I noticed that, too: the author doesn't mention the many-splendored versions of *BSD. My personal favorite is FreeBSD.
I like Linux, but I have mixed feelings about systemd, especially when I discovered that systemd runs its own DNS server, which prevents the DNS server I wrote from binding to port 53 using INADDR_ANY. Instead, I had to write code to enumerate the interfaces & corresponding IP addresses & bind to each one separately. Systemd's decision to run their own DNS server is a bit of overreach, IMHO.
I like Linux, but I have mixed feelings about systemd, especially when I discovered that systemd runs its own DNS server, which prevents the DNS server I wrote from binding to port 53 using INADDR_ANY. Instead, I had to write code to enumerate the interfaces & corresponding IP addresses & bind to each one separately. Systemd's decision to run their own DNS server is a bit of overreach, IMHO.