Innovator of IT

1. Sir Tim Berners-Lee – World Wide Web
2. Vint Cerf And Bob Kahn – TCP/IP
3. Larry Page and Sergey Brin – Google Inc.
4. David Filo and Jerry Yang – Yahoo! Inc.
5. Bill Gates – Microsoft
6. Steven Paul Jobs – Apple Inc.
7. Mark Zuckerberg – Facebook
8. Chad Hurley and Steve Chen – YouTube
9. Linus Torvalds – Linux
10. Jack Dorsey – Twitter
11. Kevin Rose – Digg
12. Bram Cohen – BitTorrent
13. Mike Morhaime – Blizzard Entertainment
14. Jimmy Wales – Wikipedia
15. Jeff Preston Bezos – Amazon
16. Shawn Fanning – Napster, Rupture
17. Pierre Omidyar – eBay
18. Jack Ma – Alibaba
19. Craig Newmark – Craigslist
20. Matt Mullenweg – WordPress
21. Thomas Anderson – MySpace
22. Garrett Camp – StumbleUpon
23. Jon Postel – Internet Pioneer
24. Caterina Fake – Flickr
25. Marc Andreessen – Netscape

ASCII Code

ASCII is a character code electric transmission. ASCII stands for

American Standard Code for Information Interchange. American National Standards Institute (ANSI) developed this code. The first edition of the code was published in 1963.

Previously character was represented in different ways and it created problem to networking with other computer. Bob Bemer, an IBM engineer proposed ANSI to develop a single code for computer communication.

ASCII uses 7 bit for character code, that means 7 bit to represent each character. So, in total, 128 character can be represented by ASCII code.

If Gmail Is Hacked

You have your gmail account. You are trying to login and see the password is wrong ! Timid and disgusted, you quickly click "Can't access your account?" button, trying to reset password by your alternate email address. But no, hacker has already changed your alternate email address, your phone number, address, security question, everything ! What to do?

Don't worry.Only way to get back it, is to contact Google support center. Go to link below:

https://www.google.com/accounts/recovery

You will see a text, "having trouble signing in?". Select your field and submit to continue. Google will scrutinized your account info again, if everything is perfect then you will get back your account. It may take some days.

Why Babbage Is Called The Father Of Computer?

 

It isn't easy to select the boss of today's computer because there are tons of people who contributed in the field of computer science but Babbage is pioneer in that matter due to his invention and concept of the Analytical Engine.

Babbage, full name Charles Babbage, was a British mathematician.  In 1837 he came up with his concept for the first general mechanical computer,The Analytical Engine. It contained an Arithmetic Logic Unit (ALU), basic flow control, punch cards, and integrated memory. The design of this calculating machine strongly resembles the modern computer system and the overall organization is remarkably similar to the conceptual design of modern computers. Analytical Engine was intended to perform any arithmetical calculation using punched cards that would deliver the instructions, as well as a memory unit to store numbers. Ada Lovelace, another mathematician, who associated him by writing a program for the Analytical Engine.

Unfortunately, Babbage was not able to complete his project because of funding issues and thus his computer was never built during his lifetime. Babbage's son Henry Babbage constituted only a small part of the whole engine in 1910 which had some printing apparatus.

  

Though Babbage couldn't deliver the goods but he had that vision. Before Analytical Engine, he was involve in another project, the Difference Engine. The six-wheeled model was initially constructed and demonstrated to a number of audiences The difference engine was subsequently realized as actual working machines, so he was clearly on the right track. 

He is a pretty interesting person with some pretty interesting ideas, unfortunate in completing his project but no doubt, his idea was a leap in the field of computing. 

How to Convert from Binary to Decimal

Suppose a binary number 1100₂  and we will convert it into decimal form. The binary number has base 2. In the number (1100)₂ , 0 is the least significant digit and 1 is most significant digit. We will multiply each digit with the base 2 to the power index number. So binary number (1100)₂ has following index number of each digit- 

3 2 1 0 ---- index number or order of digit. It starts from 0
1 1 0 0 ---- the number

So, the multiplication will be like:

1100  =  1×2³  +  1×2²  +  0×2¹  +  0 × 2⁰  = 8 + 4 + 0 + 0 = 12 

So,  the decimal value of binary number (1100)₂ is  (12)₁₀

The fraction number can also be done in similar way but that time the power will be negative. Suppose the number (0.011)₂ .

0.011 = 0×2^-1  +  1×2^-2  +  1×2^-3    = 0 + .25 + .125  = 0.375 

So,  the decimal value of binary number (0.011)₂ is  (0.375)₁₀

Number Types

There are different types of number in mathematics. Different types of numbers have many different uses. We can also classified them as sets.

Natural Number:

The first type of number is 'natural' numbers. It is also called counting number. These are:

 1, 2, 3, 4, 5, 6, ... 40,41 ...100,101 ......
The set of natural numbers, denoted N, can be defined in N ={1,2,3,4}

Whole Number:

Same as Natural Number. Here it is together with zero:

    0, 1, 2, 3, 4, 5, 6, ...

So if we include 0 with natural number then it is whole number.

Integers:

Then come the "integers", which are set of zero, the natural numbers, and the negatives of the naturals. It is written without fractional part. These are:

    ..., –6, –5, –4, –3, –2, –1, 0, 1, 2, 3, 4, 5, 6, ... 

So +8 or -8 both are integer but 8.23 is not integer. 8.23 is a fraction. The set of integers, denoted Z, is formally defined as follows: Z = {..., -3, -2, -1, 0, 1, 2, 3, ...}

Rational numbers: 

The rational number is ratio of two integer numbers. So it can be written in the p/q form, where p and q are integers and q is not equal to zero. By dividing one integer by another integer may form a fraction.  For example, 5/2=2.5 but 4/2=2 does not make fraction.

So fractions are rational number but remember that fractions should be terminated (ending) or repeating decimals. Such as 1/2=0.5(fraction is terminated), 1.58/2= 0.79(fraction is terminated), or 4/3=1.333333.....(Here fraction is repeating). All these numbers are example of fraction. 

Irrational numbers:

Irrational means not Rational. Some numbers cannot be written as a ratio of two integers and they are called irrational number. For example:

√2=1.4142135623730950....... (fraction is non-terminating) 

π = 3.1415926535897932384626433832795 (and more...) 

Here fraction is endless. The decimal expansion of an irrational number continues without repeating.

Real numbers:
Real number includes all the number: natural,integer,rational and irrational numbers. It is denoted by R.

How to Convert from Decimal to Binary

The decimal number system has base 10 and binary number system has base 2. In study of computer science, we often need to convert a decimal number to a binary one. The following approach will teach how to convert a decimal number to a binary one.

The approach is simple. Take a decimal number 9 and now we will convert it to decimal.

Divide this number by 2 as it is the base of the binary numeral system. The remainder will always either be 0 or 1. Then keep this remainder and divide the quotient by 2. We will do this method until we reach the quotient as 0.

9 ÷ 2 = quotient 4 and remainder 1

4 ÷ 2 = quotient 2 and remainder 0

2 ÷ 2 = quotient 1 and remainder 0

1 ÷ 2 = quotient 0 and remainder 1  

Now start with the bottom remainder, read the sequence of remainders upwards to the top, we will get the binary number 1001. Here the last or bottom remainder is 1 as 1 ÷ 2 = quotient 0 and remainder 1 and top remainder is also 1 as 9 ÷ 2 = quotient 4 and remainder 1.

Take another decimal number 47 and its binary value is 101111. We will find it out now.

47 ÷ 2 =  quotient 23 and remainder  1

23 ÷ 2 =  quotient 11 and remainder  1 

11 ÷ 2 =  quotient 5 and remainder    1

5 ÷ 2  =  quotient 2 and remainder     1

2 ÷ 2  =  quotient 1 and remainder     0

1 ÷ 2 =   quotient 0 and remainder     1  

If start with the bottom remainder, read the sequence of remainders upwards to the top, we will get the binary number 101111.

Above we  have discussed about converting integer decimal into binary. What will we do in case of fractional number?  Suppose the number is .25 and how can we convert it into binary. We will do it in the following way:
First, we will multiply the fractional part by 2 and then keep the whole number part or the result. We will continue this approach until we reach to a full integer. So,
0.25  × 2 = 0.50  keep  0  (Here 0 is whole number part and .50 is fractional part)
0.50  × 2 = 1.0    keep  1  (Here 1 is whole number part and .0 is fractional part)
Now we will count it from top to bottom and we will get 01 as 0 is the top digit and 1 is the last digit.

So the binary of .25 is  0.01

Take another number  0.5625 and find its binary value.

0.5625  × 2 = 1.125  keep  1  (Here 1 is whole number part and .125 is fractional part)
0.125    × 2 = 0.25    keep  0
0.25      × 2 = 0.50    keep  0 
0.50      × 2 = 1.0      keep  1  

Start count from top to bottom  the binary number will be 0.1001

Binary Number

In numeral system, Binary Number System is simplest. The base or the radix of the binary system is 2. So, there are two digits: 0 and 1. Gottfried Wilhelm Leibniz, the co-inventor of Calculus, first talked about binary number in the paper 'Essay d'une nouvelle science des nombres' in 1701.

As there are two symbols: 0 and 1, so , all the numbers are represented with this two symbols. Below table shows how decimal numbers are represented in binary system -

Binary	0	1	10	11	100	101	110	111	1000	1001	1010
Decimal	0	1	2	3	4	5	6	7	8	9	10

Suppose a binary number 1010 that is equivalent to 10 in decimal. The rightmost bit is called  Least Significant Bit (LSB) and the leftmost bit is called Most Significant Bit (MSB). Then 1 is MSB and 0 is LSB.

Fractions can also be represented in binary system. Suppose decimal 22.75 can be written in binary as (10110.11). Arithmetic in binary is much like arithmetic in other numeral systems. Addition, subtraction, multiplication, and division can be performed on binary numerals. There is a method of converting binary number in other number system.

The binary system is used internally by almost all modern computers and computer-based devices. Each digit is referred to as a bit. Computer memory comprises small elements that may only be in two states - off/on - that are associated with digits 0 and 1. Such an element is said to represent one bit - binary digit. 

Binary arithmetic

Addition:
Addition is done exactly like adding decimal numbers. Below is just rule in binary addition like decimal system. When 1 is added with 1, the result will be 0 and there will be an extra bit 1 that is called Carry. This carry will have to be added in the next column.

0+0 = 0
1+0 = 1
0+1 = 1
1+1 = 0, and you carry a 1. 
The two binary numbers (110)₂=decimal 6 and (111)₂=decimal 7 can be add in the following manner. The answer will be (1101)₂ =decimal 13.
  110

+111
------------
 1101 

The above addition is for two positive numbers. But if it is the combination of positive and negative numbers then we have take other method. For example, when you handwrite a number that represent some physical quantity such as temperature, you can simply put a +  or - sign in front of the number to indicate that the number as positive or negative. Storing this value in computer is problematic.  To resolve this problem, it was decided that the most significant bit (MSB) will be reserved as sign data or bit.

To make computation easier with signed numbers, the magnitude of negative number is represented in a special form called 2's complement. It is formed by inverting each bit or digit and adding 1 to the result. Suppose in a 8 bit representation, the decimal number +5 can be written as 00000101 and decimal number -5 can be written as 10000101. Here we, at first, inverted 00000101(+5) and found 11111010. Then we add 1 with 11111010 and found 11111011(-5).  So addition of signed binary numbers can be done in following way -
0 0 0 0 1 1 0 1   (+13)
1 1 1 1 0 1 1 1   (-9) ( in 2's complement form )
----------------
0 0 0 0 0 1 0 0   (+4)

Subtraction:

Subtraction is same as decimal subtraction. When we subtract 1 from 0, the result will be 1 and we will hire 1 from next column. This hiring is called borrowing. Then the value of the next column becomes 0.

0 − 0 = 0
0 − 1 = 1, borrow 1
1 − 0 = 1
1 − 1 = 0
Here we subtract binary (1011)₂=decimal 11 from binary (10101)₂=decimal 21 and the result will be (1010)₂=decimal 10. In that subtraction method, larger number should be top and smaller number should be in bottom.  
 1 0 1 0 1
-  1 0 1 1
 ----------
    1 0 1 0

Multiplication:
Multiplication in binary follows same rule that we use in decimal.
0 x 0 = 0
1 x 0 = 0
0 x 1 = 0
1 x 1 = 1, no carry and no borrow

Here, we will multiply binary (110)₂=decimal 5 and (11)₂=decimal 3. The result will be (10010)₂=decimal 18.

          1 1 0
          x  1 1
     -------------
         1 1  0
      1 1 0
-- -------------

  1  0  0 1  0

What is Supercomputer?

 

A supercomputer is nothing but a big computer. Like our desktop or laptop computers, it has memory, processor, hard drive etc. but large in number. It consists of many processor and that's why it has high computational capacity.  Supercomputer is capable of processing enormous amount of data and it has high processing speed.

The history of super computer dates back to 1960. Seymour Cray, an American electrical engineer,  made the initiative to build a fastest computer at  Control Data Corporation (CDC) and in 1964, 'CDC 6600' was made. It was the flagship computer of supercomputer series by CDC.

Supercomputers are typically measured in FLOP (floating-point operations per second) instead of  MIPS(million instructions per second). Now a days, supercomputer performed at  some gigaflops or even in teraflops.

Basically the preferred supercomputer architecture today is called Parallel Computing, which means that we divide our problem up among a number of processors. Applications that use parallel processing are able to solve computational problems by simultaneously using multiple processors.

Supercomputers are very expensive and are employed for specialized scientific and engineering applications where it handles very large databases or do a great amount of computation. It is generally used in Quantum mechanics, Climate Research, Molecular Modeling, Simulation etc.

Numeral system

Numerals or numeral systems is the collection of notations or symbols to represent numbers. Like letters in a language which represent our speech graphically, numerals also represent number graphically. So A numeral is a symbol or name that stands for a number. For example 6, 70 and fourteen etc. All are numerals. 

 

Numeral systems are sometimes called number systems but they are not as same. A number is an abstract concept and a numeral is a way to express a number. A number two can be written in different numerals such as 2, II, or 10 (in binary system). What we write is a numeral, but most often we call them as numbers. That's why a confusion always remains over numeral and number.

There are different kinds of numeral system. It can be classified as positional or by base. Suppose Roman numerals, Indian numerals etc. are positional numeral system and binary, decimal are by base. Binary numeral has base 2 and decimal have base 10.

In real world, Decimal Numeral System is widely used. In every calculations at home, office, and in business, this numeral system is used. It has base 10(ten). Decimal numeral system includes a zero (0) and use symbols (1, 2, 3, 4, 5, 6, 7, 8, and 9)  to represent any number, no matter how large or how small. 

Binary numeral system has base 2 (two). It use 0 and 1 to represent any number. It is used in digital device (in computer and other electronic devices).

Below is example of Decimal and Binary numerals :

Decimal 0 -> Binary  0

Decimal 1 -> Binary  1

Decimal 2 -> Binary  10

Decimal 3 -> Binary  11

Decimal 4 -> Binary  100

Decimal 7 -> Binary  111

Decimal 20 -> Binary  10100

Hexadecimal numeral system has base 16. It uses sixteen distinct symbols. 0–9 to represent values zero to nine, and A, B, C, D, E, F  to represent values ten to fifteen. Hexadecimal numerals are widely used in computer system design.

Below is example of Decimal and Hexadecimal numerals :

Decimal 0  -> Hexadecimal  0

Decimal 1  -> Hexadecimal  1

Decimal 30 -> Hexadecimal  1E

Decimal 41 -> Hexadecimal  29

History of Computer(part-II)

In the part-1 of history of computer described about the earlier stage of the computer. The era of modern computer started from 1940. Development of electronic circuit replaced mechanical and elctromechanical devices.

The US-built ENIAC (Electronic Numerical Integrator and Computer) was the first electronic programmable computer built in the US(in 1946). It is regarded as the first general purpose electronic computer, the ENIAC was initially commissioned for the use in World War II, but not completed until one year after the war had ended. Installed at the University of Pennsylvania, its 40 separate eight-foot-high racks and 18,000 tubes were intended to help calculate ballistic trajectories. It contained nearly 18,000 vacuum tubes (nine times more than Colossus), was around 24 m (80 ft) long, and weighed almost 30 tons. ENIAC was built under direction of  John P. Eckert and John W. Mauchly.

Due to the development of Transistor, it slowly replaced vacuum tubes. The invention of transistor in 1947 giving rise to the "second generation" of computers. John Bardeen, Walter Brattain, and William Shockley   won the 1956 Nobel Prize in physics for this discovery. In 1951 the first computer for commercial use was introduced to the public; the Universal Automatic Computer (UNIVAC 1). Many new programming languages were invented at that time.

The next great advancement in computing came with the advent of the integrated circuit. Although transistors were a great advance on vacuum tubes but problem remained. Like other electronic components, it needed to be soldered together and Machines that used thousands of transistors still had to be hand wired to connect all these components together. That process was laborious, costly, and error prone. In 1958, Jack Kilby  at Texas Instruments successfully demonstrated implementation of ICs. He manufactured the first integrated circuit or chip. A chip is really a collection of tiny transistors which are connected together when the transistor is manufactured. Thus, the need for soldering together large numbers of transistors was practically nullified; now only connections were needed to other electronic components.

This discovery made the door open and that  led to the invention of the microprocessor and the world came to see third generation of computer. With this invention computers became smaller, more powerful more reliable and they are able to run many different programs at the same time. Before microprocessors were invented, computers needed a separate integrated-circuit chip for each one of their functions. (This was one reason the machines were still so large.) Microprocessors were the size of a thumbnail, and they could do things the integrated-circuit chips could not: They could run the computer’s programs, remember information and manage data all by themselves. The first microprocessor on the market was developed in 1971 by an engineer at Intel named Ted Hoff. Intel’s 4004 was the first microprocessor. A 1/16-by-1/8-inch chip called had the same computing power as the massive ENIAC.

A veritable explosion of personal computers occurred in the early 1970s. The first RISC architecture was begun by John Cocke in 1975, at the Thomas J. Watson Laboratories of IBM. Similar projects started at Berkeley and Stanford around this time. A company called Micro Instrumentation and Telemetry Systems (MITS) introduced a computer kit called the Altair.

Thousands of people bought the $400 kit. In 1975, MITS hired a pair of Harvard students named Paul G. Allen and Bill Gates to adapt the BASIC programming language for the Altair. The software made the computer easier to use, and it was a hit. Although the Altair spawned an entire business, two engineers in the Homebrew Computer Club in Silicon Valley named Steve Jobs and Stephen Wozniak built a homemade computer that would likewise change the world. The computer was called Apple 1.

The rest is history. Scientific invention and development made a new height of this device and each day it is advancing and changing the world. Today, laptops, smart phones and tablet computers allow us to have a PC with us wherever we go.

History of Computer (part-I)

The computer has long history that begun near about 2000 years ago. People have been using mechanical devices to aid calculation for thousands of years, for example, the abacus probably existed in Babylonia about 3000 B.C.E. The abacus was initially used for arithmetic tasks. In 1617 an Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. In 1641 the French mathematician and philosopher Blaise Pascal built a mechanical adding machine. It is considered as first mechanical calculator. He named it Pascaline. Gottfried Wilhelm Leibniz also came up with a machine for doing calculations. It could do much more than Pascaline. Leibniz has another important contribution to computing. He was the man who invented binary code, a way of representing any decimal number using only the two digits zero and one. In France(1801), Joseph Marie Jacquard invented a Power Loom that used wooden slat "punch cards" to make patterns on the loom.

Neither the abacus, nor the mechanical calculators constructed by Pascal and Leibniz really qualified as computers. In 19th century, English mathematician and professor name Charles Babbage designed the Analytical Engine which was the basic framework of the computers of today. This device, large as a house and powered by 6 steam engines. The analytical engine had expandable memory, an arithmetic unit, and logic processing capabilities able to interpret a programming language with loops and conditional branching. Babbage is also considered as 'Father of Computer'. Babbage was more fortunate in receiving help from Augusta Ada Byron, Countess of Lovelace, daughter of the poet Lord Byron. An enthusiastic mathematician, she helped to refine Babbage's ideas for making his machine programmable -- and this is why she is still, sometimes, referred to as the world's first computer programmer.American statistician Herman Hollerith built one of the world's first practical calculating machines, which he called a tabulator, to help compile census data in 1890. In 1936, Alan Turing wrote a mathematical paper called 'On computable numbers' and there he presented the notion of a universal machine, later called the Turing machine, capable of computing anything that is computable.  He proved that some such machine would be capable of performing any conceivable mathematical computation The central concept of the modern computer was based on his ideas.

What is Computer?

A computer is an electronic device that performed numerical calculations as well as logical operations. It is a general purpose device that can be programmed. Computer accepts information and manipulates it for some result based on a program or sequence of instructions on how the data is to be processed. Computer can not do anything without a Program.  Now a days computer can be used to type documents, send email, play games, and browse the Web. You can also use it to edit or create spreadsheets, presentations, and even videos. 
 

The word computer is made from the Latin word 'computare', this means machine for calculations. Charles Babbage is considered to be  'father of the computer'. He was the first person who designed mechanical computer that eventually led to more complex designs.

The basic components of a modern digital computer are: Input Device, Output Device, Central Processor Unit (CPU), mass storage device, and memory.

CC and BCC in email

 

CC means Carbon Copy. If you want to send same copy of your email to many person then you can use this field. You don't need to put all the email addresses in the 'To' field but the email address will be appeared to others as well. For example, if you CC roy@xyz.com and rob@xyz.com on an email, Roy will know that Rob also received the email, while Rob will know that Roy also received the email.

BCC means Blind Carbon Copy. This works as same as CC but the only difference is that other's email address will not be displayed to the recipients. So the recipient will not be aware of the fact that whom have got the same email. For example, if you BCC roy@xyz.com and rob@xyz.com on an email, Roy will not know that Rob also received the email, while Rob will not know that Roy also received the email. So the BCC list is secret – no one can see this list.

In case of reply, all the CC users will receive the reply email but in BCC only the original sender will receive the email.

The term comes form Carbon Paper. In old days, carbon papers were placed between two pieces of paper and while writing in top paper, the copy of writing was placed in second paper by the ink of carbon paper. As a result, a duplicate copy of document can be obtained. In CC or BCC a copy of original email is sent to others.
The To and CC fields work similarly but it is better to use CC in formal email.

PDF: What is PDF

PDF means Portable Document Format. It is a standard for document exchange. Adobe Systems is creator of this file format in 1993. Adobe cofounder John Warnock launched the paper-to-digital revolution with an idea he called The Camelot Project. Camelot’s goal was to give organizations the tools needed to "capture documents from any application, send electronic versions of these documents anywhere, and view and print these documents on any machines." PDF is used for representing documents in a manner independent of application software,  hardware, and operating systems. Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, and other information needed to display it. Adobe Systems invented PDF technology to smooth the process of moving text and graphics from publishers to printing-presses. PDF documents can be opened on any popular platform like Linux, Windows, Mac  and the  look will always be identical. PDF documents have a .pdf file extension. Now a days it is extensively used in magazine articles, product brochures, or flyers in which to preserve the original graphic appearance online.

You need PDF reader to read PDF file. There are many pdf reader available. Suppose Adobe Reader, PDF Reader, Nitro PDF Reader etc. and to create a PDF file you must need PDF writer like Adobe Acrobat Writer, PDF writer etc.

Initial release: June 15, 1993
Standard     ISO 32000-1
 

Alpha Channel

Alpha channel......
Few days ago, I wanted to put an image while generating PDF by using FPDF, I got an error that said 'Alpha channel is not supported'. I got stunned and started to think what is it?

In Computer Graphics , Alpha channel is used as an opacity channel. Alpha channel will ensure that how much your image will be transparent or not and it is an additional channel that can be added to an image which contains transparency information about the image. Depending on the type of alpha it can contain various levels of transparency. In PNG/TIFF alpha channel represents up to 256 levels of transparency.

A 32 bit graphics system contains four channels where three 8 bit channel are for Red,Green,Blue (RGB) and one8 bit alpha channel. So alpha channel is simply use of RGB model with extra information. Alpha channel values can be expressed as a percentage, integer, or real number between 0 and 1 like RGB parameters.If a pixel has a value of 0% in its alpha channel, it is fully transparent (and, thus, invisible), whereas a value of 100% in the alpha channel gives a fully opaque pixel .
The following are the file type that support alpha channel:
    * TIFF     * TGA     * PNG     * PSD (Photoshop)     * GIF (special alpha)