At the start of this week Microsoft revealed that for the next iteration of the Windows client, the codename, product number and official label would be one and the same: Windows 7.
At the same time, Mike Nash, corporate vice president, Windows Product Management, indicated that the Windows 7 moniker would have no impact over the actual version of the Windows code. In this context, Windows 7 turns out not to be Windows 7 at all, but actually Windows 6.1, the successor of Windows Vista which is v6.0. Steven Sinofsky, senior vice president, Windows and Windows Live Engineering Group, explained that Microsoft meant for Windows 7 to be Windows 6.1.
"As we started Windows 7 we chose to keep the major version number at 6 so as to maximize compatibility for third party developers. This is really about our commitment to compatibility. And as you have seen with past releases, the major/minor nomenclature for the qualitative aspects of the release don’t necessarily line up with the numeric designations. What you’re seeing with Windows 7 is just a deliberate focus on compatibility over version number vanity (just as you saw with the “major” release of Windows XP)," Sinofsky stated.
The head of the Windows 7 project explained that Windows 7 needed to be Windows 6.1 because of all the software solutions, with an emphasis on setup programs, were tailored to a specific Windows version. In this context, an application or a driver that is hard coded for Windows Vista will fail miserably to install or run under Windows 7, if the operating system features version 7 for its code. Not the same is valid for Windows 6.1. Essentially, all software packages that support Windows Vista will automatically support Windows 7 (Windows 6.1).
"Many folks have done the math to explain why we chose the name Windows 7 – this is because Vista is version "6" of the Windows product line (Windows 1, 2, 3 on 16 bits, Windows 95 was version 4, then Windows 2000 was 5, XP was 5.1, Vista was 6). So we chose "7". (This doesn’t count 98, 98 SE, Me, and of course NT 3.1/3.51 but they all fit in)," Sinofsky added.