How does porting between Linux and Windows work?

Question

If a particular piece of software is made to be run on one platform and the programmer/company/whatever wants to port it to the other, what exactly is done? I mean, do they

Answer 1

Porting a piece of software that has not been made platform-independant upfront can be an enormous task. Often, the code is deeply ingrained with non-portable APIs, whether 3rd party or just OS libraries. If the 3rd party vendor does not provide the API for the platform you are porting on, you are pretty much forced into a full rewrite of that functionality, or finding another 3rd party that is portable. This only can be awfully costly.

Finally, porting software also means supporting it on another platform, which means hiring some specialists, and training support to answer more complex queries.

In the end, such a process can be very costly, for very little additional sales. Sadly, the decision is easy: concentrate on new functionality on your current platform that you know your customers are going to pay for.