SmartOS is based on Illumos, which is a fork of the short lived OpenSolaris distribution from Sun. OpenSolaris was based on Solaris, which was based on SunOS, which was a combination of BSD and SVR4. In other words, this is real Unix, modernized, battle tested, and focused. On my drive to work this morning I was thinking about all the different platforms that a Linux kernel needs to be aware of. Of course, not every device runs the exact same kernel, but the kernel still needs to be able to run on big iron servers, workstations, desktops, laptops, tablets, cell phones, wifi routers, and probably toasters too. Linux has a big job, and a lot of responsibilities. SmartOS, by comparison, has only one.