planned to come in the final summer just before I finished my MS, at which point I would be working full time at MIT Lincoln Lab and we needed the money since my wife would have to care for our newborn. So, I was not at all interested in pursuing a Ph.D. But Frank Reintjes was insistent and, amazingly, Lincoln Labs decided to offer me a follow-up Ph.D. fellowship to MIT just as they had done for my MS fellowship; this was a first for Lincoln. So I succumbed to the pressure and accepted the Ph.D. fellowship. Two others were also offered the Ph.D. fellowship: Larry Roberts [one of the founders of the Internet, see later— Ed.] and Ivan Sutherland [one of the founders of graphics and an ACM A.M. Turing Award recipient—Ed.] who both became lifelong friends.

What were the first years of your MIT
Ph.D. experience like?

Our Ph.D. qualifier was legendary for its difficulty with 50% of the applicants failing out like flies. My MS at MIT made it easier since the qualifying exam was largely based on the MIT MS curriculum, but full of trick questions. Interestingly Ivan ( Sutherland) came in directly from Caltech (that is, without the benefit of exposure to the MIT MS material directly) and came out on top with one month to study; he is one heck of a smart guy. When I agreed to continue on with a Ph.D. program, I decided I wanted to work with the best professor I knew at MIT, and so called up Claude Shannon (founder of information theory). He surprised me (and shocked my friends) by inviting me to his house in Winchester, MA, USA. I remember the scene looking out on Mystic Lake as an automatic lawn mower (rigged up by Shannon) mowed the grass and his son’s swinging hammock narrowly missed my head. Shannon wanted me to work on a strategy for the middle game in chess as part of a project that he and [AI Founder and Turing Award winner—Ed.] John McCarthy were working on.

How did you gravitate to what is con-
sidered your seminal thesis on packet
communication?

I was looking for a fresh field to work
on. It seemed to me that even Shannon
industrial electronics. So instead of
attending CCNY (City College of New
York) as a daytime student, I attended
at night. My day work was, however,
wonderfully interesting: we were in-
volved in designing and using photo-
electric devices in many applications.

The people in night school were an interesting bunch—after all, who attends night school: crazies, dropouts, motivated students who had to work during the day, and GIs coming back from World War II (this was 1951) who were disciplined and very determined. The professors at night school worked in industry during the day so they had insight into practical matters. I remember a professor bringing a germanium transistor he worked on during the day to class saying “this is a better thermometer than an amplifier,” and began to discuss ways to eliminate the temperature-dependent variations. This combination of combining practical issues with mathematical approaches has always supported my seeking to find intuition and insight behind theory. Claude Shannon, who was then—and still is— my role model, similarly had great insight and physical intuition into why things happened alongside his mathematical approach to problems.

You probably were thinking of getting
a job after CCNY. How did you go to
MIT instead?

I learned one day that an MIT professor was coming to CCNY at 4 P.M. to describe a terrific fellowship that would provide considerable financial support to pursue a master’s at MIT as an MIT Lincoln Labs [a well-known R&D laboratory associated with MIT— Ed.] staff associate. I managed to get off work early that day, but when I asked the MIT professor for an application to the program, he told me they were available from a CCNY professor sitting at the back. The CCNY professor did not recognize me and when I told him I went to night school he said “get out of here.” So I had to contact MIT directly to get a form. That I did and I was fortunate to be awarded the fellowship!

What was it like doing a master’s at
MIT as a Lincoln Labs associate?

My first supervisor at Lincoln was
Ken Olsen, who later went on to
found Digital Equipment and build
the line of PDP computers. I worked
in a group at Lincoln run by Wes
Clark who built arguably one of the
first PCs (the Linc computer). So
there were a lot of brilliant people at
Lincoln; and of course MIT profes-
sors would often visit.

What did you do your MS thesis on?

When I first got to MIT, I was interested in servomechanism systems and automatic control. Yet, my master’s thesis at MIT was on optical readout of thin magnetic films for storage and processing. I made use of the Kerr magneto-optic effect whereby polarized light rotates differently when it reflects off a magnetized surface depending on the direction of magnetization. As a result, one could use polarized light to non-destruc-tively “read” the bits on thin magnetic films (this was before disks). My job was to improve the reading process by amplification and coding. The thesis involved experiments and models and I even constructed a special digital logic using light bouncing off a sequence of thin films. My thesis must have impressed my MS supervisor—Frank Reintjes—at MIT because he insisted that I apply for a Ph.D.

But the idea was that after a Lincoln
Labs fellowship you should work at Lin-
coln Labs as an engineer, right? And
you had a first child coming by then?

That’s right. Our first child was

Being surrounded
by computers at MIT
and at Lincoln Lab,
it seemed inevitable
to me they would
eventually need
to communicate
with each other.