After five years absence, Apple co-founder Steve 'Woz' Wozniak joined a special panel discussion looking at Mac OS X following Apple CEO Steve Jobs' keynote speech at Macworld Expo.

He discussed the division between Mac users running Apple's new and old operating systems.

Presently, many use OS X, but find themselves stranded in the world of OS 9 when they want to run older applications and hardware, such as falling DTP standard QuarkXPress. Other essential software also remains unwritten - some hardware-device drivers, such as scanners, are missing.

This makes the transition tough for some users, Wozniak said. "You have to eventually make the transition," he said.

Old and new "I use OS X, but I have computers with OS 9 doing important tasks. Why would I switch when it just works forever?" Wozniak said, noting that his home-computer collection includes a number of desktop and notebook machines running various versions of Apple's operating system.

"The expense of upgrading system software hurts a lot of people," Wozniak added.

US graphics professional Miles Kaplan explained: "I use OS 9 for some older Adobe software I haven't paid hundreds of dollars to upgrade yet."

Application crashes Application instability has also deterred migration, Wozniak alleged, saying: "I would urge a lot more applications testing before release."

Despite his criticisms, Wozniak praised OS X for its Unix roots. He said: "I think Unix is great because it opens up the OS to a ton of computer science students," Wozniak said. "I use it for a few simple network tasks, and I'm glad it's there."

The Unix component plays its most important role when it comes to making Apple a member of the enterprise-computing world, he said.

"The real credibility of OS X applies to business IT departments, and even to high-level networks," he said. "It will fulfill enterprise computing needs much more than OS 9."

Wozniak also suggested that new Mac users are best served by choosing Mac OS X for their first machine, because it is the platform that Apple will best support going forward.

On a related note, he said OS X will offer a far better experience to new users than did earlier operating systems.

"There was a point in time when the Mac crashed an awful lot more than Windows machines," he said.