Microsoft is to offer six versions of its next operating system. The different options for Windows 7, released in beta last month,  will be for the benefit of both PC makers and end users, according to a Microoft executive.

"We did a lot of research and talked to a lot of [hardware] partners and customers," said Mike Ybarra, general manager for Windows.

"Our biggest challenge is that we have over 1 billion customers," Ybarra said. "It's hard to satisfy all of them [with a single version]. There are vocal customers who want every feature, and more regular consumers who say 'I want a version that can grow with me.'"

Microsoft said today that it will aim Windows 7 Home Premium at the majority of consumers and Windows 7 Professional at businesses. That harks back to Windows XP , which had two main versions: Home and Professional.

However, Microsoft will maintain all of the four other versions it offered with Vista, a move that caused much confusion. These options will include the controversial Home Basic, the Starter Edition that was until now restricted to developing countries, Enterprise and Ultimate.

In contrast, Apple releases a single version of Mac OS X with every new release. It does have far fewer users than Windows, with some estimates claiming between 30 million to 50 million users worldwide today.

Matt Rosoff, an analyst with the independent firm Directions on Microsoft, said that keeping the number of versions high was all part of Microsoft's attempt to segment the market and "maintain the average-price-per-unit of Windows sales in developed countries to counteract the effects of price pressure in developing countries, where most growth is happening."

Rosoff thinks Microsoft's rejiggered lineup is "simpler" for consumers, but remains too complicated for businesses, who will have to "check the feature list carefully" in order to choose between Professional, Enterprise and Ultimate.

Microsoft did consider cutting Ultimate, a pricey, fully-loaded version that in Windows Vista was aimed at gamers and enthusiasts. "We're keeping it because a lot of top [PC makers] wanted it in order to let them differentiate their own hardware," Ybarra said.

Windows 7 Ultimate won't have any unique multimedia features, but will share the same advanced networking and security features as Windows 7 Enterprise, which is available to large corporations through volume licensing, Ybarra said.

Rosoff expects Ultimate to embraced by businesses rather than enthusiasts, because they will seek to avoid locking themselves into a multi-year license agreement as is required by the Enterprise version.

Rather than cutting Home Basic altogether, Microsoft chose to sell it only in developing markets, where very-cheap PCs are in demand, Ybarra said. "[PC makers] need to hit multiple price points: good, better and best," he said.

Windows 7 Starter Edition is even more limited than Home Basic, allowing users to open only a maximum of three applications at any given time. "We felt that was the right way to go," Ybarra said, as this version will be aimed at new PC users.

While Microsoft is making Windows 7 Starter Edition available for netbooks worldwide, Ybarra expects the majority of PC makers to pre-install Windows 7 Home Premium anyway.

Rosoff agrees, saying that PCs shipped with Windows 7 Home Premium would be likely to cost about US$50(£104) more than those with Starter.

"On a $500 PC, I don't think customers will balk at paying an extra $50 for not having limitations such as the ability to open only three apps simultaneously," Rosoff said. "On a $200 PC (should such a thing ever emerge), that $50 might be a harder sell," said Rosoff.

Ybarra declined to disclose prices for any of the versions. He also declined to say how many 'N' versions of Windows 7, which lack Windows Media Player as per European Union rules, Microsoft will release in Europe.

He promised that users would be able to perform Windows Anytime Upgrades even more quickly with Windows 7 than with Vista. In Vista, users would pay at Microsoft's website to get a licence key and then re-insert their Vista DVD to physically install the upgrade on the hard drive.

With Windows 7, all versions are already installed on the user's PC hard drive, meaning he or she pays and then "simply unlocks the features," Ybarra said. Total upgrade time should be between seven and 10 minutes, he said.

Except for Starter, which will come in 32-bit only, all flavours of Windows 7 will ship in both 32-bit and 64-bit editions, Ybarra said.

He added that Microsoft has no plans to release any more versions of Windows 7 after its initial release, as occurred with XP