[colonelspace]

Please do break down the differences.

[johnisgood]

I could not hold myself back, so I already elaborated on OpenBSD and DragonflyBSD here (albeit it is non-exhaustive): https://news.ycombinator.com/item?id=45714491 :D

I left out FreeBSD from that comment, which has its own set of innovations: Capsicum (capability-based security framework), Jails (OS-level virtualization/containerization which predates Docker by over a decade), MAC Framework (Mandatory Access Control for fine-grained security policies), GEOM (modular disk I/O framework), Linuxulator (Linux binary compatibility layer), ZFS (FreeBSD has arguably the best ZFS implementation outside of Solaris), bhyve (type-2 hypervisor), and so forth.

Userland tools include iocage/bastille (jail managers), poudriere (package building), jemalloc (default allocator which focuses on fragmentation avoidance and scalability) among many others.

Each BSD really does have its own character. FreeBSD leans toward performance and production use, OpenBSD toward security and correctness, NetBSD toward portability and clean design, DragonflyBSD toward alternative SMP approaches!

(illumos/OpenIndiana is quite interesting, too (see DTrace, Doors IPC, Zones, SMF, Contracts, Event Ports, RBAC)).

[cyberpunk]

FreeBSD uses OpenZFS (which was previously called ZoL (ZFSOnLinux), afaik) -- so it's the same implementation as e.g ubuntu.