What are the main differences between BSD and Linux?

[hazel]

This is a question that's been bugging me for some time. I know that MacOS and Solaris are BSD variants, but what really is the difference between them and Linux (apart from the fact that they're proprietary of course, but I know that there are other BSDs that are free)? And how far are they compatible? For example, can you run Linux programs on BSD and vice versa or do you have to recompile them? There's a Wikipedia article comparing different BSDs but not one that compares BSD with Linux.

[GNU-Fan]

Linux is a kernel which knows how to talk to the hardware. The other software then does not have to care about the hardware and can just talk to the kernel, which is somewhat simpler and a lot more portable.

To have a useful operating system you need both a kernel and userspace programs.

So when someone builds a Linux distribution, he or she "goes shopping" on the Internet and throws in any software that looks useful. So "Linux" can mean a lot of things.
Linux and GNU - GNU Project - Free Software Foundation (FSF)


The BSD variants are different in that they develop and maintain a complete operating system. Minimal, but runnable. FreeBSD and NetBSD have a Linux compatibility layer that allows to run programs without recompiling -- to some extend.
But usually software is compiled for the specific target.

[techieMoe]

There's a pretty exhaustive article on this here:

BSD For Linux Users :: Intro

Just off the top of my head, the biggest difference is licensing. The BSDs for the most part use the BSD license rather than the GPL. The BSD license basically says you can do whatever you want with the source code, up to and including modifying it and putting those modifications into a commercial, closed-source project. Much of the Microsoft Windows network stack was "borrowed" this way.

Another difference is that the only thing that really distinguishes Linux is the kernel itself. Everything else is optional. The BSDs tend to treat every piece of software that they release as part of a single cohesive product. They test all the interactions between the programs they distribute against each other to make sure they work. This results in a particularly solid stability record.

[hazel]

There's a pretty exhaustive article on this here:

BSD For Linux Users :: Intro

Thanks, that's exactly what I wanted. What I especially like is that the author goes into the basic structural and philosophical differences and does so in a very fair and open-minded way.

[Ozzi]

Wow that is a great article. Cleared up a few things for me too.

Thanks TechieMoe