FreeBSD and Linux Kernel Cross-Reference

This site provides source code browsing for the FreeBSD and Linux kernels, based on the software provided by the LXR Project.

The original aim of this site was to make it easier for FreeBSD developers and users to explore the FreeBSD source code, the source code of FreeBSD-derived systems such as Darwin, as well as gain a greater understanding of the implementation of related services in NetBSD, Plan 9, and Linux. Understanding the approaches (and quirks) of other implementations is important in helping to address issues of portability and code clarity, not to mention abstraction and architecture. However, it is now seeing significant use from a much more broader community.

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FreeBSD
FreeBSD 14-CURRENT (head)

FreeBSD 13-STABLE (stable/13)
FreeBSD 12-STABLE (stable/12)
FreeBSD 12.0-RELEASE (releng/12.0)

FreeBSD 11-STABLE (stable/11)
FreeBSD 11.0-RELEASE (releng/11.0)

FreeBSD 10-STABLE (stable/10)
FreeBSD 10.0-RELEASE (releng/11.0)

FreeBSD 9-STABLE (stable/9)
FreeBSD 9.0-RELEASE (releng/9.0)

FreeBSD 8-STABLE (stable/8)
FreeBSD 8.0-RELEASE (releng/8.0)

FreeBSD 7.0-RELEASE (releng/7.0)

FreeBSD 6-STABLE (stable/6)
FreeBSD 6.0 (releng/6.0)

FreeBSD 5-STABLE (stable/5)
FreeBSD 5.0-RELEASE (releng/5.0)

FreeBSD 4-STABLE (stable/4)

FreeBSD 3-STABLE (stable/3)
Linux
Linux 2.6 git development branch
Plan 9
Plan 9
Mach
CMU Mach Kernel 84
Apple Darwin
Darwin 7.0 XNU (xnu-517) - Mac OS X Panther
NetBSD
NetBSD (HEAD)
NetBSD 5.x (netbsd-5)
NetBSD 4.x (netbsd-4)
NetBSD 3.x (netbsd-3)
NetBSD 2.x (netbsd-2-0)

Robert Watson

The Design and Implementation of the FreeBSD Operating System, Second EditionNow available: The Design and Implementation of the FreeBSD Operating System (Second Edition)