When Rob Steerum of Fulcrum Global Partners asked Tim Cook, Appleis VP of Worldwide Sales and Operations, about the chances of a G5-based PowerBook anytime soon, Mr. Cook admitted Wednesday such a project "would be the mother of all thermal challenges."

When asked if he meant there will never be a G5-powered PowerBook, Mr. Cook said, "I donit want to go further in the comment."

The comments came during Appleis conference call Wednesday discussing its first quarter fiscal earnings with analysts.

Mobile users have already been waiting a year and a half for Apple to pack the processor that powers its pro towers into Appleis pro laptop. It took Apple two years, however, to find a way to take the G4 processor and pack it into portable form.

In September of 2003, Spanish Web site CincoDias quoted Apple CEO Steve Jobs as saying he hoped Apple could release a PowerBook G5 "by the end of [2004]."

Two months later, in November, Dave Russell, director of product marketing for portables and wireless at Apple, told Computerworld that Apple "would like" to fit a G5 into a PowerBook, but that the biggest obstacle was cooling the processor. One only needs to watch how liquid cooling (QuickTime 1.6MB) enables the G5 processor to survive in the aluminum Power Mac tower to realize that packing such a system into a laptop is a daunting task. "We certainly want to [offer a PowerBook G5]," Russell said at the time. "But itis going to be a while. We think the G4 has a very long life in the PowerBook."

In February of 2004, Peter Glaskowsky of the Microprocessor Report told MacMinute that IBMis PowerPC 970FX--the latest iteration of the G5 processor found in todayis high-end Power Mac G5 systems--offers the basic power consumption features needed for a laptop. At the time, Glaskowsky said he believed a PowerBook G5 would debut by the summer. It never did.

In an April 19, 2004 interview with BBC News, Apple VP Greg Joswiak commented that, "In the very long run, the G5 is part of our long term processor roadmap, but it will be some time before that processor will be in a notebook."