Software developers who tried on an Apple Watch for the first time on Friday predicted a rush of new apps over the next few months.
The Apple Watch goes on sale around the world on Friday.
Industry analysts were broadly excited at the prospect, but sceptical that it could produce a working model at a mass-market price that soon.
Microsoft Corp announced its 'Windows 10' operating system on Tuesday to replace the largely unpopular Windows 8, skipping a number to mark a leap toward unifying the way people work on tablets, phones and traditional computers.
Stephen Elop, the former Nokia CEO who now runs Microsoft's devices business, showed off the phone in front of thousands at the company's annual employee meeting in Seattle on Monday.