Computers
History.
Binary digits.
Binary encoding.
Unicode.
Binary arithmetic.
Computer architecture.
Microprocessors.
Main memory or RAM.
Permanent storage devices.
Keyboard.
Touch screen.
Mouse.
Visual display unit.
Printer.
Microphone and speakers.
Other peripheral devices.
Hardware.
Software.
Machine level language.
High level language.
Operating system.
Application software.
Apps.
The ubiquitous computer.
Computer networks.
Internet.
History.
The computer is a fairly recent invention.
One of the first computers, came into operation, in 1945.
It was grandly called,
as the, Electronic Numeric Integrator and Computer,
or the ENIAC, in short.
The ENIAC could do 5000 additions, in a second.
It had an impressive memory capacity, of 80 bytes.
It was programmed, by manually resetting plugs and switches.
The ENIAC used 18 thousand vacuum tubes for computing.
The vacuum tube, was somewhat similar, to what was used in radios.
The ENIAC, was as big as a independent house.
It required, 200 kilo watts of power to run it.
It weighed 30 tons.
You can imagine that it was more of a monster, than a machine.
The ENIAC, was a sensation at that time.
It made headlines all around the world.
A new wonderful computing machine was born.
It was considered as, one of the most exciting discoveries,
of the 20th century.
The ENIAC, was one of the few, first generation computers, that was built.
Today a smart phone, has thousands of times ,the computing power, of the ENIAC.
In a short span of about 70 years, computers have transformed, our way of living,
and continues to transform, our life style.
An important invention, after the vacuum tube, was the transistor.
2nd generation computers, used transistors for computing,
instead of vacuum tubes.
This considerably reduced the size of the computer.
It also significantly increased the computing power, of 2nd generation computers.
The next invention, after the transistor, was the integrated circuit, or I C.
Integrated circuits, had many electronic components,
built into a single silicon wafer.
Computers using IC’s were called, 3rd generation computers.
These IC’s are also referred to, as chips.
They were used in the 1970’s.
The size of the computer was considerably reduced.
It used to be housed in a large air-conditioned room.
But the speeds of the 3rd generation computers, dramatically increased.
At this time, computers were used, by the government, defence,
and very large organisations.
They were also called, as mainframe computers.
In the 1950’s, no individual imagined, that he could own a computer.
The advent of the personal computer, changed all this.
Computers, became small enough, to keep on a desk top.
They worked much faster.
A typical PC had 256 kilobytes, of Radom Access Memory, or RAM.
It had a 880 kilobytes, 3.5 inch Floppy Disk Drive, for storage.
Importantly, it could do millions of calculations, per second.
They were affordable, even to an individual.
This marked the beginning of a new era.
Hundreds of millions, of personal computers,
have been produced and sold since then.
The use of Pc’s, as they were fondly called, became ubiquitous.
In 1982, the computer was named,
“Machine of the Year”. by Time magazine.
It replaced the conventional, “Man of the Year”, nomination.
Binary digits.
A binary digit is either 0 or 1.
That’s all.
This binary digit, is called as a bit.
So, a bit can be a 0, or a 1.
Computers understand only binary digits.
Computers are called digital computers, because of this.
Electronic circuits, can easily understand, two states, “OFF” or “ON”.
These two states, can be represented as 0 or 1.
Electronic circuits can work very, very fast.
So, it is of great advantage, if we can translate, anything that the computer has to do,
into binary digits.
This is what scientists actually did.
Binary encoding.
The languages that we use, has many characters.
For example,
The English language has 26 characters, from A, to Z.
We also use special characters like,
Plus, minus, comma, semi colon, etc.
All these characters, can be given a binary code,
comprising of a series of 0’s and 1’s.
For example, the character small j,
in binary code, is represented as,
1101010.
Similarly, all other characters can be encoded, in binary digits.
One common standard for encoding, is ASCII.
ASCII, stands for American Standard Code for Information Interchange.
The commonly used ASCII standard, uses 8 bits, to encode,
all the characters in the key board.
So, with 8 bits, we can represent all the English characters,
and all the special characters, we normally use.
These 8 bits together, is called as a byte.
So, 1 byte can represent 1 character, in binary code.
Thousand bytes is called a kilobyte, or KB in short.
Million bytes is called a Megabyte, or MB in short.
Billion bytes is called a Gigabyte, or GB in short.
Trillion bytes is called a Terabyte, or TB in short.
We will frequently come across, these terms, when discussing computers.
Binary encoding, makes it possible to work with characters,
in digital computers.
In digital computers, we store and manipulate, characters, in bytes.
When we say, a computer has 16 Gigabytes or 16 GB of main memory,
we mean, it can store 16 Billion characters, in memory.
When we say, a computer has 2 terabytes or 2 TB of disk storage,
we mean, it can store 2 Trillion characters, in the disk.
Unicode.
English is not the only language, that is used in computers.
The computers language, is basically binary.
We can convert, characters of any language, into binary.
So, computers can work with any language.
Scientists have already encoded the characters,
of all the languages in the world.
The standard used for this encoding, is called Unicode.
Thanks to Unicode, we can communicate to computers, in our mother tongue.
Binary arithmetic.
The numbers 0 to 9, can also be encoded in binary digits.
This kind of character encoding, is fine, for reading, storing and writing numbers.
For example, the number 3 2 1, can be stored in 3 bytes.
If we store a number as a character, it will be difficult to do arithmetic with it.
In roman numbers, I V, is four.
X I is eleven,
X V is fifteen, etc.
But roman numbers are not amenable to arithmetic.
In computers, a decimal number, is stored as a binary number.
The binary number, 1 0 represents the decimal number 2.
The binary number, 1 1 represents the decimal number 3.
The binary number, 1 0 0 represents the decimal number 4.
The binary number, 1 1 0 represents the decimal number 5.
This way any number, however large it is, can be converted to binary form.
The binary system, has great advantage, in electronic circuits.
We can design circuits, which can switch states, like OFF and ON,
which represents the binary digits, 0 and 1.
Like decimal numbers, binary numbers are amenable, to arithmetic calculations.
Binary arithmetic is very simple,
1 + 0 = 1.
1 + 1 = 1 plus 1 carry.
Using this rule, we can add 2 + 3, in binary.
1 0 + 1 1 is equal to 1 1 0,
which is five.
Multiplication is just a series of additions.
To multiply 2 into 3,
2, is added to itself 3 times.
Similar methods are used, for other mathematical functions.
By this methodology, we can use electronic circuits,
to do mathematical calculations.
All we have to do, is to convert our numbers into binary numbers,
and use binary arithmetic, to do calculations.
By using binary arithmetic, we can perform all the, mathematical calculations,
that we normally can do.
To multiply 100 by 50, we can add 100 to itself, 50 times.
At first sight, this looks like a tedious process.
But, it is worth it, simply because chips can perform,
Billions of such calculations, in one second.
This is something, that we cannot dream of doing.
So by using binary arithmetic, computers have become, millions of time faster,
compared to our own brains.
During the industrial revolution, machines leveraged our muscle capacity.
Machines can now perform, many tasks which is manually not feasible.
An equivalent phenomena, has now happened in the field of computing.
Computers can now perform calculations, at a speed,
which we cannot dream of doing, with our brain.
Computers have now become a leveraging tool,
to dramatically enhance the capacity of our brains.
Computer architecture.
We can identify two main components, of a computer.
The Hardware and the Software.
The hardware is all the electronic, and electro mechanical devices,
in the computer.
The software is the set of all the applications in the computer.
Applications is a set of instructions, which perform a certain type of functionality.
A word processing program, is an example of an application.
A typical computer, can have the following hardware components.
Microprocessor.
Main memory or RAM.
Permanent storage devices.
Keyboard.
Touch screen.
Mouse.
Visual display unit.
Printer.
Microphone and speakers.
Other peripheral devices.
The keyboard, Touch screen, mouse, and microphone are called as input devices.
The visual display unit, printer, and the speakers, are called output devices.
The input devices, the output devices, and the storage devices,
are together referred to as peripheral devices.
Microprocessor.
At the heart of the computer, is the microprocessor.
It is more like the brain of the computer.
The microprocessor, is a large scale integrated circuit.
It has the equivalent of millions of electronic components,
built into a single silicon wafer, of a size smaller, than a finger nail.
An electronic component could be a resistor, capacitor, transistor, etc.
Building all this functionality, involves incredibly complex and sophisticated technology.
Of course, it makes the microprocessor chip, minutely small.
We may wonder, whether building the functionality, of millions of components,
into a single wafer, is only to reduce the size.
Size is not the main reason, for building very large scale integrated circuits, or chips.
The smaller the chip, the faster is its operation.
This is because electricity, takes lesser time, to travel shorter distances.
Inside a microprocessor chip, the distance that, electricity travels,
is now measured in nanometers.
The speed of computing, has now become related to,
how many nanometers, electrical signals have to travel.
This speed, now measured in billions of operations, per second,
makes it worth while to miniaturise, very large scale integrated circuits.
The microprocessor performs, two basic functions.
Arithmetic function,
logical function.
Arithmetic function, are like addition, multiplication, etc.
These are simple arithmetic calculations.
The computer is not limited to only these, arithmetic calculations.
All mathematical functions, can be achieved by binary arithmetic,
inside the microprocessor.
But, the instructions to do so, must be supplied to it.
The basic logical functions, executed by the microprocessor,
is also very simple.
It performs basic combinations of ‘AND’ , ‘OR’, logic.
All instructions to the computer, has to be broken down,
to a series of, very simple instructions.
These instructions are called machine language instructions.
Instructions are also in binary form.
The microprocessor executes, only simple machine language instructions.
It applies the instructions, to the data supplied to it.
The great advantage of microprocessors are,
that, they can execute these instructions, at lightning speed.
Microprocessors today, can execute billions of instructions, in one second.
This gives it tremendous advantage, in terms of speed,
over the human brain.
The speed of a microprocessor is dependent on two factors.
One is the number of bits, that it can process, at a time.
For example, some microprocessors can process, 64 bits at a time.
They are referred to as 64 bit processors.
A 64 bit processor will be much faster, than a 32 bit processor.
The second factor, is a number of operations, that the processor,
can perform in one second.
When we say operations, we mean the most elementary,
of computer operations.
This operation could be, an elementary binary arithmetic operation,
or a logical operation.
A typical instruction that we write, in a computer program,
could be converted to hundred’s of machine level instructions.
The microprocessor, executes one machine level instruction, at a time.
A number of instructions, that it executes, in one second,
is another factor, which determines the speed of a computer.
Computers have a high speed clock.
The clock generates, high speed electronic impulses.
The speed of this clock typically correlates, to the speed of the microprocessor.
A 2.7 Giga hertz clock will generate, 2.7 billion impulses, per second.
These impulses are like drum beats.
With every impulse, one electronic operation can be executed.
The speed of the microprocessor, is often specified in giga hertz.
The technology of microprocessors, is rapidly evolving.
Newer microprocessors are much faster, than the older ones.
Microprocessors executes, billions of machine level instructions, per second.
The data, that is required for these instructions,
is also supplied to the microprocessor.
To hold the instructions, and the data that it is currently working on,
the microprocessor has a smaller amount of built in memory capacity.
This memory capacity is built into the microprocessor circuitry.
This high speed memory, in the microprocessor, is called cache memory.
Holding current instructions and data, in high speed cache memory,
increases the speed of the microprocessor.
The microprocessor in a sense, can be considered,
as the brain of the computer.
Main memory or RAM.
The instructions that the computer needs,
is stored in the main memory, or RAM.
RAM stands for Random Access Memory.
Some of the current data, that the computer is working on,
is also stored in the main memory.
If we open a document for example, it will be stored in main memory.
When it is closed, it will be stored, in a permanent storage device,
like the hard disk drive.
The main memory is only a temporary memory.
It needs power, to store contents, in the main memory.
When we switch off a computer, the contents in the RAM, is lost.
The main advantage of RAM, is that it provides, high speed access.
The microprocessor can easily, and speedily access,
the contents in main memory or RAM.
Having instructions and data, in RAM ,
significantly increases the speed of performance, of computers.
Instructions and data from the RAM, is sent to the microprocessor.
After executing the instructions, the results are sent back, to the RAM.
There is a constant interaction of instructions and data, between the RAM,
and the microprocessor.
The speed of RAM operations, will typically match,
the speed of the microprocessor.
The capacity of the main memory, or RAM is usually measured in Gigabytes or GB.
A computer with 16 GB of RAM, can hold 16 billion bytes, in memory or RAM.
The more the memory of the computer, the more instructions,
and data that it can hold in RAM.
Some sophisticated applications, like design software,
have a large number of instructions.
To hold such large applications in memory, we require larger RAM capacity.
Modern computers, usually have multiple applications open, at the same time.
For example, we might have a word processor, a spread sheet, a browser,
and a video player, open at the same time.
This enables us, to switch quickly between one application to another.
This is another reason, why it helps, to have more RAM, in a computer.
Permanent storage devices.
The software that we use in the computer, needs a place,
to be permanently stored.
Examples of application software, are:
Word processor software.
Spread sheet software.
Browser.
Video player, etc.
The computer has many such application software.
All these software is stored in permanent storage devices.
When it is required to be used, it is transferred to RAM.
All the data that we use, also is stored in permanent storage devices.
Permanent storage devices, are also called as mass storage devices.
Our documents, spreadsheets, music files, video files, etc., are data files.
Our data files are stored in permanent storage devices.
When required to be used, they are transferred to RAM.
When we open a document, a copy of the document, is transferred to RAM.
When we want to use, an application software,
a copy of the application software, is transferred to RAM.
Some of the commonly used permanent storage devices are:
Hard disk drive.
Solid state drive.
DVD drive.
Blue ray drive.
Flash drive.
Hard disk drive.
The hard disk drive, has a rotating magnetic disk.
It is made of Ferro magnetic material.
It is driven by a motor.
The disk has many tracks.
Tiny spots on the disks can be magnetised.
These tiny spots, can be in an “OFF” or “ON” state.
These “OFF” or “ON” states, can be used to represent,
the binary digits, 0 or 1.
This way all binary instructions and data, can be stored,
in a magnetic disk.
When the disk rotates, a read write head,
reads the data, from the magnetic disk,
or write the data, to the magnetic disk.
The software and data, in the magnetic disk, is permanently stored.
When we switch off the computer, it is not erased.
We can store large amounts of software, and data in hard disk drives.
The access to this software and data, is reasonably fast.
But, it is not as fast as access to RAM data.
That is why, it takes a little while, to transfer a large application,
like a spread sheet, from hard disk to RAM.
This is also the reason, that we transfer software and data,
that we currently use to RAM.
Hard disk drives, have much more capacity, then RAM.
The capacity of hard disk drives, is measured in Gigabytes or GB.
A 500 Gigabytes or GB, can hold 500 billion bytes of data.
The magnetic disk, of a hard disk drive, cannot be removed.
This contrasts some other type of drives, like DVD drives,
where we can remove, and carry the disk.
So, we normally will keep all the software, and permanent files, in the hard disk.
Solid state drive.
A hard disk drive, is a electro magnetic device.
The same functionality, of permanent storage can be achieved,
by using solid state drives.
Solid state drives, use only electronic circuits, for storage.
There are no moving parts.
They are typically faster, than hard disk drives.
They can also hold much more data.
In future, we can expect, a more wide spread use, of these devices.
The capacity of solid state devices, is measured in Terabyte.
A 2 Terabyte solid state drive, can hold two trillion bytes of data.
DVD drive.
DVD drives are digital optical disk storage devices.
They use light signals from a Laser beam, to read, write and store, digital information.
DVD was originally called, as Digital video disks.
It is more appropriate now to call them as Digital versatile disks.
A DVD disk can store, all kinds of digital information.
It can store data, software, images, audio files, and video files.
Compared to hard disk drives, DVD drives are much faster.
The transfer rate of early models, were about 1.4 Mega byte per second.
Currently, the speeds are about 24 times faster.
They are referred to as 24 cross.
These models can transfer more than 30 MB per second.
A DVD disk can typically store more than 8 GB of information.
The DVD drive is a removable storage device.
We can remove the DVD disk and store or transport it.
This we cannot do in a hard disk drive.
This is one of the advantages of using a DVD drive.
Software vendors, often offer their software in DVD disks.
For example, we can buy office management software, in an DVD disks.
Video files like movies, can also be stored in DVD disks.
Movie producers, sell their movies, in DVD disks.
Computer games, is software, which is also sold in DVD disks.
We can have a library of DVD disks, which has encyclopaedias,
music, games, movies etc.
We can use the disks, as and when we require it.
A more recent version, of the DVD disk,
is called the Blue ray disk.
It uses a Blue Laser beam, to read and write data.
It is faster, and has a higher capacity.
Flash drive.
Flash drives use flash memory, or EE PROMS, for storage.
E, E, P, R, O, M, stands for,
Electrically, erasable, programmable, reed, only, memory.
They are fully electronic, and a very convenient way,
to store, reed and write data.
It is also very convenient to carry and transport.
These drives are widely used in many electronic equipment.
The memory card used in smart phones, is one example.
The storage in an MP3 player is another example.
Data files can also be stored, and transported, with a flash drive.
Flash drives connect to the computer, via, a USB port.
U, S ,B, stands for Universal Serial Bus.
USB is a standard way, to connect peripheral devices, to the computer.
A typical flash drive, might have, a capacity of 16 GB.
Keyboard.
The keyboard is an input device.
We communicate, with the computer using the keyboard.
The keyboard has one key, for the normally used characters.
The layout of the keyboard, mimics that of a typewriter.
This is for historical reasons.
Earlier people were used to typewriters.
The keyboard was designed, to make a smooth transition,
from the typewriter to the computer.
Both data and instructions, can be keyed in, using a keyboard.
A keyboard can have a wired connection, to the computer,
to send a unique signal, for each key that is pressed.
The keyboard can also, have a wireless connection, to the computer.
The wireless connection is established, using blue tooth communication.
Touch screen.
A touch screen is a touch sensitive device.
It is a input device.
The screen displays, the keys that we can touch.
When we touch a key, a unique signal is sent to the microprocessor.
Touch screens are widely used in tablet computers, and smart phones.
In future, we can expect many more devices to have a touch screen interface.
Mouse.
The mouse is a input device.
A mouse can be used to pin point, a particular place, on the screen.
For example, the screen can display, many menu options.
The mouse can be moved, to point the cursor, at an option, in the screen.
By clicking the mouse, we can choose the option.
The mouse has become, a convenient way to interact with the computer.
Visual display unit.
The visual display unit, is an output device.
It is called as a display, in short.
It is the device by which, the computer communicates, with us.
The display can be, texts, images, or videos.
This is displayed on the screen, which we can read or see.
The display unit, typically has a LCD screen.
L,C,D stands for Liquid Crystal Display.
Liquid Crystal technology manipulates light, the way we want it.
A LCD display has many small points, called pixels.
Pixel is the short form of the term, picture element.
All the pixels together, display the image.
For a given LCD screen, the more the pixels that can be displayed,
the more the resolution, of the screen.
Higher resolution screens, can display sharper images.
For example, a LCD screen with a 1920 cross 1080 resolution,
displays 1920 pixels, in the length, of the screen.
and 1080 pixels in the height, of the screen.
The display, in this case, displays approximately 2 million pixels.
Even higher resolutions, are now available.
Each pixel, in the display, has an attribute, like colour.
Though there are only, 3 basic colours,
the actual colours, that we can see, is many millions of combination of these colours.
These are shades of the colour, like light blue, sky blue, peacock blue, dark blue, etc.
To represent these shades, a binary code can be used.
If we have more bits, in the binary code, we can represent, more shades of colours.
If we have a 32 bit colour display, we can display millions of shades, in each pixel.
Printer.
The output of the computer, can be printed, using a printer.
The printer uses, standard paper sizes.
We can print, text and graphics, with the printer.
If we use a Braille printer, the output can be in Braille format.
Printers now have additional capabilities.
They have become multipurpose devices.
They can be used to make copies of a document.
They can also be used to scan a document,
and take the image file, into the computer.
The printer can be connected, to the computer, via a cable.
It can also be connected, wirelessly, to the computer.
Microphone and speakers.
Another way, to interact with computers,
is through audio signals.
We can input voice, through a microphone.
We can hear the output, through speakers.
The microphone, acts as a input device.
The speakers, act as an output device.
The microphone and speakers, can be external, to the computer.
They can also be built into the computer.
The technology of voice input, is now available for computers, even smart phones.
We can give voice commands, to computers and smart phones.
Voice recognition software, is used for this purpose.
If we dictate notes, into the computer, it can convert the audio input into characters,
and store it as a character document.
The contents of the display, in the computer, can also be read out.
This is done using, speech synthesis software.
Other peripheral devices.
Many types of devices, can be connected, to the computer.
For example, a camera can be connected, to the computer.
Many other devices are now, connected directly to the computer.
This trend will continue to expand, the type of devices,
that a computer can interact with.
Computer in robots, control mechanical movements.
The Mars rover, is moving around in the planet Mars,
many millions of kilometres away.
The Mars rover has many type of scientific instruments, attached to it.
All these are controlled by people, on Earth, with computers.
Hardware.
The microprocessor, the RAM, the keyboard, the mouse, the display,
the printer, the storage devices, the microphones, the speakers,
and all the peripherals are collectively, referred to as the hardware,
of the computer.
We mentioned, that the microprocessor, is like the brain of the computer.
We should actually consider it, as the empty brain.
Without instructions, the computer, is not capable, of doing anything.
The instructions to the computer, is collectively referred to as the software.
Software.
If we consider computers as intelligent machines,
the credit, should go to software.
Computers execute, very basic instructions.
The language of this basic instructions, is called as, Machine Level Language.
A set of instructions, is called as a program.
A program achieves a specific objective.
For example, we can have a word processing program.
This is also referred to, as an application software.
In practice, programmers or software professionals,
develop programs, in high level languages.
These high level languages, are easily readable and understandable.
These high level language programs, are converted to machine level language.
We can have different application software, to achieve different objectives.
For example, we can have application software, for:
Browsing.
email.
Social networking.
Spreadsheets.
Music player.
Video player, etc.
We can have any number of such application software,
stored in the computer.
We can use a particular application software,
as and when it is required.
Programmers are software professionals.
They develop application software.
All the application programs, is collectively known as the software,
of the computer.
The computer is as intelligent, as it’s software.
Today computers can beat a grandmaster, in chess.
This is because, the chess software has become more and more sophisticated.
Software is developed, by software professionals.
Can a software professional develop software, to beat a chess grandmaster?
Normally no.
They would need the help of chess champions, to design the software.
Typically, the software professional,
only translates the knowledge, of the functional specialist,
into an application software.
In this way, knowledge is transferred, from a specialist, to a computer.
A space scientist, for example, can transfer his knowledge,
of controlling a satellite, to the computer,
with the support of the software professionals.
Knowledge in many fields, has already been programmed, as application software.
These are capable of enhancing our performance, in any profession.
Machine level language.
Instructions to the computer, are executed by the microprocessor.
The microprocessor, can execute, a very limited number,
of machine level instructions.
The most basic instructions, are called operation codes.
A typical machine level instruction, will comprise of, an operation code,
and a memory address.
This instruction will be in binary format.
Ultimately this is what the microprocessor executes.
It is called Machine Level Language.
High level language.
It would be very tedious, to develop software in machine level language.
In practice, software is developed, in high level languages.
High level languages, are easy to read and understand.
Java, C++, FORTAN, PERL, Pascal, Ada, are examples of high level languages.
There are many, high level languages.
A computer cannot understand, or execute,
a high level language instruction.
Software written in high level languages, are translated into,
machine level language.
This by itself would have been, a tedious process.
But, thankfully, this process has been automated.
Software, known as compilers, automates the translation process.
So, software professional never gets to see, the machine level language program.
The computer only knows and executes, machine level programs.
In this manner, we are able to communicate, easily with the computer.
Higher level languages, are becoming more and more sophisticated.
Many of them, or also becoming very user friendly.
It is possible, for a non software professional, to communicate with the computer,
by writing instructions, in a user friendly high level language.
For example, a spreadsheet software, allows us to use,
simple, understandable instructions.
We can develop a fairly sophisticated application, using a spreadsheet software,
without knowing a special programming language.
In future, we are likely to have more user friendly, programming languages.
Some schools, have already started teaching, primary school children,
to program, using such languages.
Operating system.
The operating system, is a software.
It is called O S in short.
It co-ordinates and controls, all the components of the computer.
The microprocessor, the RAM, the permanent storage devices,
the input devices, the output devices, and all other peripheral devices,
is some kind of super manager, of the computer.
The operating system or the O S,
acts as the interface, between the application software, and the computer.
So, the O S not only manages, the hardware, it also manages the software.
This helps in integrating, all the functions of a computer,
into a smoothly functioning, user friendly machine.
Some examples of operating systems are,
Windows, OS ‘X’, Unix, Linux, Android, etc.
We can drive a car, without knowing the technology,
of how internally the mechanisms, of the car works.
A similar thing, has happened in computers.
We can use computers, without worrying about it’s internal mechanisms.
Application software.
An application software, is developed to address, a specific need.
Organisations, develop these software, and sell it to users.
Some application software, is available free of cost.
We will discuss some examples, of application software.
Email software.
This software helps to send an electronic mail, to another person.
An organisation, or an individual can register, a unique email address.
Email software, provides a functionality of transferring the mail,
from one person to the other person.
Typically emails, have simple text content.
We can attach files, to an email.
The attachment can be a document, a spreadsheet, an image,
an audio file, a video file, etc.
With email, any one can communicate with any one else, in the world.
Smart phones, can send and receive emails.
Browser.
Browsing software, helps us to navigate, the internet.
We can reach any website, using the browser.
Browsing software, is available on a smart phone.
Word-processing software.
This software, helps us to create and edit documents.
It provides many features, for formatting the documents.
For example, we can choose the font, font size, colour, etc.
We can highlight, underline, sentences.
We can include images, inside the document.
We can also include audio and video files.
Spreadsheet software.
Spreadsheet software, is very useful to work with numbers.
We can do, all the arithmetic operations, using spreadsheet software.
Many advanced functions, are built into spreadsheet software.
For example, if we want to calculate, the compound interest,
a built in function, is available to do this.
Hundreds of such readymade functions, are available, in spreadsheet software.
We can also write our own custom function, with easy to use commands.
This makes spreadsheet software, a very powerful and versatile software.
Search engine software.
The internet has wealth of information.
There is so much information available, we need a special tool,
to search for the specific information, that we want.
Search engine software, is the tool that provides this function.
By entering some key words, we can home in, on the specific information,
that we need.
Search engine software, has become a ubiquitous tool, to find information.
Audio player software.
Audio files, are encoded in a special format.
One such commonly used format, is the MP3 format.
The audio software reads the audio file, which we can hear through the speakers.
The music players, which reed audio music files, are very popular.
Most of the popular music in the world, is available as MP3 files.
We can download this, from the internet, and listen to it.
Audio books, are also available.
These audio books could be knowledge books, or even story books.
Screen reader software.
Screen reader software, reads the text available on the screen.
This is very convenient for visually impaired persons.
Very sophisticated screen reader software, are now available.
We can also navigate the internet, and reed what we want.
Video player software.
Movie or video files, are encoded with a special format.
Video player software, reads these files,
and displays the video, on the screen.
Computer aided design software.
Engineers design equipment and machinery.
Computer aided design software, or Cad software helps to do this.
Mechanical engineers use design software, to design components and machinery.
Electronic engineers use design software, to design circuits.
Architects use design software, to design buildings.
Many other such design software, is available, for different professions.
Social networking software.
This software helps, people to communicate with each other.
Family, friends, and interest groups, usually network, using social networking software.
It is used for both formal and informal communication.
This software allows to share, texts, images, and videos.
This way of social communication, is increasing day by day.
This platform can also be used for promoting, socially relevant causes.
This trend is also increasing.
Apps.
We have discussed a few examples, of application software.
Thousands of other application software, is now available.
Software is now available for almost any field, we can think of.
Many of this application software, can be used in smart phones.
They are called Apps in short.
Thousands of Apps have been developed, and are available free of cost,
or at an affordable price.
We can download these software, into our smart phones.
For example, we can download software,
that can play chess, as good as a grand master.
If we get tired, of this chess app, winning all the time,
we can set the skill level, of the app, to low,
and have the satisfaction, of beating the software, a few times.
Apps are available for, finger print recognition, voice recognition, face recognition,
exercise measurement, maps, GPS, language translation, and so on, and so on.
Many scientific and educational apps, are also available.
We can learn what we want, when we want to.
The ubiquitous computer.
When the ENIAC was built in 1945, there was absolutely no problem,
in identifying it as a computer.
Like we discussed, it is more of a monster than a machine.
Computer technology, has very rapidly evolved, since then.
Today we have super computers, main frame computers, personnel computers,
laptops, notebooks, tablets, smart phones, etc.
We have computers, to suit every need.
Intelligent devices.
The microprocessor is not only used in computers,
it is also used in many other devices.
Most machines and equipment, incorporate microprocessors.
Sensors are used to sense, physical parameters like,
temperature, light, sound, pressure, etc.
Sensors can also be used to sense chemicals, and bio-chemicals.
These sensors, can be interfaced with microprocessors.
This becomes a powerful combination.
A combination of sensors, and microprocessors, makes a device intelligent.
A thermostat senses the temperature, and continuously regulates the temperature,
inside a building.
Modern factories have microprocessors, incorporated with most of their equipment.
A petroleum refinery, is typically controlled, by process control equipment,
which has many microprocessors.
Similarly, most industries incorporate microprocessors, in their equipment.
In hospitals, microprocessors are used in most equipments,
for example, in electrocardiograph machines, in CT scanners,
even in blood testing equipments.
Microprocessors, are present, in most of the day to day devices, that we use.
A TV remote, for example, uses a microprocessor.
It enables us to intelligently interact, with the television.
It is present, in clocks, in water heaters, in ovens, in television sets, in refrigerators,
in washing machines, in cars, in traffic signals, in cameras, toys, etc.
In a broader sense, all intelligent devices, can be considered, as having computers.
From this perspective, computers have pervaded, all facets of our life.
It is difficult to imagine, life on Earth, without computers.
In the planet mars, there is a rover, which uses computers.
In summary, we can say, that computers, have become a ubiquitous device.
Computer networks.
Computers can be connected, to one and another.
In this manner, computers can communicate, with other computers.
A system of inter connected computers, is called as a computer network.
The power to communicate with each other, dramatically increases,
the power and capabilities of computer networks.
The size of a computer network, can vary widely.
We can have very small networks, with a few computers,
to very large networks , with thousands of computers.
In the broader sense, we can include intelligent devices, in the network.
A home computer network, can connect all the computers,
and all the intelligent devices, used at home.
A smart home as it is called, can control power consumption, home security,
air conditioners, fire alarms, TV, refrigerators, ovens,
the house keys and the car keys, can all be networked.
Of course, we can continue to use computers, for our normal work also.
It is possible, that with a device, like a smart phone, we can manage,
all the devices, in our home.
A school can have, all its computers connected, in a school network.
All the students can be networked, with all the teachers.
A digital library, in the laboratories, can be part of the network.
A small office, can network all its computers.
All the staff, can work in a collaborative way, from their own desk.
Work done by one person, can be made available for other staff members.
They can also share, a common database.
These small and medium sized networks, are also called as,
Local Area Networks, or LAN, in short.
A petroleum refinery, has process control equipment, to manage,
all the machinery in the refinery.
This is interfaced, with computers, in a control room.
By working from the control room, engineers can manage, the whole refinery.
A global bank, can also have a computer network.
In this case, all the offices, around the world, will be networked.
Though the offices, might be thousands of kilometres apart,
all the employees, all over the world, can work together.
ATM’s are intelligent devices.
All the ATM’s of the bank, can also be part, of the bank’s network.
Such large networks are also called,
as Wide Area Networks, or WAN in short.
One computer network, can also connect , to other computer networks.
For Example, the networks of all the banks, can connect to each other.
In this way, we can transfer funds, from anywhere, any bank,
to any other person, any bank.
This kind of networking technology, is already in use.
Internet.
The internet is a global system, of interconnected computer networks.
Each node in the network, has a unique address.
This address is called, as the internet protocol, or IP address.
Each IP address, can uniquely identify, one node, in the internet.
Currently, we use a 32 bit identifier, for each IP address.
Billions of such IP addresses, are now available.
An organisation, can own one or more, unique IP addresses.
An individual can also own, an IP address.
The computer can host, relevant information about the organisation, in it’s data base.
Usually, this information is stored as Web pages.
An IP address can be represented, as a set of four numbers, separated by a full stop.
Example, 74.125.236.78.
Is a unique IP Address.
It is more convenient, to have a name as an address.
In practice this is what we actually do.
The company Google, has a unique name, called google.com.
This translates, to an unique IP address,
74.125.236.78.
The translation is automatic.
Routers, in the network, help to locate, an IP address.
Communication messages, are packaged, in convenient packets.
Packets are routed from source to destination,
by a series of routers.
Other organisations also have a unique name.
Example, Wikipedia.com.
faculties.com.
These are commonly called as websites.
Most organisations have a website.
Many more are getting to be on the internet.
A website, usually stores information, as web pages.
We can navigate, from one page to another.
Using links, we can directly go, from one page to another relevant page.
This link is called a hyper link.
For example, in the faculties web site,
there are options for Physics, Chemistry, Biology, and Environment.
Clicking on Physics, directly takes us to a page,
with all the Physics topics.
One of the topics, is computers.
Clicking on computers, takes us to the relevant module, on computers.
All the web sites, are collectively, called as the World Wide Web,
or WWW in short.
We use software, to navigate, the World Wide Web.
This software is called, as an Internet browser, or just a browser.
Thanks to the internet, we can retrieve most of the information, that we need.
Civilisation is set to have gone through 3 major technological revolutions.
The first was the agricultural revolution.
The second was the industrial revolution.
We are in the middle , of a exciting third revolution,
the information revolution.
The information revolution, is playing a big role,
in spreading knowledge, to all the people, with internet access.
Today, a smart phone, can access the Internet.
This makes access to the internet, even more affordable.
Any one with a smart phone, can access any information, on the internet.