Microsoft plans to release six versions of its new Windows 7 operating system, the company announced Tuesday.

Windows 7 screen shot
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The software maker said it will ship Windows 7 Home Premium and Windows 7 Ultimate for the consumer markets. An Enterprise edition will be tailored for large companies, while Windows 7 Professional will be available for general business use. Windows 7 Home Basic will be released only in emerging markets, and Windows Starter Edition will be available for limited types of hardware, according to Microsoft.

"We have a customer base of over 1 billion along with many partners, so it's important to make sure the right edition of Windows with the right features set is available for them," said Mike Ybarra, Microsoft's general manager for Windows, in a statement.

Microsoft is expected to ship Windows 7 in late 2009 or early 2010. The company recommends Windows 7 Home Premium for most consumers, and Windows 7 Professional for home-office workers and small-business employees. Windows 7 Professional contains many of the advanced security features found in Windows 7 Enterprise, Ybarra said.

"For those running Windows Vista Business, it will be a very logical move to Windows 7 Professional," said Ybarra.

Microsoft has designed Windows 7 to be lighter and more resource-efficient than Vista, with an eye to capturing the nascent market for so-called netbook PCs. The netbook category includes low-powered notebooks designed mostly for Web surfing and e-mail use. Vista's inability to fit on netbooks has hurt Microsoft's revenue, with Windows sales down 8% in the most recent quarter.

"At beta we've had a lot of people running our most premium, full-featured offering on the small-notebook PCs with good experiences and good results," said Ybarra.

Microsoft has yet to release pricing details for Windows 7.