In time she came to think of the Notetaker as an electronic notebook
for kids to use in school. The idea was doubly ingenious:
It
not only gave
them a paradigm to shoot for, but also established the machine's physical
dimensions. "That told us it had to be light enough to carry around so the
kids could use it to take notes in class, then bring it home and back to
school," Tesler observed.
"Adele had in mind the eMate," he added, referring to a small school-
oriented laptop Apple Computer manufactured years later which bore a
striking resemblance to Kay's original Dynabook sketches.* "She knew it
had to be somewhat heavier than the eMate, though she was hoping it
wouldn't turn out to be what it did, which was forty-five pounds, heavier
than the kid."
Between 1976 and 1978 the Dorado and the Notetaker projects proceeded along parallel but antithetical courses. The Dorado was so
huge in scale that its sheer physical power sometimes overwhelmed
the Garage's efforts at quality control.
Recalled one technician, "It was easy to set a circuit board on fire
because you had this unlimited amount of current. We saw several just
literally burn up. The fans were so powerful you couldn't see where
the smoke was coming out. You could smell it, and you knew that there
was something seriously wrong, but you couldn't tell. So you had to
shut the machine off and pull the boards to find out."
One day, working with a partner, he spotted a wisp of smoke coming off
a board and leaned into the machine to pinpoint its source. Suddenly a
dozen little capacitors went off like incendiary bombs. The technicians
hit the floor. When the devices ceased ricocheting off the walls, they got
to their feet and gingerly eyeballed the errant board. The capacitors, they
realized, had been installed backwards. They had been ticking away like
tiny time bombs until the powerful current finally blew them and the
board to pieces.
Kay's group, meanwhile, focused not on how to pump an incendiary
current through their machine, but how to make it run adequately on
an electrical trickle and with the smallest and lightest components
available.
Doug Fairbairn, who had joined the effort as chief hardware designer,
was aware that Intel, which had long provided PARC with memory chips,
had just introduced a processor-on-a-chip, the 8086. (This was the precursor of Intel's x86/Pentium line of microprocessors, which today power most
*The eMate was a hit in the education market but a failure in the general market.
Apple discontinued the model during its financial retrenchment in 1998.
personal
computers.) With Tesler’s
help, he
worked out a design
in
which
three
8086’
s would serve as the brains
of the
entire machine. They ordered
the first chips Intel produced off the production line and promptly discovered a bug in the product, much to the manufacturers dismay.
"They
said,
We
just gave you the 8086
last week! How
could you report
a bug
already?'" Tesler recalled. But
Intel had
not reckoned with
PARC's
do-it-yourself mentality. Years earlier
the lab
had purchased
a
rare million-dollar machine known as a Stitchweld, which could turn out printed
circuit boards overnight from a digital
schematic
prepared on Thacker's
SIL
program.
"It
turned out that no
one else
using the
8086
had Stitch-
welds. Everyone
else was going
dirough
complicated board designs, so
they
wouldn't know for months
if there was a bug.
But at
Xerox we
gave
them that feedback in a few
days."
Cramming eveiything inside
a portable case
remained their biggest
challenge, for they did not intend
to skimp on
any of the technical features that made
PARC
machines
distinctive. The
Notetaker was to have
a
custom-built display with a
seven-inch diagonal
measurement
and
a
touch-sensitive screen (to
substitute for the
mouse); stereo audio
speak
ers and a built-in microphone;
128,000 bytes
of main
memory;
a
rechargeable battery; and an
Ethernet port.
The
latter, in fact, proved
to
be
a particular
headache.
There
was no
question
of going without it, of
course—PARC
could no more turn out
a
non-networked computer than it
could
go back to using electric
typewriters. But
fitting a standard
Ethernet board—
now boasting
more
than
eighty chips
—
into the
Notetaker's
cramped interior was equally
out of the question.
One
day Tesler crossed the street to
SDD's
quarters in Building 34
and
laid the dilemma before Ethernet's inventor, Bob Metcalfe.
"Why does
it take so many chips?" he
asked.
Metcalfe
patiently explained the function
of
every chip
on
the standard
Ethernet board and why each
was
indispensable. Tesler countered that
plenty of the circuitry could be discarded without undermining Ethernet’s
basic operability. While everybody at
PARC
had their heads stuck in their
high-performance systems, he told Metcalfe, a new world of computer
design was taking shape on the outside. PARC was going to have to adjust.
Tesler’s views on the matter approached the heretical. He was referring
to the hobbyist market, which was indeed exploding. The first annual
West Coast Computer Faire, held in April 1977, had attracted thousands
of young fanatics from all over the Bay Area. These were serious amateurs who built computers named Altair and PET out of kits ordered by
mail, and gathered every weekend to swap shortcuts and software at
gatherings like the Homebrew Computer Club.
They were enchanted with computing's gadgetry as an end in itself, just
as a previous generation had been with their ham radio sets. For many
years yet their mindset would remain alien to those who had learned their
computing at PARC. But Tesler, one of the few PARC engineers familiar
with this niche, already saw they knew plenty that PARC would need to
learn. They had found new ways to move functions out of hardware into
software and to cut corners to save money and space. It wouldn't do to dismiss them as kids playing with toys: Their computers
worked.
"I don't think the chips are all necessary on the Ethernet board," he
told Metcalfe. "These PC guys make their computers so cheap because
they go through all these tricks. We ought to start doing the same."
"That's them," Metcalfe replied. "Our boards have to work perfectly."
"Maybe so, but our computers are worth ten to twenty thousand dollars in parts alone and they
sell
theirs for a hundred bucks. We're trying to do a cheap portable computer and we only have room for
twenty-five chips on each board."
"Then you'll never do Ethernet," Metcalfe replied. "You'll have to wait
for the Ethernet integrated circuit, which is at least five years away."
"We can't wait," Tesler replied.
Then he recrossed the street and set about proving Metcalfe wrong.
Tesler and Fairbairn compressed the Ethernet design as you might wring
out a damp sponge, working it down to twenty-four chips by shunting
more of the work to software than Metcalfe thought possible. The result
was a board that just barely kept up with the three-megabit-per-second
PARC Ethernet—but that did fit inside the Notetaker. ("Metcalfe loved
it," Tesler recalled. "But he was already working on the ten-megabit Ethernet for SDD, so it wasn't relevant to anything he was doing.")
***
The Garage rolled out the first Dorados in 1978 to conspicuous
acclaim. "The Dorado was the only really great computer that PARC
built," judged Ed Fiala, who had played a role in every previous CSL
hardware project. Where the Alto had been slow even for its time, the
Dorado was a speed demon by any contemporary standard. "All the
funky old Alto software ran on the Dorado so fast I got headaches from
not waiting," Jim Morris recalled. "Suddenly I realized that for the first
time,
I'm
the bottleneck."
For a Time Machine, the Dorado was also relatively inexpensive.
Moore's Law was beginning to make its power known in earnest: The
machine cost only about $50,000 in parts while delivering the computing
resources of three powerful Digital Equipment Corporation
VAX-11/780 workstations, which sold for $500,000 each in 1980.
The machine's power almost shook its creators' faith that they were
building something for individuals to use. "It was difficult to think of the
Dorado as a personal machine, since it consumed 2,500 watts of power,
was the size of a refrigerator, and required 2,000 cubic feet of cooling air
per minute," Thacker said later. Yet that, after all, was the essence of the
Time Machine. Potent as the Dorado was, he was still confident that
something on the same scale would be available on a desktop to the individual user within five or ten years, and he was right.