Nancy Blair

USA TODAY

SAN FRANCISCO — Microsoft has taken the wraps off Windows 10, the next big version of its iconic operating system.

Consumers and businesses won't get it until 2015. A fter unveiling a sneak peek to the press on Tuesday, Microsoft today is making available a technical preview for IT professionals and other very experienced computer users who apply for the company's Windows Insider program.

Here's what we know now about Windows 10:

IT WILL BE ON ALL SORTS OF DEVICES

Microsoft is talking about a unified version of Windows that will be tailored for a broad spectrum of devices: PCs, of course, and tablets and phones. But also "connected" everyday appliances known as the Internet of Things. And even, eventually, its Xbox gaming console. The idea is that there will be a familiar framework that will be tailored depending on whether you are using Windows on a small screen like a phone or tablet, or on a larger screen computer or even an 80-inch TV.

WHAT WILL BE DIFFERENT FOR ME?

That really depends on what version of Windows you are currently using. Earlier this year, Microsoft ended support for Windows XP. An XP user who has hung on will certainly find a whole new world. For those on Windows 7 or Windows 8, the new Windows 10 promises to be a good blend of the two that pushes the computing experience even further into the modern age of touchscreen and on-the-go mobile access.

START MENU, LIVE TILES

The Start menu is back, along with the familiar taskbar. But now the Start menu will include a customizable space for apps you like and Windows Live Tiles (apps that give you at-a-glance info -- new messages say, or the latest update from a friend on Facebook).

There will be one Windows Store for apps for tablets, phones, PCs and more.

It will be easier to work in multiple apps at once. There's a new "quadrant" layout that allows up to four apps at once to be snapped onto the same screen.

Microsoft also demonstrated an easier way for people who use 2-in-1 tablet/laptop devices to switch back and forth between laptop and tablet modes. It's called "Continuum."

WHY MICROSOFT IS SO FOCUSED ON BUSINESS USERS RIGHT NOW

Companies have shied away from Windows 8 in droves. The early rap was that it was just too different from Windows 7, and too focused on touchscreen experiences. Microsoft needs to get companies on board with Windows 10 early, and it believes that opening up the development experience will help it do that. And in the past couple of years, more and more 2-in-1 laptop/tablet devices have hit the market, which means more people are becoming familiar with touchscreen ways of getting work tasks done.

WHAT ISWINDOWS INSIDER AGAIN?

Microsoft is opening up a technical preview of Windows 10 for those who are interested in testing it and providing feedback to the company as it continues to work on the new OS. This is not a program aimed at typical consumers but at IT professionals and experienced computer enthusiasts. You can find out more at the preview site preview.windows.com. (In other words: Don't try this at home.)

Follow Nancy Blair on Twitter: @nansanfran.

MORE TECH NEWS AT USA TODAY: