.
Coaxial cable: It is also the type of Communication channel. It is much better at
resisting noise than twisted a faster rate.
Fiber optic: It is type of communication channel consisting of hundreds or
thousands of thin strands of glass that transmit pulsating (energetic or animated)
beams of light. It is most speedy cable of communication.
NETWORK INTERFACE CARD (NIC): Circuit board inserted into an
expansion slot in a microcomputer that enables it to send and receive messages on
a local area network. Without a network interface card a microcomputer can not
be used to communicate on a LAN. NIC also called Ethernet card because a
network which developed by LAN is called Ethernet. Ethernet hardware can be
categorized into two general parts. The first type of coaxial hardware is used for
10Base2 and 10Base5 networks. The second type of hardware is twisted pair
(TP).
BNC T-CONNECTOR: Attaches to the network card and allows the computer
to be inserted between two pieces of coaxial cable.

BNC TERMINATOR: A Terminator provides a grounding wire. At least one
terminator on every network trunk segment should be grounded.
REPEATER: Repeater is a device which often used to connect long cable
segments between LAN.
RJ-45 CONNECTOR: It connects twisted pair cabled to a computer. After the
category of cable has been chosen RJ (Register Jack)-45 connectors are placed on
either end of the cable.
INFORMATION TECHNOLOGY AND ITS ELEMENTS
Information technology is technology that merges computing with high speed
communication links carrying data, sound and videos. There are six elements of
computer and communication system.
1. People or Personnel.
2. Procedures.
3. Data and Information.
4. Hardware.
5. Software.
6. Communication.
People: Those peoples which are involved in a computer organization or in a
computerized environment are called computer personnel. Important computer
personnel are the following.
1. System Analyst: He studies information needs and data processing
requirements, designed a data processing system, prepare program
specifications and implement his designed system.
2. Database Administrator: He creates and maintains database and plans
hardware and software according to his requirements.

3. Supervisor: He is responsible to supervise the performance of operators.
He also checks the reports created by the operators.
4. Operator: He is involved in data entering tasks.
Procedure: These are the policies that control the operation of the computer
system. Or the step by step instruction.
Data and information: A collection of raw facts that is entered as input,
processed and transformed into meaningful information is called data. Actually
the original word is datum (The singular form of data), which is Greek word and
meaning “something given”. Data that has been processed so that it is meaningful
and useful for mangers and operating staff is called Information.
Hardware: The Physical parts of computer are called Hardware e-g Monitor,
CPU, RAM or Keyboard etc.
Software: Software contains computer programs that are the complete set of
instructions, which are use, the computer to perform work. There are two types of
software.
1. Application Software: Contains user-oriented programs written in
programming languages, such as COBOL, Basic, FoxPro etc and software
packages which are made by software companies for specific purposes,
such as word processor, spreadsheet, database management etc.
2. System Software: Consists of “back ground” programs that enable
applications software to run on specific set of hardware. At the heart of
operating system is a program called supervisor, which control the
operation of operating system. Another part is command-language
translator that converts the user’s commands into machine language for
execution. The input/output control system interacts with input and output
devices, performs functions like take inputs from input devices, place the
result on display devices.

Communication: It is the 6th element of computer and communication.
Communication is the electronic transfer of data from one place to another.
ARTIFICIAL INTELLIGENCE
Artificial Intelligence is a group of related technologies that attempt to develop
machines to emulate human like qualities such as learning, reasoning,
communicating, seeing and hearing. Today the main areas of AI are:
3. Robotics.
4. Perception System.
5. Expert System.
6. Natural language processing.
7. Fuzzy logic.
Robotics: Robotics is a field that attempts to develop machine that can perform
work normally done by people. The machines themselves of course are called
Robots. A Robot is an automatic device that performs functions ordinary ascribed
to human beings or that operates with what appears to be almost human
intelligence.
Perception System: These are sensing devices that emulate the human
capabilities of sight, hearing, touching, smell. Clearly perception systems are
related to robotics, since robots need to have at least some sensing capabilities.
Expert System: - It is also the field of AI. An expert system is an interactive
computer program that helps users solves problems that would otherwise require
the assistance of human expert.
Fuzzy Logic: It is a method of dealing with imprecise data and uncertainly with
problems that have many answers rather than one.
Neural Networks: Neural network use physical electronic devices or software to
mimic neurological structure of human brains.

SOFTWARE
Software contains computer programs that are the complete set of instructions,
which are use, the computer to perform work. There are two types of software.
__________APPLICATION SOFTWARE__________
Application software contains user-oriented programs written in
programming languages, such as COBOL, Basic, FoxPro etc and software
packages which are made by software companies for specific purposes, such as
word processor, spreadsheet, database management etc. There are two main
categories of application software: COMPUTER LANGUAGES and COMPUTER
PACKAGES.
(A) COMPUTER LANGUAGES: Computer Languages is the software
which developed for computer Programmers to create any package for operator or
user for some facilities. And Programming is the process of devising programs in
order to achieve the desired goals using computers. In other words it is the
process of converting broad system specifications into usable machine
instructions that produce desired results. All computer programming languages fit
into four general categories, namely,
1. Low Level Languages
2. High-level Languages
3. Fourth Generation Languages
1. Low Level Languages: Low level languages consist of further two types
and they are Machine language and Assembly language. These languages are
difficult to understand as compare to High level languages. A computer’s machine
language consists of strings of binary numbers (i-e 0s and 1s) and is the only one
the processor directly understands. Machine language programs have an
advantage of very fast execution speeds and efficient use of primary memory.
Assembly language is also classified as low level languages because detailed

knowledge of hardware specifies is required. It uses symbolic addressing
capabilities. Normally these languages are used to develop different type of
Operating software or other high level languages.
2. High level Languages: These are languages whose instructions closely
resemble human language and mathematical notation. Unlike assembly language
made in this language may be used with different makes of computers with little
modification. Other advantages of high level languages are:
1. Easier to learn
2. Requires less time to write
3. Provides better documentation
4. Easier to maintain.
High level languages must also be translated into machine language
before they can be used by a computer. Names of a few high level languages
being used now days are:
BASIC (Beginner’s All-Purpose Symbolic Instruction Code), FORTRAN
(FORmula TRANslator), ALGOL (ALGOrithmic Language), COBOL
(COmmon Business Oriented Language), PASCAL and C etc.
3. Fourth Generation Languages: These are the languages which are
developed in fourth Generation of computer. Before these High level languages
are developed but these languages are known as procedural languages. 4GL is a
non-procedural language. Mostly they are Object Oriented languages which have
some additional features. The objectives of 4GL include:
1. Increase the speed of developing programs.
2. Minimize user’s efforts to obtain information from computer.
3. Decrease skill level required of users.
4. Reduce errors or make programs that are easy to change.
Some popular 4GL are Visual Basic, C++, Java, C# etc.

(B) PACKAGES: An Application Package is software that, in
conjunction with the system software, instructs the computer how to do the job.
Application Software helps the user work faster, more efficiency, and thus more
productively than if the job was done manually. Packages can group into two
main categories: General Purpose Packages and Special Purpose Packages
General Purpose Packages: General Purpose packages have enough features to
accomplish a wide variety of tasks. A full featured word processing program like
MS-Word, for example can be used by a student to write a search paper or by an
office security for mailing list. The four most important types of applications
software are:
1. Word Processors: Word processors are software packages that turn a
Personnel computer into a powerful typewriting tool. Word processors are
high-tech tools used by large corporations, small businesses and schools.
They are useful for writing a report, novel, letter or any other kind of
documentation. Example of word processors is Word Perfect from Word
Perfect Corporation, Ms Word from Micro-Soft Corporation and Word
Star from Word Star international.
2. Spread Sheets: Electronic spreadsheets are package that accepts data
values and relationships in columns and rows and then allows the user to
perform operations such as calculations on these facts for analysis
purposes. Spreadsheets are commonly used in accounting, and it also has
graphics generators that take data and convert them into many types of
charts or graphics. Example is Excel, Lotus 123.
3. Database Management System: Database Management System
(DBMS) is a package that allows defining to store large amounts of data,
provide fast access to these data and prepare reports from these data.
DBMS packages are available for all sizes of machines. Examples are
Dbase from Borland International, FoxPro from Fox software, and Oracle
from Oracle Corporation.

4. Graphics Packages: Graphic packages are many kind for example
designing purposes means Desktop Publishing and numeric data
representation purposes by charts. One kind of Graphics packages are
software products that convert numeric data into pictures, which are an
ideal form of communicating ideas. They allow users to create, edit,
display and print graphic images. A desktop publishing system is a system
which computers and suitable peripherals with software to produce
attractive page layouts with pictures and text printed in a variety of
typefaces. The examples of some famous packages are Coral Draw, 3d
max studio, Photo Shop etc.
Special Purpose Packages: Special Purpose packages perform a very specific
task and cannot be changed or programmed to perform a different task. For
example, payroll package is designed to be used exclusively for payroll functions.
__________SYSTEM SOFTWARE__________
All the software used to operate and maintain computer systems are
System Software. Without system software, a computer is just an expensive hunk
of junk. It also consists of “back ground” programs that enable applications
software to run on specific set of hardware. The most important parts of any
computer’s software system are the two components of system software: the
Operating System and essential system utilities, such as backup programs (Device
drivers) or translators.
1. Operating System: Operating system is a program which acts as an
interface between a User of a computer and the computer hardware. It controls
and coordinates the overall functioning of the computer. The purpose of an
operating system is to provide an environment in which a user may execute
programs. Single tasking operating systems can run only one application program
at one time, which users find very inconvenient. Multitasking operating systems
enable a single user to work with two or more programs at once. The Popular

types of Operating are DOS (Disk Operating System), Windows Operating
System, Network Operating Systems like Windows NT, UNIX, and Sun Solaris
etc.
1. Micro-Soft DOS: The most widely used microcomputer operating system
is DOS, it is written by Micro-Soft. By using this operating system the
user can give or type commands on the command line or prompt. There
are many versions of DOS since they were first released, such as 5.1, 6.22
etc.
2. Macintosh System: In 1984, Apple Computer released first personnel
computer operating system with a graphical user interface (GUI). This
operating system is use with Apple’s Macintosh family of personnel
computers. The Macintosh’s GUI provides users with an interesting
environment, this makes it user-friendly machine.
3. Windows: The windows operating system was release by Micro-Soft;
this operating system also provides GUI and ability to run two or more
application at a same time. Mouse is the standard input device use in
windows environment. The version of windows is 3.1, 95, 97, and 98.
4. UNIX: UNIX Operating system was developed by Ken Thompson at
AT&T’s Bell Laboratories in the early 1970s. UNIX was the first
operating system with multitasking, and it was designed to work
efficiency in a secure, centrally administrated computer network. It also
support multiprocessing which increase the efficiency and speed of
processing.
5. Windows NT: Windows NT Operating system was developed by
Microsoft. It is just like Microsoft Windows means GUI (Graphical User
Interface). It also support multiprocessing which increase the efficiency

and speed of processing. There are two types of Windows NT Windows
NT Server and Windows NT Workstation. Both operating systems provide
security but NT Server is more secure Operating System. Now the updated
form of Windows NT is called Windows 2000 Family. This family of OS
is most flexible and high demandable.
6. Language Translators: Whether a person is running a program written
in programming language or using packages like MS-word excel etc, all
instructions and data must be translated into machine language. The software that
does this is called language translators. In the programming languages there are
there types of language translators:
Complier: A compiler translates the all source program into machine
form. Compilers are used to translate high-level languages into machine
form. Compilers would be use in an environment where execution speed is
important.
Interpreters: Interpreters translate a program’s one line at a same time
into machine form. Interpreters provide superior error messages than
compilers.
Assemblers: Assemblers are use with assembly language. They convert
assembly source program into machine form.
7. Device Drivers: It is type of system software, which is necessary for
devices just like sound card, VGA card, Modem, NIC for using, because this
software play important rules. We can not use the devices without this software.
SYSTEM ANALYSIS AND DESIGN
Every organization needs system, in order to run smoothly. The process of
putting system into place and continuing to maintenance or improve them is
called system development. System developments contain of five activities.

1. Preliminary investigation: A preliminary investigation is undertaken
when users note a problem or opportunity and submit a formal request for a new
system.
2. Requirements analysis: After studying the result of the preliminary
investigation , management decides to continue the development process, user
needs are studied, and then system requirements are produced.
3. System design: During system design the user requirements that
arose from analyzing the user application environment are convert into a
new system’s design.
4. System acquisition: After the system design details are resolved, such
resource needs, as specific types of hardware, software and services are
determined.
5. System implementation and maintenance: During this phase the system
is set up and run. Users are then trained on the new system. After implementation
the system is maintained, it is modified to adapt to changing user and business
needs.
PROGRAM DESIGN
Developing useful computer programs require a detailed planning. The
figure that is given below contains various steps the programmer must be
following these steps so as to write effective programs.
1. Define the problem: The first activity is to understand and define the
problem. Programmer should try to understand the problem as a whole without
going into the details of input and output layouts and the calculations.
2. Solve the problem: A procedure for solving a problem is called an
algorithm. And algorithm is a set of instructions that, if carried out result in
solution of the problem. And algorithm may be written in English or using

mathematical notation. A personnel computer programming language also used to
represent an algorithm.
3. Drawing flowcharts: At this stage, the programs draw a flowchart, an
effective plan that shows the logical structure of the programs. Flowchart is a
method of assisting the user to organize the sequence of steps and produce a
visual aid to solve a given problem.
4. Program coding: Once the problem is defined and a flowchart
drawn, coding the program is straightforward. At this stage, the programmer
must be concerned with the details of the programming language. If any word
is misspelled or any errors occur, the program will not run.
5. Testing and debugging: Vital steps in developing programs. Testing is
the process of making sure the program performs as intended and debugging is
the process of locating and removing the errors.
6. Document the program: Documentation is the process of recording
details concerning a program. Two types of documentation are used technical
documentation, which is used by computer operators to run the programs or by
analysts and programmers in case the program needs modification. This
documentation includes the statement of the problems, all flowcharts and
other material developed during the problem definition, analysis and design.
The user documentation is developed for users. In this type of documentation
show the users, in easy-to-understand terms, how the program can and should be
used.

PROGRAMMING LANGUAGES
Is a set of rules that enables instructions to be written for a computer? These
languages consist of commands that combine to form statements; statements tell
the computer what to do and when to do it.
Low-level languages: In the early days of computers, the only two languages
were used the machine and assembly languages. These languages were very
difficult to use. Machine language was the first language and it is the first
generation language, machine language instructions consist of strings of 0s and
1s. Assembly language written by Grace Hopper in 1950s, and also called the
Define Program
Solve Problem
Testing & Debug
Program
Program Coding
Draw Flow Chart
Document the program

second generation of programming language. Assembly language allows
instructions to be written in a shorthand way by using mnemonics.
High level languages: In this type of languages also called fourth generation
languages, the programmer use English like commands for programming. High
level languages also called third generation languages.
Very high level languages: This type of languages is also called fourth
generation languages (4GL). The principle behind to this type of languages is to
enable users to tell the computer what should be done rather than how something
should be done. We consider 4GL to be easy-to-learn, easy-to-use languages.
Most 4GL languages were designed for use in database environments, it requires
few instructions to perform the task/work and take less time in program
development. Shorter programs and capability and English like commands for
end-users to understand and write the programs. Example are C++ popular object-
oriented language, SQL is the most used language with relational database.
Generation Languages Period
1 Machine language 40s to 50s.
2 Assembly language 50s to 60s.
3 High-level languages 60s to 70s.
4 Very high-level language 70s to 80s.
1. Artificial Intelligence based 80s to 90s.
Languages, natural and object
Oriented languages
COMPUTER HARDWARE COMPONENTS
A computer is a programmable, multiuse machine that accepts data raw facts and
figures and processes, or manipulates, it into information we use, such as
summaries or totals. Its purpose is to speed up problem solving and increase
productivity. Computer components are divided into three categories.
1. Input Unit.
2. System Unit.
3. Output Unit.

INPUT UNIT: Input is the process of entering and translating incoming data into
machine readable form so that they can be process by the computer and output
means to display the result. Input hardware devices are classified into three
categories.
1. Punching devices e-g keyboard.
2. Pointing devices.
3. Source data-entry devices.
4. KEY BOARD: It is like a type- writer, and is very easy to use because
alphabets, numbers and special characters are marked on different keys. Some
keyboards are permanently housed with the processing units and display screen.
The keyboard is built into laptop computers or attached to desktop computers with
a cable. However, wireless keyboards are also available. Different languages have
different keyboard needs. For example English has 26 characters in its alphabets,
but traditional Chinese, used in Hong Kong and Taiwan, has 13,060 characters.
5. POINTING DEVICES: These devices control the position of the cursor
or pointer on the screen. Pointing devices includes mouse, trackball, light pen,
touch pad etc.
1. MOUSE: In most of the personnel computer systems found in
organization today, keyboard entry is supplemented by a device,
called a mouse. A mouse is a device, about the size of a deck of
playing cards that moves the cursor around the screen quickly. The
mouse became popular with the introduction of the Apple
Macintosh and its icon-based screens. The introduction of
windows and OS/2 icon-based operation systems for IBM
personnel computers has made the mouse a standard features in
these systems as well.
2. TRACK BALL: Track ball consists of a sphere resting on rollers
with only the top of the sphere exposed outside its case. Like the
mouse, a track ball makes it easy to move the cursor across the
display screen. The cursor moves in whatever direction the user

spins the sphere. Many users prefer a track ball to a mouse,
because it requires less desk space. Some manufactures are
building track ball into the keyboard section of personnel computer
systems.
3. LIGHT PEN: Light pen is use with a display device. The pen
contains a light-sensitive cell at its tip; when this tip is placed near
the screen, the computer system can determine its position. Light
Pen is often use in graphics applications in order to draw lines and
shapes on the screen.
4. TOUCH SCREEN OR PAD: Touch screen is sensitive to human
fingers, and is similar to a light pen. The computer system can
sense where the finger is pointing on the screen. Touch screens are
useful for such applications as factory work; a laborer, who may
wear gloves, can easily point to a selection on the screen. The
touch screen also useful in applications in which the operator may
be untrained, e.g. if the user is a bank customer who does not have
time to read computer instructions, a clearly labeled touch screen
will quickly get the user involved.
5. SOURCE DATA-ENTRY DEVICES: They are not keyboards or
pointing devices. Data source entry devices create machine readable data on
magnetic media or paper or feed it directly into the computer’s processor. Source
data entry devices including the following e-g Imaging devices, audio input
devices, video input devices, digital cameras, CD-ROM, Floppy drive etc.
1. IMAGING DEVICES: An imaging device is a hardware that transforms
such graphical images as drawings, photographs and maps into machine-
readable form. Image scanner is use to digitizing images such as
photographs, forms and important documents into computer memory.
Digitizing cameras, which can take pictures and store them into digital
memory?

2. VOICE INPUT DEVICES: Voice input devices consist of equipment
that is designed to recognize the human voice. This technology is not as
simple as it seems, because people often pronounce words in different
ways.
OUTPUT UNIT: Output devices translate information processed by the humans
can understand. The two principal kinds of output are softcopy (Provides by
Printers normally) and Hardcopy (Display by Monitors normally).
3. MONITORS: Monitors are use with personnel computers. It has a TV-
like screen; on screen the user can see input and computer outputs. Quality of the
monitor is often judged in terms of resolution which is a measure of the number
of picture elements, or pixels, a screen contains. A pixel is the smallest increment
of a display screen that can be controlled individually. Screens for monitor are of
two types.
(1) Cathode Ray Tube (CRT) and (2) Flat Panel Display
On CRT type of screen, a data image can be produced by moving an electron
beam across a phosphor- created screen. CRT has a display screen of 25 lines of
80 characters each. A CRT screen is reliable but it is bulky and consumes a lot of
power and that is why it is cumbersome to use it with portable computers. For
small computers and new technology monitors, flat panel display is used. It does
not have a picture tube. The most common type of flat panel display is the liquid
crystal display (LCD), which produces images by aligning molecular crystals.
TERMINAL: Terminal is a monitor with a keyboard attached to it. Terminals are
connected to the main computer through communication lines or network.
4. PRINTERS: Printers are use to take the data from computer on paper.
The most common types of printers are given below:
1. Daisy Wheel Printer: This printer is used in order to get the quality
of type found on typewriters. The daisy-wheel printer is so called

because the print mechanism looks like a daisy. This printer gives us
letter quality print but slow, typically 25-55 characters per second.
2. Dot-Matrix Printers: Dot-matrix uses printer heads containing nine
to twenty pins. These pins produce patterns of dots on the paper to
form the individual characters. Dot-matrix printers are very popular as
they are inexpensive and print speed of 100-600 characters per
second. These printers can give us draft-quality, standard quality and
near-letter quality prints.
3. Ink-Jet Printers: It is use for colors output, but black and white ink-jet
printers are also used. In this type of printers images are produced by
spraying the paper with electrically charged ink through print head. They
are very fast with speed ranging from 1200 to 6000 lines per minute.
4. Laser Printers: Works like photocopiers. Images are formed by
charging hundreds of thousands of dots with a laser beam. The advantages
of laser printers are printing in multiple fonts; multiple print sizes, and
provides high speed and out-standing graphics supports. They print very
fast at rate of approximately 12,000 lines or 437 pages per minute. In laser
printer toner drum is used.
OPTICAL CHARACTER RECOGNITION: Is refers to a variety of
technologies that use special characters and codes that are recognized by optical
means. Optical characters are designed, so that they are identifiable to both
humans and optical-scanning equipment. The characters must conform to a
particular font, wand scanners are use to read these characters. Optical codes also
know as bar codes are found on supermarket goods. These codes are often read by
passing them in front of an optical scanning station, and also read by wand
scanners.
A B C D E Optical characters 1 2 3 4 5 6

4 8 0 0 12 6 5 6
Optical Codes
PROCESSING TECHNOLOGIES
Processing hardware includes the devices that compute, compare and
perform special instructions. In a personnel computer system, the processing
device is called system unit, which contains the central processing unit (CPU) and
storage media. The central processing unit is made up of two key components, the
control unit and arithmetic-logic unit (ALU). The central processing unit (CPU) in
personnel computer is found on a single chip called a microprocessor.
Control Unit: The main function of control unit is to control the activities of the
other parts of personnel computer system. It directs the flow of data between
input/output devices and memory, and between primary memory and the
arithmetic and logic unit (ALU).
Arithmetic and logic unit: The function of arithmetic and logic unit is carry out
all the mathematical (addition, subtraction, division, multiplication etc) and
logical operations (compare, sorting etc).
Primary memory: Primary memory contains the programs and data that are read
from an input device or secondary storage device, results of programs being
processed, and output that are ready to be sent to an output device or to secondary
storage device. All personnel computer primary memory is on temporary basis, it
loses its contents when the computer’s power is shut off. There are two types of
primary memory:
 Random Access Memory (RAM): Once program, data, results,
output is stored in primary memory the CPU must be able to find them again. To

make this possible, every location in primary memory has an address. The term
“Random Access” means that the CPU can go directly to any address within the
memory and read or write data there. The amount of RAM in primary memory is
measured in kilobytes (thousands of bytes) or megabytes (millions of bytes), e.g.
a personnel computer with 640 kilobytes of RAM possesses 640,000 memory
locations, while a machine with 2 megabytes of RAM has 2,000,000 random
access addresses.
 Read only Memory (ROM): With ROM, programs are written
directly on a semiconductor chip where they can be read, but not written upon;
this written process is done when the chip is manufactured. Many manufactures
place portions of their operating systems into ROM to make them more rapidly
accessible. In personnel computer ROM is use to store the parts of the operating
system that are involved with start-up or “booting” procedures. The amount of
ROM is small, about 40 to 128 KB.
Bits: The term “bit” is a construction of the two words “binary digit”. Each
alphabetic character, digit, and special symbol use by computer is translated into a
unique configuration of 0 and 1 bits. The more bits a computer can process or
move around at a same time, the faster and more powerful it is. The number of
bits that can be process at one time is referred to as the computer’s word size. A
32-bits computer can process 32-bits at a one time within CPU, in the same way a
64-bits and 128-bits computer’s process 64 and 128 bits at a one time.
Bytes: Most computer systems translate each alphabetic, digit or special symbol
into a unique configuration of bits. Such a configuration of bit is called a byte,
e.g. in one coding scheme; the letter ‘A’ is represented by the byte 11000001. The
byte can be measure in various units, such as kilobyte (KB), megabyte (MB) and
gigabyte (GB).
EBCDIC and ASCII Coding Schemes
These binary-based codes use to represent characters in byte form on a
computer system. IBM developed Extended Binary Coded Decimal Interchange

Code (EBCDIC) for its larger systems, especially its mainframe computers.
EBCDIC uses 8 bits to a character, and represented a total of 256 characters.
American Standard Code for Information Interchange (ASCII) was developed,
through the efforts of American National Standards Institute and several other
computer manufacturers. ASCII uses 7 or 8 bits to a character and can represent
128 or 256 characters. ASCII is the code of choice for character manipulation
performed outside the IBM mainframes. These codes are shown in the following
figure:
Char EDCDIC ASCII Char EBCDIC ASCII
0 11110000 0110000 B 11000010 1000010
1 11110001 0110001 C 11000011 1000011
2 11110010 0110010 D 11000100 1000100
3 11110011 0110011 E 11000101 1000101
4 11110100 0110100 F 11000110 1000110
5 11110101 0110101 G 11000111 1000111
6 11110110 0110110 H 11001000 1001000
7 11110111 0110111 I 11001001 1001001
8 11111000 0111000 J 11010001 1001010
9 11111001 0111001 K 11010010 1001011
A 11000001 1000001 L 11010011 1001100
M 11010100 1001101 T 11100011 1010100
N 11010101 1001110 U 11100100 1010101
O 11010110 1001111 V 11100101 1010110
P 11010111 1010000 W 11100101 1010111
Q 11011000 1010001 X 11100111 1011000
R 11011001 1010010 Y 11101000 1011001
S 11100010 1010011 Z 11101001 1011010
Secondary Storage Technologies
These technologies store data on permanent bases. These technologies are slower
and less expensive than primary memory.
Diskettes: Diskettes or floppy disks are the most common storage media in
microcomputer. Diskettes are available in diameters of 5 inches and 3 inches.
Density refers to the number of bits packed on the surface of diskettes. The most
common grades of density are double-density and high-density. High-density 3

inches diskettes hold 1.44MB of data and double-density 3 inches diskettes can
hold 720KB of data. The high-density 5 inches diskettes hold 1.2MB of data,
whereas the double-density 5 inches diskettes can hold 320KB of data.
Winchester Disks: Winchester disk contains one or more hard disks, and
accesses mechanism (read/write heads). Data is store on the disk surface along
tracks. These tracks are divided into sectors, and read/write heads are use to store
and retrieve data. Winchester is sealed in a case, because it is protected and free
from air; it can rotate at higher rates of speed. Winchester disk is internal and fit
within the computer system unit. Winchester disks capacity measure in megabyte
(MB) and gigabyte (GB), 250MB, 10GB, and 15GB etc.
CD-ROM (Compact disk, read-only memory): Most computers today use CD-
ROM and also called “write once, read many” memory. It can store text, data, and
graphics, audio and video images. CD-ROM work through laser technology, high
laser beams are use to write, and low laser beams enable the disk to be read. CD-
ROM is slower than magnetic disk.
Prepared By Amjad Khan Aridi
Date: 4th Oct,2017

HISTORY OF COMPUTER

More Related Content

What's hot

Similar to HISTORY OF COMPUTER

More from Amjad Khan Afridi

Recently uploaded

HISTORY OF COMPUTER