I am glad to have found the following in the TUHS Archive.

I suppose the following was released under the BSD license.

Here are extracts from 2.8BSD /usr/kernel/sys/sys/sys1.c

                      Introduction to
               Berkeley Kernel Modifications
                   Unix - Seventh Edition

              Last PDP-11 Kernel Distribution
                         July, 1981


                         Bob Kridle

  Electrical Engineering and Computer Sciences Department
            University of California at Berkeley
                Berkeley, California  94720


                     William F. Jolitz

                  U. S. Geological Survey
                Office of Earthquake Studies
               Menlo Park, California  94025


                          ABSTRACT

          This tape contains  work  done  at  Berkeley,
     USGS,  and  several  other  sites  in the last two
     years to make the UNIX - Version 7  PDP-11  Kernel
     usable in our environments.  Appended is a list of
     most of the  modifications  made  to  the  kernel.
     Since  Berkeley does not plan to buy any more PDP-
     11s as UNIX vehicles and is  planning  to  replace
     the existing PDP-11 systems with VAXen in the next
     year, we are rapidly  losing  interest  in  PDP-11
     work.   The  system included here is by no means a
     finished product, but it  is  unlikely  that  much
     more significant progress will be made.  It is our
     purpose to make available all work done until now.
     The  most  recent  addition  to  this  system is a
     mechanism to allow overlaid kernel text permitting
     fairly  robust systems to be run on non-separate I
     and D machines such as the  PDP-11/34.   In  addi-
     tion,  more  device handlers have been added.  The
     system should boot on almost anything.

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