Plus Ken Arnold was originally part of the Ingres group, which famously had the only ArpaNet connection on campus at the time (Ing70 - which I have forgotten what it's one letter 'Berk-Net' id was -- Mary Ann might remember - i.e. all external email was shipped across the Berknet to Ing70 for processing).

Actually, I don't recall Ken actually working on Ingres, although it's not impossible — he certainly did work at Britton Lee, which was an Ingres spin-off. But lots of people in the department had access to our machine, almost certainly including Ken. But resources were limited and the entire department had to compete for the two terminal lines available at the time, which is why I wrote delivermail (later sendmail) in the first place.

The "one letter berk-net id" of ing70 was "i". At the time of the ARPAnet it was running a rather customized V6 that (if I recall correctly) we got from Greg Chesson. It was connected via a VDH (Very Distant Host) interface to the IMP at LBL — essentially a six-foot-high 9600 baud modem.  ingvax was "j", but the ARPAnet code never ran on that hardware.

eric