Last November I had the pleasure of attending the Museum Computing Network conference – which I highly recommend. It was at a session there that I watched Rosanna Flouty as she presented the diagram below in her slides, illustrating different models for organizing communication.
Some of you will recognize the source – it comes from the work of Paul Baran in the early 1960’s, when he was part of a small group of people thinking
deeply about how to build networks of communication between computers. Baran’s
work, completed at Rand Corporation in Santa Monica, was foundational in the
creation of what would become the Arpanet and, eventually, the Internet.
The core of Baran’s contribution was what we now know as
packet switching – the idea that in order for computer A to send a message to
computer B, you don’t need a fixed electronic “pipe” between them. Instead, you
can break the message up into small pieces, called packets, and pass them from
one computer to another, heading in the direction from A to B. This strategy
has tremendous advantages – for example, messages can be rerouted in the event
one computer fails or becomes overloaded –
but this wasn’t apparent at the time. In fact, many people questioned
whether or not Baran’s idea could work at all.
I’m moderately familiar with Baran’s ideas, at least at a
high level, but when Jennifer displayed the cover of one of Baran’s reports on
the screen, I was quite astonished by what I saw. Here’s the cover:
This was part of the 11-part series that established
the effectiveness of packet switching, or, in the more colorful terminology
used here, “hot-potato routing”. As I mentioned, there was far from universal
acceptance of Baran’s proposal, and this paper was important because it contained
a detailed description of a simulation, written in the programming language
Fortran, that demonstrated not only that packet switching could work, but
exactly how it could work. And look at the authors of the paper: Sharla P.
Boehm and Paul Baran.
Who the heck was Sharla P. Boehm? Paul Baran is generally
considered one of the four or five most important “Fathers of the Internet”,
but who is Sharla Boehm? I can’t remember ever seeing the name before, and I
was determined to try to do some research to find out. Her name is the first on
this paper, so obviously she made an important contribution, but one that seems
to have been largely forgotten.
It took a bit of Google sleuthing, but I was able to find at
least a partial answer. Sharla Boehm was a programmer at Rand in the early
60’s, married to Barry Boehm, who became a well-known computer science
professor. Barry Boehm taught for many years at the University of Southern
California, and was an important theorist in the development of the field of
Software Engineering. (In fact, the name Boehm seemed familiar to me, and
that’s because I had encountered Barry Boehm’s work in my time as a CS
professor.)
In 1996, Barry Boehm wrote an interesting memoir about his
early days in the software industry, entitled “An Early Application Generator and Other Recollections”. He mentions,
in passing:
Coincidentally, my wife Sharla had developed the original packet-switched network simulation with Paul Baran [Baran-Boehm, 1964]).
So there it is – Sharla Boehm wrote the code that
demonstrated the feasibility of packed-switched networks. You can look up the
original paper that she and Baran wrote, and read every line of code that she wrote and see the
actual output from her program.
I couldn’t find any other references online to the work of Sharla
Boehm. Perhaps she went on to write more software, or perhaps she gave that up
and moved on to other things. It would not be realistic to equate her
contribution to that of Paul Baran, but she was there at an important time
doing important, difficult, complex work and apparently doing it well enough
that Paul Baran put her name first on the document. (Ironically, even Barry
Boehm puts Baran’s name first on the reference, and some references to the
article don’t even include Boehm at all.)
So I salute Sharla Boehm and thank her for her contribution.
She helped create the online world we live in today, and it’s wrong to overlook
or forget what she accomplished.
Once I had found the connection between Barry and Sharla
Boehm I searched to see what else I could find. It appears that they are both
alive and well and living in Santa Monica, not far from Rand Corporation where
they apparently met. I did find one more
thing – I searched Flickr to see if I could find a picture of Sharla, and found the photo below from a retirement party for Barry Boehm. There’s Sharla &
Barry in front. I am glad to have a
chance to “put a face” to the name on some 50 year old code that helped to
change the world.
(Addendum, 5/12/2015: more on Sharla's story...)