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Aren't the kernels amongst the BSDs different enough that effort is split? With GNU/Linux, the variations is much more in the packaging than the kernels, no? Co

Aren't the kernels amongst the BSDs different enough that effort is split? With GNU/Linux, the variations is much more in the packaging than the kernels, no? Couldn't I download a vanilla kernel, compile it, and boot any Linux distro with it?

zymhan 6y ago
Yes but part of that is inherent in what BSD considers a kernel as well.
spijdar 6y ago
Well, yes/no. There are different ways to configure the kernel, and some distros/userlands require specific kernel features which may or may not be default. Your general point is still true, though. They are different enough that some of the work is split, however there's significant code sharing in things like device drivers and the like. Ultimately each being very different is usually seen as a positive. While the <n> Linux distros are spending significant hours optimizing essentially the same userland for minor differences in use cases, the different BSDs have very different goals and results. OpenBSD has an emphasis on making a lean and consistent base system with comprehensive documentation, NetBSD has excellent tooling for cross-compiling, and a comparatively more modular kernel that lends itself to experiments like rump-kernels. I'm less familiar with FreeBSD but it's tended to emphasize features like ZFS and its own robust container solution. In some cases these features are contradictory, as OpenBSD would be (I imagine) very reluctant to merge NetBSD's in-kernel Lua module support, or NetBSD's multithreaded "high performance" implementation of the firewall pf, "npf", in favor of its own much simpler and more secure pf. OTOH NetBSD has a stronger emphasis on backwards compatibility which somewhat limits their ability to make broad changes to the userland as OpenBSD has. Then, one is much more likely to be able to run old NetBSD binaries on new kernels. :) Each has its pros/cons, and attracts its own users and developers. The distinguishing thing about *BSDs is the base userland and kernel are deeply intertwined, giving each more freedom to deeply tie userland tools to special kernel functionality. There are pros and cons to this too, but this means that, for example, one can use "ifconfig" to connect to WPA2 WiFi networks on OpenBSD with no other tools required, as the ifconfig userland is always released alongside a matching kernel. The various net-util packages shipped for linux have suffered from having to operate as "external" tools interfacing with a range of kernel versions. (of course, now the situation is better with ip/iw, but it sure took long enough)

zymhan 6y ago

Yes but part of that is inherent in what BSD considers a kernel as well.

spijdar 6y ago

Well, yes/no. There are different ways to configure the kernel, and some distros/userlands require specific kernel features which may or may not be default. Your general point is still true, though. They are different enough that some of the work is split, however there's significant code sharing in things like device drivers and the like. Ultimately each being very different is usually seen as a positive. While the <n> Linux distros are spending significant hours optimizing essentially the same userland for minor differences in use cases, the different BSDs have very different goals and results. OpenBSD has an emphasis on making a lean and consistent base system with comprehensive documentation, NetBSD has excellent tooling for cross-compiling, and a comparatively more modular kernel that lends itself to experiments like rump-kernels. I'm less familiar with FreeBSD but it's tended to emphasize features like ZFS and its own robust container solution. In some cases these features are contradictory, as OpenBSD would be (I imagine) very reluctant to merge NetBSD's in-kernel Lua module support, or NetBSD's multithreaded "high performance" implementation of the firewall pf, "npf", in favor of its own much simpler and more secure pf. OTOH NetBSD has a stronger emphasis on backwards compatibility which somewhat limits their ability to make broad changes to the userland as OpenBSD has. Then, one is much more likely to be able to run old NetBSD binaries on new kernels. :) Each has its pros/cons, and attracts its own users and developers. The distinguishing thing about *BSDs is the base userland and kernel are deeply intertwined, giving each more freedom to deeply tie userland tools to special kernel functionality. There are pros and cons to this too, but this means that, for example, one can use "ifconfig" to connect to WPA2 WiFi networks on OpenBSD with no other tools required, as the ifconfig userland is always released alongside a matching kernel. The various net-util packages shipped for linux have suffered from having to operate as "external" tools interfacing with a range of kernel versions. (of course, now the situation is better with ip/iw, but it sure took long enough)