According to Bob Dubke, the second engineer on IBM's 5100 team in Rochester

(who now co-owns a locally-based company called eXport Ventures Corp.

and also works for Edina Realty), that secret function was his contribution to the design of the computer.

The function, which IBM suppressed because of worries about how their competition might use it,

was an interface between the assembly code surrounding the computer's ROM exterior,

and the 360 emulator hidden beneath it. (IBM declined to comment for this story.)

The 5100's emulator gave programmers access to the functions of the monstrous,

and much less portable machines, that IBM had produced during the 1960s.

An imprint of a hook on the outside of the 5100 symbolized the ability

of Dubke's interface to drop into what Titor called "legacy code,"

and scoop out any necessary operating instructions.

A hook is an appropriate symbol for Titor's story.

His posts ended in March 2001, after his supposed return to the future.

In the wake of his disappearance,

the claims he'd made about the 5100 became the starting point

from which all manner of Internet kooks conducted searches for proof of his claims.

Unlike his vague predictions of future doom,

the information he'd relayed about the 5100 was concrete,

and filled with statements that readers could research. It's a surprise,

then, that Dubke hadn't heard about the Titor debacle until we contacted him in July.

Period documentation Dubke provided calls the computer a "dramatic step forward,"

and reveals that the 5100 team were justifiably excited about their project's release.

According to Dubke, they'd been set free from bureaucratic controls,

and so had worked smoothly and efficiently on the 5100's design.

The end result was a computer that, though antiquated in comparison to current technology,

was an engineering marvel. Bulky but functional. When Dubke first heard about John Titor,

his main question was not of whether John Titor was a time traveler,

("I'm not a �Star Trek' watcher," he says, "or into building fantasies")

but of who among his team had the right sense of humor

to orchestrate the furor created by Titor's posts.

"Somebody is trying to tickle somebody else," Dubke says.

In response to our inquiries, he mentally reviewed the list of engineers

with whom he'd spent turbulent and fun times at IBM.

One candidate who emerged, a man with a "caustic" sense of humor, seemed to Dubke to be the most likely jokester.

However, as he reviewed Titor's posts, he dismissed them as being "too simple"

to be the product of any of his friends, and his eyes stumbled over the sight of the phrase "legacy code,"

which, he says, no members of the 5100 team would ever use.

He concludes that Titor's 5100 material was merely "derived from information available on the Internet."