I wonder how close NetBSD’s design is to 4.4BSD, the last version of BSD from UC Berkeley’s CSRG? My understanding is that FreeBSD has a lot of features that are exclusive to it, such as jails and Capsicum, and FreeBSD also has some Solaris-derived components such as ZFS and Dtrace. I’m under the impression that NetBSD’s specialty is in providing a BSD that is easily portable to a wide range of architectures. Because BSD is not just a kernel, but an entire operating system, NetBSD’s portability makes it attractive when choosing a Unix for “exotic“ hardware.
the bsd kernel is made by the same team as the rest of the system, and follows the same release schedule. Thus they can add a new syscall (e.g., pledge in openbd), and update all the programs at once to use it. That wouldn't really be possible in a linux distribution.
It just means that the BSDs have both their kernel and their full userland maintained by the same team whereas Linux to a certain extent splits responsibilities between the kernel devs and a bunch of other projects.
