Steve Wozniak, who co-founded Apple with the late Steve Jobs, predicted "horrible problems" in the coming years as cloud-based computing takes hold.
Wozniak, 61, was the star turn at the penultimate performance in Washington of "The Agony and the Ecstasy of Steve Jobs," monologist Mike Daisey's controversial two-hour expose of Apple's labor conditions in China.
In a post-performance dialogue with Daisey and audience members, Wozniak held forth on topics as varied as public education (he once did a stint as a school teacher) and reality TV (having appeared on "Dancing with the Stars").
But the engineering wizard behind the progenitor of today's personal computer, the Apple II, was most outspoken on the shift away from hard disks towards uploading data into remote servers, known as cloud computing.
"I really worry about everything going to the cloud," he said. "I think it's going to be horrendous. I think there are going to be a lot of horrible problems in the next five years."
He added: "With the cloud, you don't own anything. You already signed it away" through the legalistic terms of service with a cloud provider that computer users must agree to.
"I want to feel that I own things," Wozniak said. "A lot of people feel, 'Oh, everything is really on my computer,' but I say the more we transfer everything onto the web, onto the cloud, the less we're going to have control over it."
Prior to Saturday at the Woolly Mammoth theater in Washington, Daisey and Wozniak had met once before, in California after a performance of "The Agony and the Ecstasy" in its original version in February 2011.
Wozniak was moved to tears, but a year later Daisey came under fire when it emerged that sections of his one-man show dealing with the Foxconn plant in China where iPhones and iPads are assembled had been fabricated.
Public radio show "This American Life," which had broadcast portions of "The Agony and the Ecstasy," went so far as to issue a retraction. Daisey meanwhile reworked his script, albeit without toning down his powerful delivery.
On the minimalist stage Saturday, seated on plain wooden chairs, Daisey and Wozniak came across as a geek version of Tweedledum and Tweedledee in their baggy black clothes and matching beer bellies.
The bearded, fast-talking Wozniak sported running shoes and a massive wrist watch. In the theater lobby, for Saturday only, one of the very first Apple I computers ever built -- assembled in Jobs' garage -- was on display.
"Everything I designed was purely out of my head, never out of a book," recalled Wozniak, who quit Apple in 1987 after 12 years, taught fifth-graders, hit the lecture circuit and gave away some of his fortune to good causes.
Many in the audience echoed Daisey's concern about Foxconn's work force, but Wozniak said he expected labor conditions in China to evolve as the nation grows richer. He also commended Apple for its oversight of its factories.
"We know we (citizens and consumers) have a voice. We can speak (about labor conditions), but we can't act like, oh, Foxconn is bad or Apple is bad," he said.
Daisey begged to differ: "I hear what you're saying about that fact that everyone goes through an evolution, but it's not as if the evolution was natural in the sense that we are the ones who brought the jobs there."
While Apple designs its products in the United States, all its manufacturing takes place in China -- a sore point in an election year in which unemployment and a long-term exodus of manufacturing jobs overseas have been campaign issues.