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.