Net2

Net/2 was supposed to be the `uncontaminated' source code written by CSRG at Berkeley and others. However, when BSDi released their open-source product BSD/386, USL sued them because it was based on Net/2 and USL believed that portions of Net/2 were contaminated.

When the case was settled out of court in 1994, Berkeley and BSDi agreed to stop distributing the following files from Net/2:

/sys/kern/init_main.c
/sys/kern/kern_clock.c
/sys/kern/kern_exec.c
/sys/kern/kern_exit.c
/sys/kern/kern_sig.c
/sys/kern/kern_synch.c
/sys/kern/subr_rmap.c
/sys/kern/sys_generic.c
/sys/kern/sys_process.c
/sys/kern/sysv_shm.c
/sys/kern/tty.c
/sys/kern/tty_subr.c
/sys/kern/vfs_syscalls.c
/sys/sys/buf.h
/sys/sys/proc.h
/sys/sys/shm.h
/sys/sys/buf.h
/sys/ufs/dinode.h
/sys/ufs/indode.h
/sys/ufs/ufs_bmap.c
/sys/ufs/ufs_disksubr.c
/sys/ufs/ufs_inode.c
/sys/ufs/ufs_vnops.c
and the cpio source.

For more information about Net/2, see Twenty Years of Berkeley Unix by Kirk McKusick. You may also like to read Kirk's comparison of Net/2 and 32V, made at the time of the lawsuit.