I use both FreeBSD and Debian-based Linuxes on a daily basis. (I am mostly a user/developer/sysadmin not an OS-developer).

I want to know what is the motivation behind kFreeBSD? Why people may want to use FreeBSD kernel but avoid the user land?

2 Answers 2


All of the following reasons, are the benefits you get from the FreeBSD kernel:

  • Standardized kernel interfaces:

    • Single /dev implementation via devfs, instead of the 3 discordant ways of handling /dev that Linux provides.

    • OSS as the default sound system (i.e. the standard interface
      supported by almost every Unix-like system around).

    • OpenBSD Packet Filter (pf).

  • Security features, like jails.

  • Support for NDIS drivers in the mainline kernel. On Linux, NdisWrapper is unlikely to make it into the mainline kernel.

  • Support for ZFS in the mainline kernel. Due to license and patent issues, ZFS is unlikely to appear on Linux.

  • kFreeBSD is less vulnerable to legal issues. Licenses are managed in a centralized manner compared to Linux kernel's bazaar-like development model.

  • kFreeBSD developers often have more interest in merging new features rather than spawning forks all along (the port to Xbox is a very good example).

  • kFreeBSD may have better performance and/or stability especially in disk/filesystem areas with ZFS.

  • The FreeBSD kernel might support some hardware which Linux does not support and/or the FreeBSD kernel support might be better (fewer bugs).

Why would you prefer Debian GNU/kFreeBSD to FreeBSD?

  • if you like the Debian package system (or its package set) more than FreeBSD ports (just a matter of preference).

  • If you like GNU userland more than BSDish one (again, just a matter of preference).

  • If you don't have anything against GPL or other copylefted free software licenses, you'll appreciate that useful kernel modules like ext2fs driver, the upcoming reiserfs and xfs, or the upcoming ethernet driver for Xbox are (or will be) compiled in on the default kernel.

  • If you're concerned about running a 100% free system, our commitment to the Debian Free Software Guidelines (DFSG) guarantees that Debian GNU/kFreeBSD doesn't contain any non-free software. In fact, we have removed some non-free binary-only drivers that are contained in the upstream FreeBSD tree.

From the official wiki, there you can find more points on why to prefer the Debian GNU/Linux and not be totally FreeBSD.

  • Thanks, still, as I understand, all these are arguments in favor of FreeBSD, not kFreeBSD, I mean if you want these, why you not use FreeBSD as a whole, or may be I am missing something here?
    – Ali
    Dec 29, 2011 at 16:21
  • see my last line. I will edit my post to include that soon.
    – Hanan
    Dec 29, 2011 at 16:23
  • Yep, so it is mostly a matter of tast, plus some legal/licence issues?
    – Ali
    Dec 29, 2011 at 16:26
  • @Ali; most of the distros out there, are matter of taste or legality isn't?
    – Hanan
    Dec 29, 2011 at 16:27

There are several reasons to avoid FreeBSD userland:

  • Lack of many packages which debian can provide
  • Easily available flash support without any emulation
  • Awareness about Linux applications is, in general, more than awareness about bsd applications.

In no way I am criticizing either of the operating systems. Both serve their purpose well. kfreeBSD is an attempt to combine best of both worlds.

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