Technology - Circuits
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June 17, 1999

Reinvent the Wheel? This Software Engineer Deconstructs It

By KATIE HAFNER

When the Sony Corporation put Aibo, its $2,500 robotic dog, up for sale on its Web site last month, John Wharton was determined to get one. After two hours of trying to get past the congestion on the site, he finally placed his order.



Peter DaSilva for The New York Times
SECRETS OF FURBY - John Wharton ``reverse-engineers'' a Furby. At right, a partly dismantled Furby and an intact toy sit in front of a computer, which is used to analyze the design.
Wharton has no plans to give his mechanical-electronic dog away as a gift, to keep it around the house as a virtual pet or to preserve it as a collector's item. After a period of clinical observation, Wharton intends to apply screwdriver and pliers, taking it apart chip by chip, motor by motor, sensor by sensor.

Wharton is a reverse engineer. For pure pleasure, he has dissected VCR's, answering machines, floppy disk drives, cellular phones, camcorders and laser printers. His most satisfying private project of late is the painstaking dissection of Furby, the electronics-laden toy, which Wharton views as a tour de force in compact, highly intricate yet cost-efficient engineering. To date, he has dismantled five of them, all to varying degrees, all with different technical goals in mind.

Wharton, who is 44, supports himself, and a handful of expensive and eccentric hobbies, mostly by working as a highly paid forensic engineer.

Wharton is hired as a high-tech detective by law firms whose corporate clients are involved in patent disputes. They call on Wharton to take a finished product and trace it back through thousands of steps to its original specifications to see where an infringement may lie. In the last 10 years, he has been hired to reverse-engineer video game players, home health devices and several variations on PC circuitry.

A bearded man with long graying hair, Wharton has maintained a Zelig-like presence in Silicon Valley for more than two decades.

In 1978, as a 23-year-old engineer at Intel, he was the architect of a computer chip called the 8051. Along with its various offspring, the 8051 is the highest-volume microprocessor the company has ever introduced.

And in 1995, Wharton played a small role in the capture of Kevin Mitnick, the computer hacker who recently pleaded guilty to charges of computer fraud and wire fraud.

In 1981, Wharton quit his job at Intel and became a consultant, in part because he was eagerly anticipating the debut of David Letterman's show, which would be broadcast until 2 A.M. each night. Having to get up in time to make the 8:10 A.M. sign-in at Intel every day would deprive him of sufficient sleep.

Safeguarding patents by retracing the inventor's digital steps.


Wharton works from his house in Palo Alto, Calif., where he lives with a cat named Zero. "People ask me if I have a dog named One," he said. (He does not.) His newest pet, Roo-Roo, a gray and pink Furby with black spots, is the only Furby to have escaped the pliers. "He was my firstborn," Wharton explained, tenderly.

Wharton's name is on the short list of engineers in Silicon Valley whom law firms turn to when they need expert technical help. He does not disguise his self-confidence. David Larson, a partner at Wilson Sonsini Goodrich & Rosati, a Palo Alto law firm that has on occasion retained Wharton as its expert engineer, said that behind his disheveled appearance was an extraordinary intelligence, accompanied by "the arrogance that comes with being so knowledgeable about certain things." Wharton's fees -- up to $350 an hour -- occasionally rival those of the lawyers who hire him.

But those who know Wharton's work say he is worth every cent. "When John is trying to incorporate a new fact about something he's reverse engineering, he can remember 10 other aspects of the design that will be affected," said Brian Case, a fellow reverse engineer who has worked with Wharton on several technical projects.

"He arrives at his solution faster. That's where his genius comes in."

The concept of reverse engineering can be likened to being given a slice of cake, Wharton said, then being told to unbake it and to produce the recipe and a list of the raw ingredients in the process. "Baking a cake might take a lot of skill, but unbaking a cake is a more interesting problem," Wharton said.

In Wharton's view, reverse engineering is the ultimate puzzle. The electronic age, he noted, has made the process of ascertaining whether a patent has been encroached upon much more difficult.

"It used to be that machines were physical," he said. "You could study the gears and levers of a cotton gin and pretty much figure out how it worked. But nowadays the things that pass as machines are virtual. Cams and levers and drive belts are replaced by source-code statements and subroutines and disk files."

Hence the need for hired guns like Wharton, people who can extract the bits and turn them back into a form that judges and juries can understand.

To understand reverse engineering, Wharton said, it helps to understand how electronic products are designed in the first place.

The design process starts with a written specification stating how the product works, the calculations and decisions it has to make, and how it interacts with the user. Next, a hardware design engineer determines the circuit elements needed to perform the desired functions -- keyboards or sensors for input, displays or actuators for output, and memory for the program and calculation variables -- and develops schematic diagrams showing how these devices connect to the microprocessor, the central brain.

Then a software designer writes the source code, a program to read the relevant inputs, perform the necessary calculations and drive the corresponding outputs. Such a a control program, Wharton said, may consist of anywhere from 2,000 to 20,000 individual statements combined to form hundreds of individual subroutines, or subprograms.

A master detective who traces the evolution of high-tech designs.


At this point, the source code consists of instructions in an abbreviated English-like form that people can read and modify.

But before the program can be executed, it has to be translated into a combination of bits (ones and zeros) understandable to the microprocessor.

That translation, performed by programs called assemblers, leaves the program in a form incomprehensible to humans. "It's as though one were to flip 100,000 coins and try to make sense of the pattern of heads and tails that result," Wharton said.

This information, many tens of thousands of bits, is loaded into the microprocessor's memory when the system is manufactured and causes the hardware circuitry to perform the functions and calculations for which the product was designed.

In reverse engineering a product, Wharton said, one goes through the same steps in opposite order: The engineer removes the program bits from the chip's memory, uses a disassembler to convert them back into the program source code, analyzes that source code to figure out what the functions were and what they did, and examines the electronic circuitry to understand how various signals are used. The engineer can then produce a lengthy written description of the product's functions, which should be essentially the same as the manufacturer's original specifications.

With many of the patent projects Wharton works on, he said, he seldom hears how a case turns out. Nor does he particularly care to find out.

For Wharton derives much of his satisfaction from the thrill of the puzzle itself, like the inner workings of the Furby. Apart from Dave Hampton, the inventor and engineer who created Furby and whom Wharton reveres, Wharton may understand Furby's innards better than anyone else. Although he and Hampton are acquainted, Wharton would never think to ask Hampton for a road map.

"That would be cheating," he said. "It would be like asking the guy who wrote the crossword puzzle for the answers."

One of Wharton's recent projects for hire involved dissecting a home blood diagnostic instrument. In the middle of the assignment, he took an unexpected trip to Sydney, Australia, so he hauled everything with him, including a bag filled with soldering irons, precision knives, voltmeters, jumper wires, pliers, clippers and screwdrivers, and sat for several evenings in his hotel room in Sydney, taking the system apart and studying its circuitry.

"One of the things that's curious about this work is that it requires time and isolation, being away from distraction," he said.

When not in the thick of a technical project, Wharton appears to be easily distracted. A lover of movies, he is a regular at film festivals, and he has invested in a small film. He had a bit part in the recent movie "Ed-TV." He has also witnessed each solar eclipse visible from North America since 1991, flying off to Mazatlan or Aruba at a moment's notice.

Wharton has also been known to apply his reverse engineering skills to other parts of his life, with impressive results.

In 1996, when the Letterman show came to San Francisco, Wharton made a calculated effort to get noticed. He figured out which seats the camera would be most likely to focus on and made sure that he was seated there.

He made himself conspicuous by undoing his ponytail and letting his hair down and donning a tie-dyed shirt. He ended up looking "just like the sort of San Francisco hippie" the show's producers would expect to see, he said.

It worked. Letterman himself strode into the audience, asked Wharton his name, then asked if he would agree to take a shower in the host's dressing room -- an ongoing gag of Letterman's. Wharton happily obliged. The cameras followed Wharton, from his torso up, as he disrobed, stepped into the shower and lathered up. On his way back into the audience, clad in a white bathrobe, he managed to snatch a copy of the script.

Those who knew Wharton well were not at all surprised by the triumph. Wharton was later immortalized on Internet discussion groups as "the Shower Guy" and was even paid union scale for his appearance.

In fact, Wharton said, he was paid at the rate for a speaking part because he said two words on the air, "John" and "sure."

In a similarly well-plotted effort in 1984, Wharton won a Porsche in a product design contest after he figured out that the sponsor, a chip manufacturer, would most likely reward the entry that best suited its marketing efforts, not necessarily the best design.

Reverse engineering, Wharton said, is not unlike cryptography in that it involves breaking codes. But cryptography no longer interests him. "There are now algorithms in place that cannot be broken," he said. "If you're looking for difficult problems, you have to look elsewhere, and reverse engineering is the closest I've found so far."




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