BBN networking code in 4.3BSD
Bob Walsh
> From: mcku...@ucbvax.ARPA (Kirk Mckusick)
> Subject: Status of 4.3BSD
> Date: 6 Sep 85 00:23:29 GMT
> Keywords: 4.3BSD
> To: unix-w...@brl-tgr.arpa
>
> At the June Usenix conference we announced that we expected to begin
> shipping production 4.3BSD systems in mid to late August. Two weeks
> after the Usenix meeting we shipped what we then thought was our beta
> distribution tape. The following week our primary funding agency, DARPA,
> informed us that we were required to replace our version of TCP/IP
> with that supplied by BBN. After a great deal of discussion, we
> agreed to include both implementations and let individual sites
> choose which version they wanted to configure their kernels to use.
> BBN delivered their implementation to us on August 30th. We must now
> put together another beta tape with the new kernel and restart the
> beta testing (in particular we must give BBN time to work on their
> networking code, as it does not interface to many of the utilities).
> Assuming that we are not required to make any further changes to the
> distribution, we now anticipate that full distribution will begin
> before the end of the year.
...
> Kirk McKusick
> CSRG
? work on the networking code and interface it to utilities?
The BBN code for 4.2 UNIX could almost be dropped right in. The exceptional
programs were those that knew about implementation specific information
(/etc/route because the ioctl to install a route encoded the size of a routing
structure and the routing structure was augmented with additional information,
netstat so that it could interpret protocol connection state data structures...)
Standard utilities like rwho, ftp, telnet, rlogin... required neither change
nor recompilation.
With the 4.3 distribution, I modified netstat to be smart enough to determine
which implementation was in use and to examine the state information
accordingly. Programs like route that know about kernel data structures are
being distributed knowing about data structure definitions that meet both
implementation's requirements. So, with 4.3 BSD one could switch back and
forth at will by just changing a line in the system configuration.
If I am wrong, please correct me and let the people at BBN know. Though
I am entering graduate school this fall, I will be reading my mail and
advising Karen Lam, my successor at BBN.
For system managers, I should say that the two systems do provide networking
support within UNIX. Both 4.3 systems work well. One can succesfully telnet,
ftp, rcp, rsh, and all the rest. Many sites will not notice which they run.
The goal is to support those sites which would notice.
One should not have the impression that this code is wet behind the ears, though
parts of it are new. When Berkeley distributed 4.1BSD, one could get a
networking tape from BBN and provide themselves with a networking system. The
BBN 4.2 code was not widely distributed because BBN did not want to get into
the UNIX license verification business. However, it was used at Internet sites
that required some of its extra functionality and more reliable performance
over SATNET. Though similar in that they provide a transport layer, they
do not always share the same algorithms or external properties. But that is
a topic for a longer message.
bob walsh