Who is a cracker and who is hacker?  

I would have to say that a cracker, cracks into things to steal things that are of value to them. A hacker, hacks into things to destroy something that belongs to someone else.

A cracker cracks into things to obtain certain info. A hacker exploits a computer or server for some purpose. It depends, it could go both ways, they could be helpful by helping us find exploits and repair them, or they could be malicious and destroy and steal info.

'Hacking' is basically 'putting networks together to make them work for you.'

'Cracking' is basically 'breaking into a network to get something out of it.'

They both share a lot of the same skills, but end differently - like a Batman-style vigilante (the hacker) and a dirty cop (the cracker) ... the second one worked his way into the system for selfish reasons, & the first uses different systems to make the system better!

In essence, hackers and crackers have the same knowledge and skills. The majoe difference lies in the intention.

The term 'hacker' came first. It was used for programmers who try to disect computer programs, whether as a whole or any subroutine. The purpose is to see how the program works, and to find out any weaknesses. The next step is to figure out ways in which the program can be improved, and to analyse what could happen if the weaknesses are not rectified.

A cracker would try to find ways in which the weaknesses can be exploited to his or her profit. A comparison is between a locksmith and a burglar. Both can pick locks, but with different motives.