The global personal computer industry is set to undergo its biggest sea-change since Microsoft's introduction of Windows as a bolt-on to MS-DOS in November 1985.

In those pre-Ordovician days, the display of graphics on anything other than room-sized computers was the preserve of whacko creatives doing arcane visual things on Apple machines in back rooms. For ordinary mortals, WYSIWYG on a DOS-driven dinosaur was a distant dream!

Since when the world has spun a few turns and Apple, now relegated to the role of runner-up to world-conquering Windows, has struck back.

Steve Jobs' troops have just beta-released Boot Camp, software that enables users to run the Windows XP operating system on Macs built with Intel processors - a recent and highly significant development.

Thanks to the new Intel chips, Mac owners can run XP in tandem with Apple's OSX operating system. Although the beta version of Boot Camp requires users to perform a separate instal of the XP software, it walks them through the installation process.

Thereafter, when a Mac loaded with both systems is switched on, Boot Camp gives users the option to start either OSX or Windows XP. In the latter mode, it can run any program written for Windows.

Future versions of OSX will contain a built-in version of Windows XP, although Apple insists it has no plans to sell or support its rival's operating system.

So what's in it for Apple? "We think Boot Camp makes the Mac even more appealing to Windows users considering making the switch," says Philip Schiller, Apple's svp of worldwide product marketing.

Microsoft, of course, clearly stands to gain from the additional XP licensing income; but the news is likely to spark an outbreak of nervous tics among branded PC manufacturers such as Dell and Hewlett-Packard.

Data sourced from BBC Online; additional content by WARC staff