Microsoft has lofty ambitions for its next generation Windows Vista operating system as witnessed by statements made by the company in early October. Today, IDC issued some new projections for Windows Vista including the notion that over 90 million units of the operating system will ship in 2007 worldwide. That figure far outpaces Microsoft's assessment of 67 million units in the first year of availability for Windows XP.

"After a long wait, the adoption of Windows Vista will take place almost immediately among consumers, while businesses will follow a decidedly more conservative adoption curve," says Al Gillen, research VP of System Software at IDC.

On the consumer side, Vista Home Basic is expected to garner 67% of Vista purchases while Vista Home Premium will account for 30%. The enthusiast-oriented Vista Ultimate will account for 2% of the product mix with just 1% of consumers choosing Vista Business for use in home deployments.

For businesses, Vista Business will account for 82% of Vista deployments while Vista Enterprise will capture the remaining 18%.

Overall, IDC projects that 90% of new Windows client installations for home users will be comprised of Vista Home Basic/Vista Home Premium during the first year. On the business side, Vista Business/Vista Enterprise will account for just 35% of new client installations during the first year – that number rises to 80% during the second year of availability.

But while consumers buying new PCs will pretty much be forced into using Windows Vista after the start of the year, businesses are likely to be a bit more discriminating. Businesses typically wait until at least the first service pack for a new Windows operating system is released before they do any large roll-outs throughout the company.

Gartner suggests that companies should spend as much as 18 months testing a new operating system before moving to large-scale deployments. With Vista being launched for businesses tomorrow, now is the time to begin the testing phase (if companies haven't already done so with earlier versions of Vista). "If companies do decide to upgrade the biggest barrier will be application compatibility - 80 per cent of your applications will work and 20 per cent won't work. The vast majority of customers we speak to are looking at 2008 to upgrade but they need to start planning now," said Frank Foxall of Windows migration specialist Camwood.