What happened to Windows 9?
Why "Windows 10"? Windows 9 was the "natural" name for this release, Terry Myerson said, and was indeed the original name. But after joking about a few fake names—like Windows One—he noted that this isn't an incremental release. It's a major new Windows that will run on everything from headless Internet of Things devices to phones to tablets to PCs to the Xbox to the cloud. They really wanted to segregate it from current Windows versions.
From blogger Paul Thurrott...
At the risk of sounding stupid, what does " headless Internet of Things devices"
even mean? I've never heard that before.
Windows embedded such as smart devices like TV's, appliances, car audio (Ford Sync),etc... that really do not have a "UI" in the traditional sense.
Windows 10??? WTF???
Microsoft skipped 9 like Nvidia did with 800 series.