Pretty much everything that isn't windows (including mac os x) is ultimately derived from Unix, which was created by Bell Labs (part of AT&T) in the 70s. A diagram such as that here shows just how complicated things became.
Therefore it's fair to say all software, as windows run natively on macs is as fast as equivelent windows PCs.
For other operating systems (not windows or unix based), there was BeOS which was killed by MS (eventually MS lost the court case but too late). Some people are trying to remake the OS.
There's also IBMs OS/2, the technology from which was made into windows NT then 2000 and XP when MS cancled their partnership with IBM. IBM still make OS/2.
Note that the different unix OSes have their own kernel (all linuxes have the same kernel base (often customised), and BSD, Solaris, HP-Uxand Mac OS has its own. Though much of the components are shared.