Dealers of Lightning Page 17

  Laboratory dogma maintained that excessively bright light would drive the neutralization effect deep into the selenium layer, like a hammer driving a nail through soft wood. Once the photoconductor thus became too "fatigued" to consistently snap back to a blank, quiescent state, one would see persistent "ghosts" of earlier copies, all transferred together to the blank paper. The objection, being strictly theoretical, was hard to dis­count. "It was only an inkling," Starkweather explained, "because no one had ever tried to expose things in a few billionths of a second before."

  Starkweather’s experiments proved the inkling false. He showed that bathing a photoreceptor with the lasers extraordinarily potent beam for a fraction of a second had the same effect as applying conventional light for the much longer period employed in ordinary xerography. The brevity of the exposure canceled out the strength of the beam, and the selenium survived just fine.

  As for the complaints about the devices' cost, Starkweather figured lasers were bound to come down in price. What, after all, was the laser? A neon tube with mirrors on the ends. A sign that says "Eat at Joe's," unfurled into a straight line. "There's a feeling down in your stomach where you're sure the thing has potential," he recalled of those solitary days and nights. "You have to believe against all odds that the thing will work."

  He also realized he might have an answer to a problem computer science had not yet solved satisfactorily: how to transform a stream of dig­ital bits into something intelligible on paper. A laser could address a pho­tosensitive drum with enough speed to print microscopic dots as fine as 500 to the inch, each one corresponding to a bit of digital data. "I said, what if instead of scanning the image in, as is done in office xerography, I actually just created the data on the computer? If I could modulate the beam to match the digital bits, I could actually print with this thing. I did some test experiments in Rochester, which my immediate management felt was probably the most lunatic project they'd ever seen in their lives. That's when my section manager said, 'Stop, or I'm going to take your people away.'"

  One day in 1970 Starkweather poured out his heart to George White in White's office high atop Rochester's Xerox Square office tower. Starkweather complained that he had been caught in a vice. He felt as though his talents had been wasted and, worse, that they had led his career at Xerox to a dead end.

  He was convinced he could learn to safely manipulate the laser beam in a way that would give Xerox the opportunity to market an entirely new kind of imaging machine. Yet no one in the company seemed will­ing to pay him the slightest heed. He had run out of places to turn.

  There had been one glimmer of hope, he told White. During the summer he had seen an item in the employee newsletter about the new lab being built out in Palo Alto.

  "I think I did the hundred-yard dash to the nearest phone and called out there," he recounted. "They said, "Well, we won't really transfer peo­ple, we're going to hire from the West Coast.' I said, 'Can I come out and tell you what I'm working on?'"

  His persistence won him an interview in California with George Pake, but he came home feeling like the victim of a Catch-22. The lab was fas­cinated with his work, but refused to put in for his transfer. Webster was already aggravated that too many of its top people had been relocated to PARC, Pake explained. 'We won't ask for you," he said. "We don't want to start an avalanche. But we'd take you, if you could happen to get a transfer on your own."

  His immediate boss at Webster had not only turned down his transfer but seemed infuriated at the very idea. "Forget it, Gary," he said, "you're never going to be moved to the West Coast. And you're to stop playing around with that laser stuff."

  White was Starkweather's superior a couple of levels removed, but had heard nothing of this before. He listened to the saga with mount­ing frustration. There was no question that the lab's treatment of Stark­weather had been asinine, exactly the sort of parochialism his own boss, Jack Goldman, was determined to eradicate. White tried to reas­sure Starkweather that there was an answer.

  "Sit tight," he said. "I'll need some time."

  "How much time? This guy's threatening to take all my people away."

  "Just hang in there," White replied. "If he throws rocks at you, try to duck."

  By lucky chance, George White was one of the few people at Xerox who shared Starkweather's appreciation for the laser. Having earned his Ph.D. in nuclear physics from the University of Iowa, he had exper­imented with the new technology himself as a young lab employee at Sperry Rand in 1962. On the strength of that work he had been recruited by a small Pasadena company called Electro-Optical Systems (EOS), which was subsequently sold to Xerox Corporation.

  White also empathized with Starkweather because he had personally experienced the same narrow-mindedness as his younger colleague, at its source. "At EOS we understood lasers and we'd just been acquired by Xerox, so we hitched the two together and showed how you could take a laser beam and expose a xerographic drum," he recalled. The man to whom White demonstrated this first raw achievement of laser xerogra­phy was John Dessauer. "He didn't have the orientation or the context to understand the hottest new scientific breakthrough of the age," White recalled. "He just let it drop."

  White now perceived that fate had granted Xerox another crack at the gold ring. Dessauer was gone. His successor, Jack Goldman, had appointed White head of advanced product development. As one of Goldman's shock troops, White figured there were two components to his job: refining existing copier technology to reproduce conventional images sharper and faster; and perfecting new forms of document imag­ing that the old technology could not handle.

  But these two goals demanded completely different mentalities. 'Webster could spend an infinite amount of money doing their prissy little chemistry and fine-tuning second-order effects in copiers," he said. "But they would never find their way to the new world."

  There was no point in forcing Gary Starkweather, a creature of that new world, to live in the old. Like anyone who tried to pursue a radical new vector at Webster, he was almost certain to get squashed. "Gary's project at best would have limped along without enough power to allow his full productivity," White concluded. "At worst it would have got canceled, and if he wasn't willing to just design lenses and illumina­tors for classical copiers he'd have had to look for another job."

  So White went up the ladder to Goldman. "Starkweather's doing some amazing things," he told his boss. "But he can't thrive at Webster. Nobody will listen to him, and even if they did they'll never do anything that far advanced."

  With scarcely a second thought Goldman lifted the hold on Stark­weather's transfer. Webster be damned. If they could not use the man's talents, he was not going to stand by and see them go to waste.

  Starkweather arrived in January 1971 as PARC employee number 26, assigned to the optical science lab under his old Webster colleague John Urbach. Having scratched and clawed for the assignment he was appalled, as many of his fellow newcomers had been in their turn, by the sheer barrenness of the facility.

  His quarters turned out to be four bare walls and a plug outlet in the lab building fronting on Porter Drive. Say what you would about Web­ster, every project there started out with a gleaming, fully equipped laboratory. By contrast, this place was nothing but vacant spaces parti­tioned off by cinder block walls. Starkweather's glance fell on a strange feature of the walls—they all had some sort of curious rectangular opening down by where they met the floor. "What are those for?" he asked someone.

  The answer was not exactly cheering. The building, it turned out, for­merly had been an animal behavior lab. The openings gave its four- legged inhabitants the freedom to move from room to room. Each room was known by the name of its former inhabitants; there was a dog room, a cat room. "You've been assigned the rat room," they told him.

  At least everyone else also seemed to be starting from scratch. When Starkweather asked one of his co-workers how to get his hands on a few tools, the man flipped him a dog-eared catalog from a s
cientific supply house.

  "Just order what you need."

  That night he was tormented by the thought of having given up his secure, comfortable existence in Webster in favor of . . . the rat room! Would going back to copier work really have been that bad?

  "I was thinking, 'You gave it all up so you could sit alone in this cement block building. You must be an idiot!'"

  Yet PARC's magic did not take long to assert itself. Within a few days he discovered the upside of its ascetic bareness: Money to furnish the rat room seemed to flow in a limitless cascade. At Webster the lab manage­ment had pissed and moaned about the purchase of a single $2,500 laser. Here no one so much as blinked at his order for a $15,000 half-watt behemoth (or for the water lines and pump that had to be specially con­structed to keep it cooled). Rather than make do with an old surplus copier for his experiments, Starkweather ordered up a Model 7000 capa­ble of turning out sixty pages a minute. This duly arrived, attended by a Xerox field technician perplexed at his assignment to set up a top-of-the-line office copier on the bare concrete floor of an unfurnished lab.

  He would have been even more surprised to see what Starkweather was planning to do to it.

  Computer printers had existed for years, yet none had ever been endowed with enough brainpower to take full advantage of the digital bit. They were huge, awkward affairs, messy mechanical systems of solenoids driving hammers into carbon strips, rather like electric typewriters as imagined by a Soviet design team—the epitome of the sort of contraption engineers dismissed as a "kludge" (pronounced "klooge"). From a func­tional standpoint they were slow, clumsy, and lacked any graphic flexibil­ity. Most were limited to printing the 128 characters comprising the so-called ASCII character set (the acronym stood for "American Stan­dard Code for Information Interchange").

  ASCII encoded every numeral and English-language letter, along with a handful of fine-setting characters, as a sequence of seven digital bits— hence the constraint to 128 characters, the maximum number that can be expressed in seven binary digits. If you wanted something unusual, like a German ü or French ç, much less lettering of an unconventional size and a fancy typeface, you were out of luck. Computer designers were happy enough that the seven-bit code at least allowed them to have upper- and lower-case letters.

  Starkweather’s assignment was to build a machine that could print on paper almost any image a computer could create. The first problem he needed to solve was how to build a machine that could make, as he put it, "intelligent marks on the sheet at a page a second" to match the 7000’s capacity. This was essentially a speeded-up version of the task he had been working on at Webster all those long years. Solving it at PARC took another eleven months, or until November 1971.

  His design was deceptively uncomplicated. At its heart was a spinning disk about the size and shape of a hockey puck. Milled around the rim were twenty-four flat mirrored facets, which gave it the appearance of a cross-sectional slice of a discotheque ball. As the disk spun, each mirror picked up the beam of the laser and redirected it onto the photoreceptor as a sweeping line of modulated light. (Think of a lighthouse beam sweeping horizontally across a wall'—thousands of times per second.) The process produced an image that looked clean and solid to the naked eye, but was in fact comprised of millions of minute dots etched on the photoreceptor (and transferred in turn to a blank page) at a resolution of five hundred horizontal lines to the inch.

  Considerable fine-tuning was necessary to keep this complicated sys­tem humming along. Assembling the hardware and synchronizing the components was like getting a herd of cats to sing in unison. Since the polygonal disk spun at 10,000 revolutions per minute (the original glass prototype was soon replaced by aluminum), even the way the facet edges "paddled" the air produced measurable resistance. The laser itself had to be modulated up to fifty million times a second by a "shut­ter" fashioned from a polarizing filter driven by a $10,000 piezoelectric cell. And because it had to conform to the speed of the copier, Stark­weather's laser apparatus had to mark more than 20 million dots on a page every second.

  Still, the most troublesome problem was not electronic. Instead it fell squarely within the domain of traditional optics. Starkweather knew that if the mirrored facets were even microscopically out of alignment, the scan lines would be out of place and the resultant image distorted or unintelligible, for the same reason a wobbly tape deck makes an audio-cassette warble as though recorded under water. To produce clean images, he calculated, the facets could not be out of vertical alignment by more than an arc-second—a microscopic variance. In visual terms, the mirrors could not be off by more than the diameter of a dime as viewed from a mile away.

  Disks fabricated to such an exacting standard would cost at least $10,000 each—assuming this were technically possible, which Stark­weather doubted. It was true that there existed servo-mechanical and optical devices that could quite effectively redirect an errant scan back in place. But they were even more expensive and, as a further drawback, meant adding another complicated and failure-prone component to his printer. Starkweather understood that the tolerance issue was critical. If he could not solve it, he would have designed a machine that could not be cost-effectively manufactured.

  For more than two months he wrestled with the puzzle. "I would sit and write out a list of all the problems that were difficult. One by one they would all drop away, but the mirrors would still be left."

  One day he was sitting glumly in his optical lab. The walls were painted matte black and the lights dimmed in deference to a photoreceptor dram mounted nearby, as sensitive to overexposure as a photographic plate. Starkweather doodled on a pad, revisiting the rudimentary principles of optics he had learned as a first-year student at Michigan State. What was the conventional means for refracting light? The prism, of course. He sketched out a pyramid of prisms, one on top of another, each one smaller than the one below to accommodate the sharper angle of neces­sary deflection. He held the page at arm's length and realized the prisms reminded him of something out of the old textbooks: an ordinary cylin­drical lens, wide in the middle and narrowed at the top and bottom. "I remember saying to myself, 'Be careful, this may not work. Its way too easy.' I showed it to one of my lab assistants and he said, 'Isn't that a little too simple?'"

  It was simple. But it was also dazzlingly effective. Starkweather's brainstorm was that a cylindrical lens interposed at the proper distance between the disk and the photoreceptor drum would catch a beam coming in too high or low and automatically deflect it back to the proper point on the drum, exactly as an eyeglass lens refocuses the image of a landscape onto a person’s misaligned retina.

  "I ran to the phone and called Edmund Scientific, my supply house, gave them my credit card, and bought ten bucks' worth of war surplus lenses," he recalled. "I could hardly sleep the two days before they arrived. But then they came, I put them in, and sure enough they worked." The lens scheme was foolproof. It involved a simple physical relationship, so it could never fail. It had no moving parts, so it could never malfunction. And it permitted the polygonal disks to be stamped out like doughnuts—not at $10,000 apiece, but $100.

  "The mirrors no longer had to conform by the diameter of a dime at a miles distance," Starkweather recalled. "They could be off by the diameter of a tabletop, which was a standard anyone could meet. I made a lot of discoveries building that machine, but it was the cylindri­cal lens that made me say 'Eureka!'"

  Starkweather’s finished printer was a large, bulky machine. His open arrangement of plump black-tubed lasers, mirrors, and wires sat atop the clean but stolid Model 7000 copier like a ridiculous hat on a dowa­ger aunt. He christened the machine SLOT, for "scanning laser output terminal."

  "I would have called it the scanning laser output printer," he said, "but that wouldn't have made a very good acronym."

  Building the SLOT solved only half the riddle of how to convert dig­ital images to marks on paper—the back end, so to speak, of how to apply toner on
ce the image was delivered to the laser beam. The front end involved translating the computer's images into something the laser could actually read.

  That half was solved by the invention of the so-called Research Char­acter Generator (RCG), another healthy piece of iron and silicon, by Lampson and a newly hired engineer named Ron Rider. The RCG, which stood several feet high and nineteen inches wide, and housed 33 wire-wrapped memory cards holding nearly 3,000 integrated circuits, was a sort of super memory buffer, spacious enough to accept a digital file from a computer, evaluate it scan line by scan line, and tell the printer which dots to print at which point. This generated on paper an image cre­ated by pure electronics.

  Today this procedure is trivial. Memory is so cheap that the computer and printer both come with enough to hold several pages at a time. As a page comes in from a word-processor program, it is fitted into a print buffer the way craftsmen of the old printing trades clamped lines and columns of leaded type into rectangular frames. Once in memory, the page image can be manipulated in an almost infinite number of ways. It can be fed to the printer narrow or wide end first, backwards, upside- down, or wrapped around a geometrical design. The most unassuming desktop computer can store character sets in dozens of font styles and sizes, any of which can be summoned at will and applied to a document as a paintbrush swipes color at a wall.