Comparison of BSD operating systems

There are a number of Unix-like operating systems based on or descended from the Berkeley Software Distribution (BSD) series of Unix variant options.

However, they sometimes accept non-disclosure agreements (NDAs) and include a limited number of nonfree hardware abstraction layer (HAL) modules for specific device drivers in their source tree, to support the hardware of companies who do not provide purely libre drivers (such as HALs to program software-defined radios so that vendors do not share their nonfree algorithms).

Derivatives: NetBSD aims to provide a freely redistributable operating system that professionals, hobbyists, and researchers can use in any manner they wish.

It runs on a wide variety of 32-bit and 64-bit processor architectures and hardware platforms, and is intended to interoperate well with other operating systems.

NetBSD places emphasis on correct design, well-written code, stability, and efficiency, where practical, close compliance with open API and protocol standards is also aimed for.

Several security features are available in NetBSD,[13] including IPsec, a homegrown firewall (NPF), a file integrity system (Veriexec), a kernel authorization framework (kauth),[14] a built-in kernel debugger and a number of exploit mitigations like W^X and ASLR.

In June 2008, the NetBSD Foundation moved to a two-clause BSD license, citing changes at UCB and industry applicability.

The OpenBSD policy on openness extends to hardware documentation and drivers, since without these, there can be no trust in the correct operation of the kernel and its security, and vendor software bugs would be hard to resolve.

Examples include the pf packet filter, new privilege separation techniques used to safeguard tools such as tcpdump and tmux, much of the OpenSSH codebase, and replacing GPL licensed tools such as diff, grep and pkg-config with ISC or BSD licensed equivalents.

"[26] OpenBSD has spawned numerous child projects such as OpenSSH, OpenNTPD, OpenBGPD, OpenSMTPD, PF, CARP, and LibreSSL.

Derivatives: DragonFly BSD aims to be inherently easy to understand and develop for multi-processor infrastructures.

The main goal of the project, forked from FreeBSD 4.8, is to radically change the kernel architecture, introducing microkernel-like message passing which will enhance scaling and reliability on symmetric multiprocessing (SMP) platforms while also being applicable to NUMA and clustered systems.

[34][35] Matthew Dillon, the founder of DragonFly BSD, believes supporting fewer platforms makes it easier for a project to do a proper, ground-up symmetric multiprocessing implementation.

[38] In 2020, a new independent project was introduced to collect statistics with the goal of significantly increasing the number of observed parameters.

FreeBSD still uses the image, a red cartoon daemon named Beastie, wielding a pitchfork, as its mascot today.

In 2005, after a competition, a stylized version of Beastie's head designed and drawn by Anton Gural was chosen as the FreeBSD logo.

Although Puffy is usually referred to as a pufferfish, the spikes on the cartoon images give him a closer likeness to the porcupinefish.