detailed ppt for basics of computers

1. Basic Concepts of Computer
Computer is an electronic device which is used to store the data, as per given instructions
it gives results quickly and accurately.
Data : Data is a raw material of information.
Information : Proper collection of the data is called information.
Characteristics of Computer
SPEED : In general, no human being can compete to solving the complex computation, faster
than computer.
ACCURACY : Since Computer is programmed, so what ever input we give it gives result with
accurately.
STORAGE : Computer can store mass storage of data with appropriate format.
DILIGENCE : Computer can work for hours without any break and creating error.
VERSATILITY : We can use computer to perform completely different type of work at the
same time.
POWER OF REMEMBERING : It can remember data for us.
NO IQ : Computer does not work without instruction.
NO FEELING : Computer does not have emotions, knowledge, experience, feeling.

2. The characteristics of computers that have made them so powerful and universally useful are
speed, accuracy, diligence, versatility and storage capacity. Let us discuss them briefly.
Speed
Computers work at an incredible speed. A powerful computer is capable of performing about 3-
4 million simple instructions per second.
Accuracy
In addition to being fast, computers are also accurate. Errors that may occur can almost always
be attributed to human error (inaccurate data, poorly designed system or faulty
instructions/programs written by the programmer)
Diligence
Unlike human beings, computers are highly consistent. They do not suffer from human traits of
boredom and tiredness resulting in lack of concentration. Computers, therefore, are better than
human beings in performing voluminous and repetitive jobs.
Versatility
Computers are versatile machines and are capable of performing any task as long as it can be
broken down into a series of logical steps. The presence of computers can be seen in almost
every sphere – Railway/Air reservation, Banks, Hotels, Weather forecasting and many more.
Storage Capacity
Today’s computers can store large volumes of data. A piece of information once recorded (or
stored) in the computer, can never be forgotten and can be retrieved almost instantaneously.

3. Computers can be generally classified by size and power as follows, though there is
considerable overlap:
Personal computer: A small, single-user computer based on a microprocessor.
Workstation: A powerful, single-user computer. A workstation is like a personal computer,
but it has a more powerful microprocessor and, in general, a higher-quality monitor.
Minicomputer: A multi-user computer capable of supporting up to hundreds of users
simultaneously.
Mainframe: A powerful multi-user computer capable of supporting many hundreds or
thousands of users simultaneously.
Supercomputer: An extremely fast computer that can perform hundreds of millions of
instructions per second.

4. The abacus (plural abaci or abacuses), also called a counting frame, is a calculating tool
that was in use centuries before the adoption of the written modern numeral system and is
still widely used by merchants, traders and clerks in Asia, Africa, and elsewhere. Today,
abaci are often constructed as a bamboo frame with beads sliding on wires, but originally
they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal.
The user of an abacus is called an abacist.

5. Pascal's calculator
Blaise Pascal was the inventor of the mechanical calculator in the early 17th century. Pascal
designed the machine in 1642. He was spurred to it when participating in the burden of
arithmetical labor involved in his father's official work as supervisor of taxes at Rouen.First
called the Arithmetic Machine, Pascal's Calculator and later Pascaline, his invention was
primarily intended as an adding machine which could add and subtract two numbers directly
although its description could be extended to a "mechanical calculator with which it was
possible to multiply and divide by repetition."
Pascal went through 50 prototypes before presenting his first machine to the public in 1645.
He dedicated it to Pierre Séguier, the chancellor of France at the time. He built around twenty
more machines during the next decade, often improving on his original design. Nine machines
have survived the centuries,[ most of them being on display in European museums. In 1649
a royal privilege, signed by Louis XIV of France, gave him the exclusivity of the design and
manufacturing of calculating machines ...

6. Charles Babbage, 26 December 1791 –18 October 1871) was an English polymath.[1] A
mathematician, philosopher, inventor and mechanical engineer, Babbage is best
remembered for originating the concept of a programmable computer.
Considered a "father of the computer",[2] Babbage is credited with inventing the
first mechanical computer that eventually led to more complex designs. His varied work in
other fields has led him to be described as "pre-eminent" among the many polymaths of
his century.[1]
Parts of Babbage's uncompleted mechanisms are on display in the London Science
Museum. In 1991, a perfectly functioningdifference engine was constructed from
Babbage's original plans. Built to tolerances achievable in the 19th century, the success of
the finished engine indicated that Babbage's machine would have worked.
A difference engine is an automatic mechanical calculator designed to tabulate polynomial
functions. The name derives from the method of divided differences, a way to interpolate
or tabulate functions by using a small set of polynomial coefficients. Most mathematical
functions commonly used by engineers, scientists and navigators, including logarithmic
and trigonometric functions, can be approximated by polynomials, so a difference engine
can compute many useful tables of numbers.
The historical difficulty in producing error-free tables by teams of mathematicians
and human "computers" spurred Charles Babbage's desire to build a mechanism to
automate the process.

7. ENIAC
Short for Electronic Numerical Integrator And Calculator, the ENIAC was the first electronic
computer used for general purposes, such as solving numerical problems. It was invented
by J. Presper Eckert and John Mauchly at the University of Pennsylvania in an effort to
calculate artillery firing tables for the United States Army's Ballistic Research Laboratory.
Its construction began in 1943 and was not completed until 1946. The ENIAC occupied
about 1,800 square feet, used 17,468 vacuum tubes, 15,000 relays, weighed almost 50
tons, uses 200 kilowatts of electricity, and cost about $500,000. Although it was not
completed until the end of the World War II, the ENIAC was created to help with the war
effort against German forces.
All of the wires, switches and components are part of the ENIAC with two of the team of
operators helping run the machine. The ENIAC is now being displayed at the Smithsonian
Institution in Washington D.C. In 1996, the U.S. Postal Services released a new stamp
commemorating the 50th birthday of the ENIAC.

8. UNIVAC
Short for Universal Automatic Computer, the UNIVAC I, a trademark of the
Unisys corporation, was released in 1951 and 1952 when first developed by J. Presper
Eckert and John Mauchly. The UNIVAC is an electrical computer containing thousands of
vacuum tubes that utilizes punch cards and switches for inputting data and punch cards for
outputting and storing data. The UNIVAC was later released the UNIVAC II, and III with
various models, such as the 418, 490, 491, 1100, 1101, 1102, 1103, 1104, 1105, 1106, 1107,
and 1108. Many of these models were only owned by a few companies or government
agencies.

9. 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.

10. Advantages
Vacuum tubes were the only electronic component available during those days.
Vacuum tube technology made possible to make electronic digital computers.
These computers could calculate data in millisecond.
Disadvantages
The computers were very large in size.
They consumed a large amount of energy.
They heated very soon due to thousands of vacuum tubes.
They were not very reliable.
Air conditioning was required.
Constant maintenance was required.
Non-portable.
Costly commercial production.
Limited commercial use.
Very slow speed.
Limited programming capabilities.
Used machine language only.
Used magnetic drums which provide very less data storage.
Used punch cards for input.
Not versatile and very faulty.

11. 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 languageswere 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.

12. Advantages
Smaller in size as compared to the first generation computers.
The 2nd generation Computers were more reliable
Used less energy and were not heated.
Wider commercial use
Better portability as compared to the first generation computers.
Better speed and could calculate data in microseconds
Used faster peripherals like tape drives, magnetic disks, printer etc.
Used Assembly language instead of Machine language.
Accuracy improved.
Disadvantages
Cooling system was required
Constant maintenance was required
Commercial production was difficult
Only used for specific purposes
Costly and not versatile
Puch cards were used for input.

13. 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 andmonitors 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.

14. Advantages
Smaller in size as compared to previous generations.
More reliable.
Used less energy
Produced less heat as compared to the previous two generations of computers.
Better speed and could calculate data in nanoseconds.
Used fan for heat discharge to prevent damage.
Maintenance cost was low because hardware failure is reare.
Totally general purpose
Could be used for high-level languages.
Good storage
Versatile to an extent
Less expensive
Better accuracy
Commercial production increased.
Used mouse and keyboard for input.
Disadvantages
Air conditioning was required.
Highly sophisticated technology required for the manufacturing of IC chips.

15. 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 ofGUIs, the mouse and handheld devices.

16. Advantages
More powerful and reliable than previous generations.
Small in size
Fast processing power with less power consumption
Fan for heat discharging and thus to keep cold.
No air conditioning required.
Totally general purpose
Commercial production
Less need of repair.
Cheapest among all generations
All types of High level languages can be used in this type of computers
Disadvantages
The latest technology is required for manufacturing of Microprocessors.

17. 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 andnanotechnology 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.

18. Computer and its components
Computer : Computer itself a combination of different type of separate electronic device. i.e.
Computer only will be computer if it has INPUT DEVICE, PROCESS UNIT, and OUTPUT DEVICE.
Central Processing Unit (CPU) : It is heart and mind of the computer without this unit
computer unable to process.
Keyboard : This is an input device which is used to input the data into the computer.
Mouse : This is also an input device which is used to input the data into the computer.
Monitor : This is an output device which is used to show the result of the instructions.
There are variety of monitor available in the market such as, CRT Monitor, LCD Monitor, Touch
Screen Monitor, TFT Monitor etc.
Switched Mode Power Supply (SMPS) : This is and electronic device which is used to manage
the power supply of computer.
Hard Disk (HDD) : This is used to store the data in massive amount. There are so many type of
HDD available in the market, i.e. SATA, PATA, External HDD, Internal HDD.
Printer : This is an out put device which is used to show the result on the paper. There are
plenty of printer available in the market like inkjet, Laser printer, dot matrix printer etc.
Universal Serial Bus (USB) : This is used to connect the external device to the computer.
Ethernet Cable : This is used to connect computer with other computer.
CD/DVD ROM : This is used to store the data.
.

19. Speaker : This is an output device which is used to listen voice, songs, etc.
Mike : This is an Input device which is used to record the sound .
Laptop : This is complete computer which can be carried anywhere any time.
Notebook : This is called mini laptop which is generally lighter and smaller than laptop.
Random Access Memory (RAM) : This is called primary memory. This is also called main memory
of the computer. Whatever data is written in this memory, is lost after switching off the system.
Read Only Memory (ROM) : This is called primary memory. Data is written in this memory by the
vendor of the computer permanently.
Pen Drive : This is very popular device now a days for carrying data on move.
Blue Ray Disk : This is same as CD/DVD but only different is it can store multi time of data from
CD/DVD and faster than CD/DVD.
Scanner : This is an input device which is used to scan the document for the soft copy.
LCD : It is known as Liqued Crystal Display. It is an output device as monitor.
Motherboard : It is a combination of electronic circuits.
Sound Card : This is also a combination of electronic circuits which helps to give out put in the
form of sound.
Graphics Card : This is also a combination of electronic circuits which helps to give output the
data into the monitor

20. Advantages of Computer
Computer has made a very vital impact on society. It has changed the way of life. The use of
computer technology has affected every field of life. People are using computers to perform
different tasks quickly and easily. The use of computers makes different task easier. It also
saves time and effort and reduces the overall cost to complete a particular task.
Many organizations are using computers for keeping the records of their customers. Banks
are using computers for maintaining accounts and managing financial transactions. The
banks are also providing the facility of online banking. The customers can check their account
balance from using the internet. They can also make financial transaction online. The
transactions are handled easily and quickly with computerized systems.
Disadvantages of computer
The use of computer has also created some problems in society which are as follows.
Unemployment
Different tasks are performed automatically by using computers. It reduces the need of
people and increases unemployment in society.
Wastage of time and energy
Many people use computers without positive purpose. They play games and chat for a long
period of time. It causes wastage of time and energy. Young generation is now spending
more time on the social media websites like Facebook, Twitter etc or texting their friends all
night through smartphones which is bad for both studies and their health. And it also has
adverse effects on the social life.

21. Data Security
The data stored on a computer can be accessed by unauthorized persons through networks.
It has created serious problems for the data security.
Computer Crimes
People use the computer for negative activities. They hack the credit card numbers of the
people and misuse them or they can steal important data from big organizations.
Privacy violation
The computers are used to store personal data of the people. The privacy of a person can be
violated if the personal and confidential records are not protected properly.
Health risks
The improper and prolonged use of computer can results in injuries or disorders of hands,
wrists, elbows, eyes, necks and back. The users can avoid health risks by using the computer
in proper position. They must also take regular breaks while using the computer for longer
period of time. It is recommended to take a couple of minutes break after 30 minutes of
computer usage.
Impact on Environment
The computer manufacturing processes and computer waste are polluting the environment.
The wasted parts of computer can release dangerous toxic materials. Green computer is a
method to reduce the electricity consumed and environmental waste generated when using
a computer. It includes recycling and regulating manufacturing processes. The used
computers must be donated or disposed off properly.

22. Operating System is a software program that acts as an interface between the user and the
computer. It is a software package which allows the computer to function.
Functions:
Program creation
Program execution
Access to Input/Output devices
Controlled access to files
System access
Error detection and response
Interpreting the commands
Managing peripherals
Memory management
Processor management
Information management
Process communication
Netoworking
Types of Operating System
DOS (Disk Operating System)
UNIX
LINUX
Windows
Windows NT

23. The operating system is the most important program that runs on acomputer. Every general-
purpose computer must have an operating system to run other programs and applications.
Operating systems perform basic tasks, such as recognizing input from the keyboard,
sending output to the display screen, keeping track of files and directories on the disk, and
controlling peripheral devices such as disk drives and printers.
For large systems, the operating system has even greater responsibilities and powers. It is like a
traffic cop -- it makes sure that different programs and users running at the same time do not
interfere with each other. The operating system is also responsible for security, ensuring that
unauthorized users do not access the system

24. Introduction to DOS / WINDOWS
Though UNIX was a powerful operating system available, but it was not suitable for 8-bit
8086 microprocessor based Personal Computers. So there was a need for a small operating
system that could work in 640K memory(RAM). DOS was an variant of CP/M (Control
Program/Monitor) which ran for the first time on IBM-PC in 1981. It is called so because it
resides on Floppy or Hard disk and provides command level interface between user and the
computer hardware. The different versions of MS-DOS have evolved over a period of time
with Microsoft introducing new features in each new releases. Starting with MS-DOS1.1, the
latest version was MS-DOS6.22 released in 1994. There are various versions of DOS like MS-
DOS(Microsoft), PC-DOS(IBM), Apple DOS, Dr-DOS etc.
WINDOWS was similar to APPLE Mach operating system interface on IBM-PC. The main
features of windows are easy to use graphical user interface (GUI), device independent
graphics and multitasking support. The first version of windows1.0 was introduced in 1985.
Windows was an application of MS-DOS using the basic commands of DOS. Windows for
Workgroup (WIN3.11) released in 1992 was an integrated windows and networking package
with file and printer sharing capabilities, a network mail (Microsoft Mail) and a workgroup
scheduler (Schedule+) packages in windows environment. WINDOWS-95 released in 1995 is
a 32-bit operating system which includes MS-DOS7.0 and takes control of computer system
after starting.

26. The CPU is centrally located on the motherboard. Since the CPU carries out a large share of
the work in the computer, data pass continually through it. The data come from the RAM and
the units (keyboard, drives etc.). After processing, the data is send back to RAM and the units.
The CPU continually receives instructions to be executed. This is the basic principle of what
takes place within most data processing units, even if the outcome is very different. In a
mobile phone, for example, data from the SIM card will be submitted via the CPU, whereas on
a games console, it will be actions send via the controller. Each instruction is a data processing
order. This information instructs the CPU on how this data should be processed, as well as the
value of the data itself.

27. An arithmetic logic unit (ALU) is a digital circuit used to perform arithmetic and logic
operations. It represents the fundamental building block of the central processing unit
(CPU) of a computer. Modern CPUs contain very powerful and complex ALUs. In addition to
ALUs, modern CPUs contain a control unit (CU).
Most of the operations of a CPU are performed by one or more ALUs, which load data from
input registers. Aregister is a small amount of storage available as part of a CPU. The control
unit tells the ALU what operation to perform on that data and the ALU stores the result in an
output register. The control unit moves the data between these registers, the ALU, and
memory.
How an ALU Works
An ALU performs basic arithmetic and logic operations. Examples of arithmetic operations
are addition, subtraction, multiplication, and division. Examples of logic operations are
comparisons of values such as NOT, AND, and OR.
All information in a computer is stored and manipulated in the form of binary numbers, i.e.
0 and 1.Transistor switches are used to manipulate binary numbers since there are only two
possible states of a switch: open or closed. An open transistor, through which there is no
current, represents a 0. A closed transistor, through which there is a current, represents a 1.

28. A control unit is circuitry that directs operations within a computer's processor. It lets the
computer's logic unit, memory, as well as both input and output devicesknow how to
respond to instructions received from a program. Examples of devices that utilize control
units include CPUs and GPUs.
A control unit works by receiving input information that it converts into control signals,
which are then sent to the central processor. The computer's processor then tells the
attachedhardware what operations carry out. The functions a control unit performs
depend on the type of CPU, due to the variance of architecture between different
manufacturers. The following diagram illustrates how instructions from a program are
processed.

29. Memory speeds and compatibility
Memory is designed to be backward-compatible, so generally speaking, you can safely
add faster memory to a computer that was designed to run slower memory. However,
your system will operate at the speed of the slowest memory module.
One thing to keep in mind is that the memory does need to be the same type - for
example, SDRAM cannot be mixed with DDR, and DDR cannot be mixed with DDR2 and
DDR2 cannot work in a DDR3 system.
We recommend that you use the Crucial Memory Advisor™ or System Scanner tools to
find the right memory for your computer. Rather than give memory modules catchy
names, the industry refers to modules by their specifications. But if you don't know a lot
about memory, the numbers can be confusing. Here's a short summary of the most
popular types of memory and what the numbers refer to.
Double data rate synchronous dynamic random-access memory (DDR SDRAM) is a class
of memory integrated circuits used in computers. DDR SDRAM, also called DDR1 SDRAM,
has been superseded by DDR2 SDRAM, DDR3 SDRAM and DDR4 SDRAM.