Windows 7 equals some strange math

In many ways, Microsoft's decision to keep the Windows 7 name was entirely logical.

It was the product's code name, something relatively simple, and it is generally seen as a lucky number (at least here in the United States).

But to arrive at the number 7, Microsoft does some strange math, as general manager Mike Nash outlined in a blog posting Tuesday. Nash writes:

The very first release of Windows was Windows 1.0, the second was Windows 2.0, the third Windows 3.0.

Here's where things get a little more complicated. Following Windows 3.0 was Windows NT, which was code-versioned as Windows 3.1. Then came Windows 95, which was code-versioned as Windows 4.0. Then, Windows 98, 98 SE and Windows Millennium each shipped as 4.0.1998, 4.10.2222, and 4.90.3000, respectively. So we're counting all 9x versions as being 4.0.

Windows 2000 code was 5.0, and then we shipped Windows XP as 5.1. Even though it was a major release, we didn't want to change code version numbers to maximize application compatibility. That brings us to Windows Vista, which is 6.0. So we see Windows 7 as our next logical significant release and seventh in the family of Windows releases.

Well, there you have it.

Perhaps more noteworthy is the fact that, although Vista got the version number 6.0, Windows 7 won't actually be version 7.0. Rather, it will be Windows 6.1.

That goes to the very fine line Microsoft is trying to walk with Windows 7. The company is at once trying to reassure IT folks that it is not a radical departure from Windows Vista and at the same time tell consumers it is a significant upgrade from Vista.

In his blog post, Nash tries to thread that very fine needle as well.

"We learned a lot about using 5.1 for XP and how that helped developers with version checking for API compatibility," Nash wrote. "We also had the lesson reinforced when we applied the version number in the Windows Vista code as Windows 6.0 -- that changing basic version numbers can cause application compatibility issues. So we decided to ship the Windows 7 code as Windows 6.1, which is what you will see in the actual version of the product, in cmd.exe or computer properties."

But he tries to convince consumers that they shouldn't read too much into that decision. "There's been some fodder about whether using 6.1 in the code is an indicator of the relevance of Windows 7," Nash wrote. "It is not."

Of course, the real proof will come in two weeks, when Microsoft hands out the first Windows 7 code to developers and outlines what the operating system update is all about. Then we will all be able to better judge for ourselves just how big a deal Windows 7 is (or isn't).