difference between Linux kernel and UNIX kernel(such as FreeBSD) from programmer's point of view

Question

difference between Linux kernel and UNIX kernel(such as FreeBSD) from programmer\'s point of view. I searched several articles about this. They compared these from User\'s v

Answer 1

From a standards point of view there really isn't any difference. Linux is a "POSIX" compliant OS, FreeBSD, Mac OS X and Solaris are also all "POSIX" compliant. In theory at least.

Once you move past the standards there are quite a few differences. Linux as inotify, udev and a bunch of other systems that are unique to it. FreeBSD has kqueue. There are differences in their exact implementations of things like ptrace. For example Mac OS X's ptrace has almost no functionality that you will find in the other Unix systems.

Beyond custom libraries there are differences in development tools. Solaris and FreeBSD have dtrace. Linux has valgrind. Mac OSX has instruments.

What level you are looking at will affect what differences you see or don't see.