The Linux operating system was developed by Linus Torvalds in the 1990s. The operating system is gaining some ground on the more well-known operating systems: Windows, Mac OS, and UNIX. These three popular operating systems have one thing in common: They generate great amounts of money for their developers. Linux, on the other hand, is available free of charge; its developer has not become a multimillionaire.

Why did Torvalds offer the code free of charge?

Perhaps so that people can just buy computers and use the Linux version of the system without the needs of having to pay for an expensive system, therefore having this system meets the standarts of cheap reliable new good stuff.

Why does he continue to do so today?

Im guessing there was probably a story behind him i did not read but the thing is that maybe he still does it because he realizes that why try now on becoming famous when their competitors allready are, and well you know it will be hard for them to get to the top considering the fact that linux is free it did not help him one bit, just got slowly to be known by people.

What is the philosophy behind his unique offering and how is it changing the world of software?

Maybe is changing it by people or owners having the chance to dwonload whatever they want onto linux, whether is mac or vista i think thats what i underdtand up to date with this version.