The Evolution of information technology Part-2

 How information was send at the first time?

At first , human were sent the information with the help of Home pigeon, Smoke etc. After some times human things how could they send information through electricity. But it was not easy to think about electricity , which sends information with two wires. They though about galvanometer because galvanometer can detect the electrical signal by deflection. A method was used to send information by using galvanometer but this method was very slow and costly as well. This method was send only 60 latter/min which was very slow. Then,  they thought about Permanent Magnet in the galvanometer. This method was known as TELEGRAM. The inventor of the telegram was Samul Morse.

Fig 2.1.1: Samuel Morse.

Samuel Morse was invented Morse code. Morse code was detected by DOT(.) and DASH(-). Two devices were used for Morse code.

Fig 2.1.2: Samuel Morse device.

It is used by tapping the combination of dots and dashes needed and pausing for the correct gap duration. There are longer gaps between words than letters in a word. The duration of gaps and the number of dots and dashes used determines what words or numbers the person is trying to convey via Morse Code.

Morse Device Working procedure:

Two devices were used -

Input Device: For one type, its detect dot(.). For three types, its detect dash(-).

Identical device: Two detect dot and dash , there is an identical device in another sides of the device.

Sending letter rate: 135 letter/min.

The sender must be skilled at the time of typing.

Fig 2.1.3: Morse code.

So information is converted-

Sound-symbol-Punch Card-Morse Code.

Idea of Measuring Information:

Likes other things information can be measured . In 1948,Claude E. Shannon , was given the idea of measuring information. He was said, Information is not a physical things, information can be measured. Claude E. Shannon is called the Einstein of Information technology. He was invented some rules to invented to measure information.

How can we measure Information?

Lets discuss an example , A toss of coin or use 6 letters to send information. 

Fig 2.1.4: coin toss.

When we toss a coin it can be head or tail. If we ask a question Yes or No. Is it Head Or is it Tail? What the answer is Yes or NO. So, one Yes or No question will decide the answer of the coin toss. So, one coin toss will carry one bit information. So , the unit of information is 1 bit. For 100 coin toss, it will carry 100 bits of information. 

For six letters how much information will it carry?

We know English language has 26 letter. We think the six letter as unknown like XXXXXX.

Lets take one letter as B. 

Fig 2.2.5: English Alphabet.

We first divide the whole Alphabet into two  categories like A-M and N-Z. Then question is B in that part?. If answer is Yes , we select the part. Then new part will divide into another two new parts. The again question B is in the part? If answer is Yes we select the part. It was seen that, if we question 4 or 5 times we will get our desire result. So, it can be called 4 or 5 bits. 

The equation for the measurement,

2^?=26

2=YES or No

?= Desired Yes or No result

26= total no of alphabet

The desired Yes or No value is-

?=4.7004

So, a 6 letter information will carry,

6*4.7=28.2 bit information.

So, a 6 letter information will carry more bits than 10 times coin toss.

Shannon limit:

Shannon gives the idea of how fast a information will send in one place to another place. This is called Shannon limit. In all over the world, all the information sent with Yes or No Question. Then Computer convert the Yes or NO as 0 or 1 binary code. Yes=1 and No=0.