why the keys in keyboard are arranged like a s d f .....?why its not like a b c d ?

Answer 1

It was because of the first major re-release of an early typewriter. The older system used to jam up with them arranged alphabetically. He found when he re ordered them it made HIS type writing machine more efficient, and then he released it in a hurry. Later there came a different keyboard that was more efficient, but not by much. Since it already had been widely produced and accepted and there was very little in means of difference of speed even with a "good" arrangement of letters it was already too late and people had become accustomed to the current arrangement. Just goes to show you how quickly people can become stuck in our ways...

Big fluke, because of a quick business decision.

Answer 2

The concept is that the letters you use most in english will be linked to your dominant fingers.