Windows 10 Roadmap

What was already an open secret has now been confirmed (apparently accidentally) by one of Microsoft's partners in the PC supply chain. Thanks to offhand remarks from AMD's president and CEO Lisa Su, we now know that Microsoft is planning to launch Windows 10 at the end of July.

But what will actually happen when the appointed date rolls around? That poses some interesting logistical questions for Microsoft.

The Windows 10 upgrade program is going to be one of the largest software delivery projects in history. Microsoft is offering full, free upgrades for every PC currently running Windows 7 or Windows 8.1 Service Pack 1 (excluding those running Enterprise editions, which don't qualify for the free upgrade).

That means a 2GB+ upgrade package downloaded to each PC.

So just how big is the eligible Windows 10 upgrade base? It is certainly measured in the hundreds of millions, representing PCs running Windows in dozens of languages, all over the world.

Apple's been doing this for a few years with OS X, but on a much smaller scale, measured in the low tens of millions for each new release. Microsoft's upgrade program for Windows 8.1 was probably larger than that but still only a small fraction of the worldwide PC installed base.

There's actually a road map hidden in plain sight, included with a recent optional update for Windows 7 and Windows 8.1. An XML file installed with that update contains important clues about a program called GWX: Get Windows 10.

KB3035583 describes itself innocuously enough: "This update enables additional capabilities for Windows Update notifications when new updates are available to the user. It applies to a computer that is running Windows 8.1 or Windows 7 Service Pack 1 (SP1)."

That's it. No, seriously, that's the entire description. But the KB article does go on to describe the files included with this update, most of them containing the acronym GWX.