O
ne morning in 1978
dozens of PARC
scientists arrived at
work to discover their
Altos were
dead.
At first this
did
not raise any alarm.
The crash
of an Alto
was a
common
enough phenomenon and easily remedied:
One
simply reached over and
pressed
a
reset
switch Thacker had
obligingly
provided
on
the console.
The
machine then rebooted from a
spare disk
coded with
a
copy of
the
operating system or, if one was not
available,
remotely by
Ethernet.
For
the first hour or so no one even suspected that the crashes might
be part
of
a more general crisis. But it soon became obvious
that
the
Altos
had been infected by an entirely
new
quirk. They booted
up
fine,
but step
away from your machine for
even
a few minutes—and it
crashed again. Reboot again, fine. Leave it idle . . . and death.
Soon
the
first
and second floors of 3333 Coyote
Hill
Road were fairly echoing
with
voices raised in apprehension and protest.
Hey,
what's the matter with my Alto?
. . .
Something go wrong with
yours, too?
Mine
was dead when I came in!.
. .
Mine
too!
. . .
And
mine!. . .
What's
going on? There must have been a
hundred
machines
crashed when we came in this morning!
At length someone in CSL put two and two together. "You know,
Shoch and Boggs were here all night."
"Working on what?"
"Something to do with the Ethernet.
. .
."
And so the summons went out. John Shoch, who had indeed been
working all night on a network diagnostic program with Dave Boggs,
had scarcely dropped off to sleep when he was jarred awake by the fire
call from PARC. Machines were dead all over the building. Did he
happen to know anything about it?
Uh-oh,
he thought to himself.
Something must have gone wrong with
the Worm.
By the late 1970s much of the work in PARC's two computing labs
entailed elaborating on the inventions produced during its first few
glorious years. Inventing the Alto and Ethernet was like seeding a
field. Now it was time to harvest the crops
—
in other words, to look
more closely into how these systems worked in the real world and in
concert.
John Shoch decided to tug on one of these threads for his Stanford doctoral thesis. His plan was to study how a network behaved under various
message loads and traffic patterns. But it would not be enough to watch
it operate under normal conditions. The really interesting thing would be
to see what happened if you really pounded on the system, loading it to
the absolute limit to see if it blew a gasket.
He knew he had a major advantage over other students of network theory. He had daily access to the Ethernet, then the world's largest and
busiest computer network. The only question was whether Xerox would
let him publish what he learned.
This was not an idle consideration. Xerox was acutely aware that its
wealth flowed from secrets and property rights. Behind its domination of
the copier market
—
which was waning but still strong—were a handful of
ferociously defended patents, as well as other inventions so critical they
had never been exposed to the public scrutiny of a patent application.
Instead they were locked in a vault as secure as the one that safeguarded
the recipe for Coca-Cola. By 1973 the company had assigned a corporate
patent lawyer
to
PARC
full-time and
decreed
that even technical papers
were
to be vetted by counsel and cleansed
of
any inadvertent proprietary
disclosures before they could be submitted
to
professional journals.
On
rare occasions
PARC
issued
technical
papers on its own.
These
were known as "blue books" from the
color
of the horizontal stripes
across the covers. But for the most part
the
legal department controlled
the publication of research with an iron
hand. So
much creative talent
went into the building on Coyote Hill
Road
and so little information
came out that
PARC,
recalled one
former
manager, was sometimes
called "the black hole of computer
science."
PARC
researchers participating in
conferences
and other public events
had to carefully comply with the
company's
paranoid rules.
They
did not
always
avoid embarrassment. One
of the
more delicate situations
involved the Ethernet team of Shoch,
Bob
Metcalfe, and several other
engineers.
As
an
ARPANET
host
location PARC
was honor-bound to
help address any technical problems
cropping
up during construction of
the nationwide system. Unfortunately,
Xerox's
lawyers had given the
Ethernet
engineers strict orders to keep
to
themselves everything they
knew.
This quandary first surfaced in 1973, when
Metcalfe
attended an
ARPANET
conference at Stanford.
One
issue under discussion arose
from the proliferation of independent "local area networks," or
LANs,
similar to the Ethernet at PARC. These networks' technical standards, or
protocols, were often incompatible with each other and with the
ARPANET
itself. The question was how to coordinate them so data
could smoothly pass from one to another via the
ARPANET
backbone—
a
critical step toward
ARPA's
goal of expanding its network into a larger
and more comprehensive system linking computers everywhere
—
transforming it, in other words, into an "internet."
For the
ARPANET
's
technical honchos this question was still largely
hypothetical. So far there were only a few operating
LANs
sophisticated
enough to tap into the main network. For
PARC,
however, it was already
a pressing issue. At Stanford Metcalfe held his tongue, but he returned to
his office convinced he could not wait for
ARPA
to solve the problem.
Xerox was already planning to use the Ethernet to link corporate locations all over the country—indeed, the globe. Data packets would have to
traverse outside systems on their way from one local Xerox loop to
another, like trucks hopping on the interstate en route from California
factories to New York retail shops.
"We have a more immediate problem than they do," Metcalfe confided to Shoch, "because we have more networks than they do. We're
going to have to build an internet protocol ourselves."
Working with Boggs and Ed Taft, a mathematician from Harvard, Metcalfe and Shoch came up with a solution they called the PARC Universal
Packet, or "Pup." The basic idea was to enclose a data packet in a sort of
electronic envelope consistent with the protocol of the transporting network—radier like a child's birthday present wrapped and tagged with a
Federal Express airbill for transport by its planes and trucks. As the
packet moved from network to network, it could be further wrapped in
any number of network-specific capsules. By the time it reached its destination the various envelopes would have been stripped away, leaving
the original message to be read.
In the year they spent developing and testing Pup over dozens of variant networks, the PARC engineers moved well ahead of the ARPANET
team in their technical expertise. This was unsurprising. Their sandbox,
comprising nearly 500 host computers scattered around the country, was
already much bigger and busier than the ARPANET.
*
Moreover, PARC
was immune to the ARPANET
's
lumbering bureaucracy.