made us think it would be a good idea
to pursue the question of how to build
what came to be called the paperless
[CoNTiNUed FroM p. 112]
You’re talking about robert Taylor,
who managed the Computer systems
Laboratory at parC.
did you have a sense of how revolution-
ary alto was as you worked on it?
Oh, yes, we knew it was revolutionary. We built it with the very first semiconductor dynamic RAM, the Intel
1103, which was the first memory you
could buy that was less than a tenth of
a cent a bit. As a result, we realized we
could build a display that was qualitatively better than what we had at the
time. We had character generator terminals, and some of them were quite
nice. But they were limited in various
ways, whereas the Alto had the property that anything you could represent on
paper, you could put on the screen. We
knew that was going to be a big deal.
You were also involved in the invention
of the ethernet.
The Ethernet grew out of the realization I had of how to provide a
network for the Alto. We had been
studying the ALOHA network, a radio
network that was used to connect the
various Hawaiian Islands. The limitation was that when a transmitter
started to transmit, it could no longer
receive anything. One night I was lying in bed thinking about the problem
when I had this sudden realization
that if you used a more limited media,
say, the coaxial cables used in cable
television, the transmitter could not
only hear what it transmitted, it could
also tell whether what it thought it put
on the wire was the same as what actually got put on the wire.
so if another transmitter was interfer-
ing, it could drop back and retransmit
“the alto had
the property that
anything you could
represent on paper,
you could put on
the screen. We knew
that was going to
be a big deal.”
That idea was refined by Bob Met-calfe and Dave Boggs into what we
knew as the Ethernet. Of course, the
Ethernet in those days was quite different than it is today.
You joined Microsoft in 1997 to help
establish the company’s research lab
in Cambridge, england, and were later involved in the development of the
tablet pC, a subject that’s much in the
news of late.
The line of thinking about tablets actually started at DEC [Digital
Equipment Corporation]. We built a
tablet called Lectrice back in the early 1990s, primarily as an electronic
book reader. When I returned to the
U.S. from my two-year assignment
in Cambridge, I was working with a
group in Redmond that was trying
to build an electronic book reader.
That didn’t work out too well, but it
evolved into the idea of building a
tablet PC. Of course the view there
was it would be great to have a device
that didn’t require a keyboard.
what do you make of the persistence
of the keyboard in spite of the alterna-
tives that now exist?
Typing is so much faster than virtually any other way of entering information into a computer, so I don’t expect that to change. There’s only one
thing that can be better, and that’s to
use a different set of muscles—the
tablet allows you to do that. You’re
holding a stylus and writing or drawing with it, and the interaction can be
More recently, you’ve been working on
I’ve been using field-programmable
gate arrays (FPGAs) to explore multicore
architectures. For a long time, it was
impossible for academic researchers—
or even people working in industrial
labs—to design their own chips. It’s
now possible to build a nontrivial multicore computer, with something on the
order of 15 cores, on a single FPGA on a
board that’s available for $750.
what does the future hold for you in
terms of research? are you tempted to
go back and continue working on the
If I have a good idea I might go back
to it. But right now I’m quite happy
with what I’m doing, and there’s a
considerable amount of work to do in
this area. So I think I’m set for the next
Leah hoffmann is a brooklyn, ny-based technology
© 2010 ACM 0001-0782/10/0700 $10.00
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