A computer is a machine that performs mathematical and logical calculations using electricity and electronics. Early computers were enormous machines that filled entire rooms and used vacuum tubes. Advances like integrated circuits, transistors, and microchips made computers smaller and more accessible. Now, computers contain components like CPUs, memory, storage drives, and peripherals inside their cases. Hardware is the physical components while software is abstract computer code.

1. What is a computer Simply put, a computer is a machine that performs mathematical and logical
calculations. Brief History
A large computer used in the 1940's. Computers, by our above definition, have been around for
thousands BASIC OF COMPUTER
of years. One of the earliest computers was the abacus, a series of beads arranged on metal rods.
Beads could be slid back and forth to operate on numbers. This was a very rudimentary device
and is not commonly thought of as a computer in modern times. Our idea of computers involves
electricity and electronics. Electricity makes computers much more efficient. The first computers
used an incredible amount of electricity, which changed voltages in vacuum tubes to operate the
computer. These computers were given instructions using punch cards, and were behemoths,
taking up entire floors of buildings. Only the more privileged universities and government
facilities had access to them. In the 1960's, the vacuum tube was replaced by the integrated
circuit and transistor. These greatly reduced the size and power consumption of computers. They
were still very large by today's standards, but more institutions had access to computing power
than ever before. At the end of the decade, the microchip was invented, which reduced the size of
the computer even more. By the end of the 1970's, computers were widespread in businesses.
Using a computer involved typing on a terminal (a keyboard and monitor connected to a large
central computer). Soon, parts became small enough to allow many users to have a computer at
their home. Thus the Personal Computer, or PC, was born. Since then, personal computer has

2. have become tremendously more efficient. They are much smaller, and yet have seen extreme
performance gains. In addition to these improvements, computers have become affordable
enough for many families worldwide. Hardware Hardware is the stuff you can touch, as opposed
to software which is abstract and exists only in a virtual world as computer code. Hardware is
made of materials found in the universe and are subject to the laws of physics. Contrary to the
latter, software is bound only by the creator's imagination and the user's willingness to believe
what the creator wants them to. The Insides Inside the computer case are various components
that allow the computer to run.
SSD The SSD, or otherwise known as a Solid State Drive, is a storage device using RAM
modules instead of a spinning disk. These storage devices are much faster than HDDs because
they don't have to spin up. The SSD can have transfer speeds up to 10x as fast because of this.
CPU
Several CPU microchips. The Central Processing Unit, or CPU, does nearly all the calculating. It
is the main microchip in the computer that distributes tasks to all other parts of the computer.
When most people talk about the processor, or chip, it is actually the CPU they are referring to.
Memory RAM (Random Access Memory), commonly called just memory, holds computer code
that needs to be operated on quickly. RAM is plugged into special slots on the motherboard.
There is a large link (known as a bus) from the memory to the CPU, allowing information held in
memory to quickly interact with the CPU. The amount of RAM available is limited and therefore
needs to be constantly cleared and refilled (don't worry; all computers do this automatically).
RAM is just one part of the computer that determines your speed.
RAM is referred to as "volatile" memory because the information stored in it disappears when
the power is turned off. Hard drives and flash drives, on the other hand, contain non-volatile
memory, which is like paper: it can be destroyed or erased, but when properly taken care of, can
last forever.
Hard Drive

3. A partially dismantled hard drive, showing the disc inside. The hard drive is the main storage
area in the computer. It is usually where you put your data to be stored permanently (until you
choose to erase it), and it retains data after power is removed. Virtually all of your data is stored
on your hard drive. A hard drive is composed of disk(s), where the data is recorded onto the
surface, similar to records, CDs, and DVDs. The size of the hard drive (today's are usually in
gigabytes) is determined by how dense (small) the recording is. Many of today's major programs
(such as games and media creating and editing programs like Photoshop) and files (such as
pictures, music, or video) use a considerable amount of space. Most low-end computers, as of
2011, are shipped with a 160GB (gigabyte) or larger hard drive. Currently, in 2014, it is common
to find desktop computers with 1000GB (1 Terabyte) hard drive. As an example, an average
.mp3 file takes between 7.5 and
15MB (megabytes) of space. A megabyte is 1/1024th of a gigabyte, thus allowing most new
computers to store thousands of such files. Users who wish to store a lot of media on a computer
will want a larger hard drive, as will users who want to store numerous large programs, like
modern games, which require a lot of space. Most video games today are distributed via DVD
discs that store data, called DVD-ROM (read only memory, which can be read off the disk, but
not modified), which can be anywhere from 4.7GB for a single layer disk to 8.5GB for a double
layered disk...and many large programs are already taking up more than one disk. Another
concern for users who want higher performance is hard drive speed, measured in RPM (rotations
per minute). Most desktop hard drives today are 7200RPM models, with lower end 4200RPM
models not commonly seen in new systems (other than laptops), and higher end 10,000RPM hard
drives generally seen only in gaming and other extremely high performance computers due to
their cost. For example, a 1TB 7200RPM drive costs around 85$ (as of January, 2011), while a
300GB 10,000RPM drive costs almost 300$ (as of February 2011). Hard drives are constantly
increasing in size, both because technology allows, and because of demand for more storage
space. For example, an Apple iMac in the late nineties shipped with a 4GB hard drive, and sold
for 1,300$ US (although it should be noted that the cost alone is not indicative of the hard drive,
or vice versa), compared to a modern iMac which sells for 1000$ US and carries a 160GB hard
drive(As of April 2007). Compare to the original IBM PC, which carried only a 10MB hard
drive, or 10/1024th of a GB. Some high end computers already have more than 2 Terabytes, and

4. within decades Petabytes (thousands of Terabytes) and even exobytes (Thousands of Petabytes)
will not be unheard of.
The Peripherals Peripherals are hardware attached to a computer, but external to the main case
that houses the CPU, Hard drives, and other such equipment. They are basically devices that
allow people to communicate to the computer. It is generally a good idea, although not as
important as it used to be, to add and remove hardware from the computer while it is turned off.
Things such as USB storage devices and keyboards/mice can generally be inserted and removed
at a whim with no consequence, however more advanced things such as printers should be
installed according to the manufacturer's instructions, which may include shutting down your
computer. Keyboard and Mouse The keyboard and mouse are basic input devices.
A keyboard with a QWERTY layout. The keyboard has keys that, when pressed, send
information to the computer. The keyboard is the most widely used device for interacting with a
computer, and even many modern operating systems, such as Microsoft Windows XP can be
operated with nothing but the keyboard or little but the keyboard. The most commonly used
keyboard, by far, is the QWERTY layout, which almost all keyboards sold use. This is the same
layout as most typewriters sold within the last century. The second most common, but a very
distant follower, is the Dvorak Simplified Keyboard. While this is technically better, the industry
and consumer market as a whole has mostly rejected it.
The QWERTY keyboard was designed to prevent typewriters from jamming while keys were
being pushed at a fast rate, by keeping keys as far apart as possible. The Dvorak keyboard layout
was designed for computers, where this is obviously not a problem, and thus places the most
commonly used keys where they are easy to reach, and because of that, quicker. However,
because of the popularity QWERTY had, the Dvorak keyboard layout never became popular, for
two main reasons. The first being that because most people already know how to use QWERTY
keyboards, and people are thus unlikely to switch, and the second being that because most people
know how to use a QWERTY keyboard, there is very little use of Dvorak. It is generally advised
that you use a QWERTY keyboard, as even though Dvorak users gain significantly faster typing
speeds, the rarity of the layout makes it hard for people who use Dvorak to use most other
computers. Keyboards vary in appearance. Those attached to a desktop computer are frequently
large with an additional number pad built in on the right side, while laptop keyboards are
attached to the computer and are often much smaller. Some keyboards also offer special buttons
to control the mouse on the screen or to play music.

5. A three button mouse. The mouse is an input device which is primarily used by physically
moving the device across a surface, which causes a pointer symbol, called a "cursor", to move
across the screen, and secondarily by pressing a button while the cursor is over an
object on the monitor, or "clicking". All mice have at least one button, with the most common
ouse known to
most people which uses a single button. This button is usually activated by pushing on the front
of the mouse, or pushing the entire mouse down. This has the benefit of being a simpler
interface, and arguably more attractive, but suffers from this of being slightly more of a hassle to
use, with tradition "right click" needs being changed to pressing a "control" or "ctrl" key on the
keyboard while pressing the main button. These are only used with Macintosh OS, such as Mac
ce: The second most common layout, more common in older computers,
which has a button on the left and right, usually for the index and middle finger. While less
useful than a three button mouse, they are, when teamed with a standard keyboard, capable of
pe
Fundamentally the same as a two button mice, but with a third button added between the "left"
and "right" click buttons. While the mouse technically has three buttons, this may be confusing
to some users, as the "middle"/"center" click button is also a scroll wheel. This design allows the
user to scroll through documents, make selections, and do other tasks by moving a finger, rather
than pressing an arrow key or "Page up/Page down" key on a keyboard.
The center button can also be press inwards to create a "middle click" button, which although
not common, is used in some programs to perform a simple function, such as the Firefox web
browser, which uses the middle click to open
Usually seen only on gaming and multimedia specialization mice, extra buttons generally do not
serve any native purpose, and rather are assigned a function to perform by the user. For example,
a user who
uses the mouse to play games might assign the additional buttons to switch between weapons in
a shooter, or cast spells in a fantasy game. There are two other major differences in mice, which
is Optical/Laser mice, and Ball mice. This is how the mice tells where it is, with the laser
measuring the distance it crosses when it is moved, and the ball measuring how it rotates. The
laser is generally more accurate and less of a hassle to use, and can be used on more surfaces, but
the ball mouse is cheaper. Ball mice are rarely seen today.

6. The last important consideration when buying a mouse is size. You should always try to put
your hand on a mouse and move it around, to see how well it feels in your hand. If it feels
awkward, small, big, long, or short, look for something better! Not only will your hands thank
you, but you will be more efficient. Media Devices (Floppy, CD-ROM, DVD, USB) These
devices carry data, in the same way that a hard drive does, but are much more portable. They are
the primary method of storing data outside of a computer, and the main method of transferring
information between computers without the use of a network, such as the internet. There are
-ROM: Capable of storing 700MB of data, CDs
have been the most common method of storing data for most of the last decade or so. They are
of data in their single layer form and 8.5GB in their double layer form, they are the most
not usually used by commercial software, USB 'sticks' and Flash 'cards' have become popular
ways of storing data because of their ease of use and low cost. While sizes range from 2GB on
old units to 256GB on larger, more expensive modern units, the average stick today is 4 or 8GB,
with an average 4GB USB stick costing about 15$ US.
The floppy disk has been phased out. Monitor The monitor is the main method for the computer
to produce output, in the same way a book has pages. A book filled with letters, but in a way you
can't possible understand or even see is of no use to you, and the same is true for a computer.
While older monitors, CRTs, were rather bulky like TVs, newer monitors, or LCDs, are much
more compact, and can be easily lifted. For much of the history of computers, the most common
monitors were CRTs, short for Cathode Ray Tubes. They work on the same principle as a
television. They were generally heavy, had a lower image quality, and were in general less
reliable than an LCD. They come in two forms, the normal version, which has a curved monitor,
and "Flat Screen", where the display is completely level (although it still has the bulky back
end). It is suggested that if you plan to remove a CRT, it is better for the environment to safely
dispose of it (not just into a bin, an electronic waste bin), as CRT's contain high levels of toxic
chemicals. The most common type of monitor today is an LCD, or Liquid Crystal Display, which
is much lighter, although slightly more expensive. They have a smaller form, a higher image
quality, and are overall better than CRT monitors. Tip: To take proper care of your monitor,
always be sure that the screen is not left on a static image for long periods of time. This can
"burn" the image into the monitor, meaning that it will have a ghosting effect, even when that
image is not displayed. This can not only be highly annoying, but in some cases, make it so the
monitor needs to be replaced. To avoid this, either set a moving screensaver, which will trigger
after a set amount of time, or simply turn the monitor off Printer If you have a printer attached to
your computer you can print your information and keep a physical copy of data. Depending on
what type of printer you have, you can
print in color, double-sided or book form. The output quality of some printers goes from draft (to
save ink) all the way to photo quality. Printers come in all price ranges and in many types. The
most common for home use are ink jets (bubble jets) and laser. There are specialized printers for
data plotting (mapping), photos only, labels and more.

7. A lot of printers are "all-in-ones" which simply means they combine more than one function.
They can be any combination of printer, copier, fax and scanner. If you are looking to buy an all-
in-one make sure it has all the features you are looking for. You don't want to get it home and
find out you still need a separate fax machine or scanner that you thought was included!
Software What is Software? Computer software, or simply software, also known as computer
programs, is the non-tangible component of computers. Computer software contrasts with
computer hardware, which is the physical component of computers. Computer hardware and
software require each other and neither can be realistically used without the other. Computer
software includes all computer programs regardless of their architecture; for example, executable
files, libraries and scripts are computer software. Yet, it shares their mutual properties: software
consists of clearly-defined instructions that upon execution, instructs hardware to perform the
tasks for which it is designed. Software is stored in computer memory and cannot be touched,
just as a 3D model shown in an illustration cannot be touched.[1] At the lowest level, executable
code consists of machine language instructions specific to an individual processor – typically a
central processing unit (CPU). A machine language consists of groups of binary values
signifying processor instructions that change the state of the computer from its preceding state.
For example, an instruction may change the value stored in a particular storage location inside
the computer – an effect that is not directly observable to the user. An
instruction may also (indirectly) cause something to appear on a display of the computer system
– a state change which should be visible to the user. The processor carries out the instructions in
the order they are provided, unless it is instructed to "jump" to a different instruction, or
interrupted. Software is usually written in high-level programming languages that are easier and
more efficient for humans to use (closer to natural language) than machine language.[2] High-
level languages are compiled or interpreted into machine language object code. Software may
also be written in a low-level assembly language, essentially, a vaguely mnemonic representation
of a machine language using a natural language alphabet. Assembly language is converted into
object code via an assembler. TYPES OF SOFTWARE
Application software uses the computer system to perform useful work or provide
entertainment functions beyond the basic operation of the computer itself. System software is
designed to operate the computer hardware, to provide basic functionality, and to provide a
platform for running application software.[3] System software includes: Operating system,
an essential collection of computer programs that manages resources and provides common
services for other software. Supervisory programs, boot loaders, shells and window systems are
core parts of operating systems. In practice, an operating system comes bundled with additional
software (including application software) so that a user can potentially do some work with a
computer that only has an operating system. Device driver, a computer program that
operates or controls a particular type of device that is attached to a computer. Each device needs
at least one corresponding device driver; thus a computer needs more than one device driver.
Utilities, software designed to assist users in maintenance and care of their computers.
Malicious software or malware, computer software developed to harm and disrupt computers. As
such, malware is undesirable. Malware is closely associated with computer-related crimes,
though some malicious programs may have been designed as practical jokes.
Nature, or domain of execution

8. Desktop applications such as web browsers and Microsoft Office, as well as smartphone and
tablet applications (called "apps"). Server software Scripts, such as JavaScript scripts are
pieces of software traditionally embedded in web pages that are run directly inside the web
browser when a web page is loaded, without the need for a web browser plugin. Software written
in other programming languages can also be run within the web browser if the software is either
translated into JavaScript, or if a web browser plugin that supports that language is installed; the
most common example of the latter is ActionScript scripts, which are supported by the Adobe
Flash plugin. Web applications usually run on the web server and output dynamically-
generated web pages to web browsers, using e.g. PHP, Java or ASP.NET, or even JavaScript that
runs on the server; in modern times they commonly include some JavaScript to be run in the web
browser as well, in which case they typically run partly on the server, partly in the web browser.
Plugins and extensions are software that extends or modifies the functionality of another piece of
software, and require that software be used in order to function; Embedded software resides as
firmware within embedded systems, devices dedicated to a single use or a few uses such as cars
and televisions (although some embedded devices such as wireless chipsets can themselves be
part of an ordinary,
non-embedded computer system such as a PC or smartphone).[4] In the embedded system
context there is sometimes no clear distinction between the system software and the application
software. However, some embedded systems run embedded operating systems, and these
systems do retain the distinction between system software and application software (although
typically there will only be one, fixed, application which is always ran). Microcode is a special,
relatively obscure type of embedded software which tells the processor itself how to execute
machine code, so it is actually a lower level than machine code.[5] It is typically proprietary to
the processor manufacturer, and any necessary correctional microcode software updates are
supplied by them to users (which is much cheaper than shipping replacement processor
hardware). Thus an ordinary programmer would not expect to ever have to deal with it.
Programming tools Main article: Programming tool Programming tools are software in the form
of programs or applications that software developers (also known as programmers, coders,
hackers or software engineers) use to create, debug, maintain (i.e. improve or fix), or otherwise
support software. Software is written in one or more programming languages; there are many
programming languages in existence, and each has at least one implementation, each of which
consists of its own set of programming tools. These tools may be relatively self-contained
programs such as compilers, debuggers, interpreters, linkers, and text editors, that can be
combined together to accomplish a task, much as one might use multiple hand tools to fix a
physical object, or they may be an integrated development environment (IDE), which combines
much or all of the functionality of such self-contained tools. An IDE may do this either by
invoking the relevant individual tools on behalf of the programmer, or by reimplementing their
functionality in a new way. Almost all programming language implementations (a notable
exception being Smalltalk) provide the option of using individual tools rather than an IDE,
because some programmers prefer not to use IDEs for various
reasons, and IDEs usually take longer to be developed to an "acceptable" standard than
individual tools - indeed, initially, new programming languages (which are created every year)
would not typically have IDEs available for them. Setup and Boot The first thing to do after
taking your computer out of the box is to set it up. While many stores offer at home installation,
this is generally unneeded for anyone able to operate a computer, as a computer can be hooked

9. Also known as the 'tower', or incorrectly as the 'CPU', the case is what stores all of the brains of
the computer- the graphics card, processor, hard drives, etc. This is the most important and
keyboard/mouse the fans do not start, immediately turn the computer off to prevent the CPU and
other delicate components from overheating.
Basic Computer Skills
Welcome to a short, easy-to-master, web based course on basic computer skills. Our goal is to
give you a solid foundation. Once you have understood these basics, you will have a clear
understanding on which to build your future knowledge of and skill with computers.
To become acquainted with your computer there are certain basic skills to be mastered. While
these skills might seem obvious at first, the fact is that many people never take the time to learn
these very important basics. By studying them now, you will both save time later and also
improve your daily computer productivity.
Each section of this website contains a straightforward, self-paced introduction to these topics.
To access information about any topic, single click on that topic's name below.
Estimated time to complete this section: 55 minutes
Use a mouse to point, click and double-click
Keyboard and typing tips
Opening and closing software files
Accessing a CD-ROM
Locating a saved file
How to copy and paste files or text
Review Questions

10. COMPUTER BASICS
Seema Sirpal Delhi University Computer Centre
What is a Computer?
An electronic device that stores, retrieves, and processes data, and can be programmed with
instructions. A computer is composed of hardware and software, and can exist in a variety of
sizes and configurations.
Hardware & Software
The term hardware refers to the physical components of your computer such as the system unit,
mouse, keyboard, monitor etc.
The software is the instructions that makes the computer work. Software is held either on your
computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied)
from the disk into the computers RAM (Random Access Memory), as and when required
Mini and Mainframe Computers

11. Very powerful, used by large organisations such an banks to control the entire business
operation. Very expensive!
Personal Computers
Cheap and easy to use. Often used as stand-alone computers or in a network. May be connected
to large mainframe computers within big companies.
Hardware Components
Input Devices -" How to tell it what to do“
-A keyboard and mouse are the standard way to interact with the computer. Other devices
include joysticks and game pads used primarily for games.
Output Devices -"How it shows you what it is doing"
-The monitor (the screen) is how the computer sends information back to you. A printer is also
an output device.
Hardware Components
INPUT DEVICES
The Mouse
Used to ‘drive’Microsoft Windows
The Keyboard
The keyboard is still the commonest way of entering information into a computer
Tracker Balls

12. an alternative to the traditional mouse and often used by graphic designers
Hardware Components
INPUT DEVICES
Scanners
A scanner allows you to scan printed material and convert it into a file format that may be used
within the PC
Touch Pads
A device that lays on the desktop and responds to pressure
Light Pens
Used to allow users to point to areas on a screen
Joysticks

13. Many games require a joystick for the proper playing of the game
Hardware Components
OUTPUT DEVICES
VDU
The computer screen is used for outputting information in an understandable format
There are many different types of printers.
In large organizations laser printers are most commonly used due to the fact that they can print
very fast and give a very high quality output.
Hardware Components
OUTPUT DEVICES
Plotters
A plotter is an output device similar to a printer, but normally allows you to print larger images.
Speakers

14. Enhances the value of educational and presentation products.
Speech synthesisers
Gives you the ability to not only to display text on a monitor but also to read the text to you
Hardware Components
Storage Devices --"How it saves data and programs“
-Hard disk drives are an internal, higher capacity drive which also stores the operating system
which runs when you power on the computer.
-"Floppy" disk drives allow you to save work on small disks and take the data with you.
Hardware Components
Hardware Components
Memory

15. THE FIVE GENERATIONS OF COMPUTER
The Five Generations of Computers
The history of computer development is often referred to in reference to the different generations
of computing devices. Each generation of computer is characterized by a major technological
development that fundamentally changed the way computers operate, resulting in increasingly
smaller, cheaper, more powerful, more efficient and reliable devices.
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.
Vacuum Tubes

16. Prepared by Miss N. Nembhard 2
Magnetic Drum
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.
Transistors
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.
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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.

17. Integrated Circuits
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.
Microcircuits
Fifth Generation (Present and Beyond) Artificial Intelligence Fifth generation computing
devices, based on artificial intelligence, are still in development,
Prepared by Miss N. Nembhard 4

18. 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.
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History of Computers
1. 1623: Mechanical calculator
o Wilhelm Schickard invented first known mechanical calculator, capable of simple arithmetic.
o Similar mechanical adding machine made in 1640’s by Blaise Pascal. Still on display in Paris.
The "Pascaline," from The History of Computing Project
2. 1673: More advanced mechanical calculator
o 1673 by German mathematician Gottfried Leibniz o Capable of multiplication and division o
Purely mechanical with no source of power.
The "Step Reckoner," from maxmon.com
3. 1823: Charles Babbage begins work on Difference Engine
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o He designed, but it was completed by a Swedish inventor in 1854. o Image of the Difference
Engine from Niagara College
o Never completed. o Important concept: a general-purpose machine capable of performing
difference functions based on programming.
4. 1834: Ada Byron, Lady Lovelace impressed with the concept of the Analytical Engine at a
dinner party. o Daughter of poet Lord Byran o Created plans for how the machine could
calculate Bernoulli numbers. This is regarded as the first “computer program," and she is the first
"programmer." o The Department of Defense named a language “Ada” in her honor in 1979.
5. 1890: punched cards used by Herman Hollerith to automate Census
o Concept of programming the machine to perform different tasks with punched cards was from
Babbage. o Punch cards based on Josph Marie Jacquard’s device to automate weaving looms. o
Hollerith founded a company that became International Business Machines (IBM) to market the
technology.
Sample Punch Card, from About.com
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6. 1939: prototype of the first electronic computer
o Assembled by John Atansoff and Cliford Barry. o John Atansoff came up with the concept of
using binary numbers. o Completed in 1942 using 300 vacuum tubes. o Could solve small
systems of linear equations o Image from The History of Computing Project
7. 1946: ENIAC completed
o Electronic Numerical Integrator and Computer o By Presper Eckert and John Mauchly o
18,000 vacuum tubes. o Occupied a 30 by 50 foot room o Programming by plugging wires into
a patch panel. Very difficult to do, because this style programming requires intimate knowlege of
the computer.
ENIAC, from ftp.arl.mil

19. 8. 1946: John van Neumann Architecture stored-programming concept o He suggested that
programs and data could be represented in a similar way and stored in the same internal memory.
o All modern computers store programs in internal memory.
Prepared by Miss N. Nembhard 8
Summary - Generations of computers
1. Vacuum tube (1939) 2. Transistor (invented in 1947, used in IBM 7090 in 1958) 3.
Integrated circuit or chip (invented in 1959, used in IBM 360 in 1964) o A small wafer of silicon
that has been photographically imprinted to contain a large number of transistors together. 4.
Large-scale integration: microprocessor (1975) o Entire processing unit on a single chip of
silicon 5. Fifth Generation (Present and Beyond) Artificial intelligence some applications, such
as voice recognition, use of parallel processing and superconductors, The goal of fifthgeneration
computing is to develop devices that respond to natural language input and are capable of
learning and self-organization.
Vacuum tube, from computermuseum.li
Transistors, from Texas Instruments
Circuit, from IEEE Virtual Museum Old CPU's, from Wikipedia
Robert Noyce, one of the inventors of the integrated circuit and founder of Intel speaking of a
modern computer chip compared to the Eniac: "It is 20 times faster, has a larger memory, is
thousands of times more reliable, consumes the power of a light bulb rather than that of a
locomotive, occupies 1/30,000 the volume and costs 1/10,000 as much."
Source: Robers, Eric S. The Art and Science of C. Addison-Wesley Publishing Company.
Reading: 1995.

20. HARDWARE COMPONENTS OF COMPUTER
Notes - Computer Hardware Basics
The Computer A computer is made up of many parts:
1. Input/Output (I/O) devices – These allow you to send information to the computer or get
information from the computer
2. Central Processing Unit – CPU or Processor for short. The brain of a computer.
Approximately 1.5 in X 1.5 in. Does all the computation/work for the computer.
3. Memory – Although memory is technically any form of electronic storage, it is used most
often to identify fast, temporary forms of storage. Accessing the hard drive for information takes
time. When the information is kept in memory, the CPU can access it much more quickly.

21. a. Random Access Memory – RAM. Where information is stored temporarily when a program is
run. Information is automatically pulled into memory, we cannot control this. RAM is cleared
automatically when the computer is shutdown or rebooted. RAM is volatile (non-permanent).
b. Read Only Memory – ROM. More permanent than RAM. Data stored in these chips is
nonvolatile -- it is not lost when power is removed. Data stored in these chips is either
unchangeable or requires a special operation to change. The BIOS is stored in the CMOS,
readonly memory.
c. Hard Drive – Where you store information permanently most frequently. This is also
nonvolatile.

22. 4. Motherboard – A circuit board that allows the CPU to interact with other parts of the
computer.
5. Ports – Means of connecting peripheral devices to your computer. a. Serial Port – Often used
to connect a older mice, older external modems, older digital cameras, etc to the computer. The
serial port has been replaced by USB in most cases. 9-pin connector. Small and short, often
gray in color. Transmits data at 19 Kb/s.
b. Monitor Ports – Used to connect a monitor to the computer.
PCs usually use a VGA (Video Graphics Array) analog connector (also known as a D-Sub
connector) that has 15 pins in three rows. Typically blue in color.
Because a VGA (analog) connector does not support the use of digital monitors, the Digital
Video Interface (DVI) standard was developed.
LCD monitors work in a digital mode and support the DVI format. At one time, a digital signal
offered better image quality compared to analog technology. However, analog signal processing
technology has improved over the years and the difference in quality is now minimal.

23. c. Parallel Port – Most often used to connect a printer to the computer. 25-pin connector. Long
and skinny, often pink in color. Transmits data at 50-100 Kb/s.
d. USB Port – Universal Serial Bus. Now used to connect almost all peripheral devices to the
computer. USB 1.1 transmits data at 1.5 Mb/s at low speed, 12 Mb/s at full speed. USB 2.0
transmits data at 480 Mb/s.
e. Firewire/ IEEE 1394 Port – Often found on Apple Computers. Often used with digital
camcorders. Firewire transmits data at 400 Mb/s. Firewire 1394B (the new firewire) transmits
data at 3.2 Gb/s.
f. PS/2 Port - sometimes called a mouse port, was developed by IBM. It is used to connect a
computer mouse or keyboard. Most computers come with two PS/2 ports.

24. g. Ethernet Port – This port is used for networking and fast internet connections. Data moves
through them at speeds of either 10 megabits or 100 megabits or 1 gigabit (1,000 megabits)
depending on what speed the network card in the computer supports. Little monitor lights on
these devices flicker when in use.
6. Power Supply – Gives your computer power by converting alternating current (AC) supplied
by the wall connection to direct current (DC).
7. Expansion Cards – Used to add/improve functionality to the computer. a. Sound Card – Used
to input and output sound under program control. Sound cards provide better sound quality than
the built in sound control provided with most computers.
b. Graphics Card – Used to convert the logical representation of an image to a signal that can be
used as input for a monitor.
c. Network Card – Used to provide a computer connection over a network. Transmit data at
10/100/1000 Mb/s.

25. 8. CD ROM – A device used to read CD-ROMs. If capable of writing to the CD-ROM, then
they are usually referred to as a ‘burner’ or CD-RW.
9. DVD ROM – A device that is used to read DVDs/CDs. If capable of writing to the DVD, then
it is often referred to as a DVD-burner or a DVD-RW.
10. Floppy Drive – A device that is used to read/write to floppy diskettes.
11. Fan – Keeps your computer cool. If the inside of your computer becomes too hot, then the
computer can overheat and damage parts.
12. Heatsink – Used to disperse the heat that is produced inside the computer by the CPU and
other parts by increasing surface area.
13. The little parts – Capacitors – store energy, Resistors – allows a current through, Transistors
– a valve which allows currents to be turned on or off.
14. Case – (Tower if standing upright.) What your motherboard, CPU, etc is contained in.
The three main components of a computer: 1. CPU – Central Processing Unit, coordinates all
actions that occur in the system, executes program instructions. 2. Memory – Used to store
information. 3. I/O Devices – Input/Output devices, which allow you to obtain or display data.