Why, FreeBSD is an advanced UNIX-like system for servers, derived from original BSD sources I don't remember exactly when. My first experience was with FreeBSD

Why, FreeBSD is an advanced UNIX-like system for servers, derived from original BSD sources I don't remember exactly when. My first experience was with FreeBSD 2.0 It confirms to recent UNIX standards, such as various POSIXes (pthreads, rt extensions), UNIX98 (I guess), etc. and obviously don't have any Linuxisms, like udev, systemd (thank god!) fuse, you name it, which aren't that important for a server. So you could compile as a port or install as a pre-compiled package almost everything you want for a server. It runs on pair with Linux on network and application performance, in some cases even slightly better. Notably, nginx prior to version 1.0 has been developed on FreeBSD. Nowadays here are a few obvious disadvantages. 1. Driver support is fair - it runs on standard modern hardware, but cannot be compared to Linux with tens of thousands of contributors, it has very small core-team. But it considered much less "marginal" than, say, OpenBSD (which is very clever in its own way) or NetBSD. 2. Vendors doesn't support it, so basically you wouldn't run, say, Oracle or DB2 on FreeBSD (while there is a possibility to install some Linux binaries with emulation). Notably, there is no that "certified, safe Oracle JDK" for FreeBSD, only "unofficial" OpenJDK port. Not long ago it has a reasonable share of all Internet servers and the recent decline isn't due to any quality or reliability issues with FreeBSD, but because "too many Linuxes everywhere". It has some clever technologies of its own, like netgraph, jails+union-fs (which is you could call "chroot-based containers before Docker") native ZFS support, etc. Lots of sane people ran FreeBSD in production, Yahoo is the most notable example. Russians love FreeBSD too - many early ISPs and hosting services has been built on top of it. Lots of developers and contributors are from Russia. So it is modern, reliable UNIX for servers. But not that popular, of course.