"Linux is famous for being 'open source' in that the source code
for Linux plus all the applications is normally available for those
who want to view or modify it.
"However, not all Linux programs are Open Source. Some are
'closed source' in that the developers who create it would like to
keep how they created it a 'secret'. The argument here is that the
company or developers have invested time and money in creating a
program, charge for their work so why should they go releasing the
code to any Tom Dick and Harry.
"Personally I have no issues with this, there are some good
programs for Linux which are closed source. One such program is the
flight simulator X-Plane. X-Plane is a paid for program and the 6
dvd set contains versions for Linux, Mac and Windows. It is in my
opinion the best flight sim available for the PC. In this article
I'll run through installing it on Ubuntu linux 9.10."