Since Windows 7 was announced there's been far too much bellyaching about the name. "It's not the seventh version," people have mumbled on forums and blog comments. Superficially, it's confusing, because the last version was called Vista, and the version before that XP. Apple, on the other hand, is considered to be way above making such elementary naming mistakes, but as we'll discover, it too has a dark past...
Understanding Microsoft's naming isn't always easy though. For a start, you've got the DOS-based OSs such as Windows 95 and ME and the NT-based ones, like Windows 2000 and Vista. Like Vista, Windows 7 is the latest version of NT but it's a consumer-focused operating system, which means it has a userbase that's shared with the older DOS versions of Windows.
NT, which stands for New Technologies, was intended mainly for corporate environments where stability was crucial. DOS-based Windows was never really up to the task, from a stability and security point of view. NT made itself stable by refusing programs direct access to hardware, which meant it wasn't possible for one program to bring the whole OS to its knees. With XP, and to a lesser extent Windows 2000, Microsoft harmonised these operating systems to have the stability of NT but the flexibility of the more consumer-focused, DOS-based systems. For example, you couldn't really play games on NT4, but Windows 2000 and XP both made significant advances in this area.
That's enough history: why call this the seventh version of the OS? We think the most plausible reason for using Windows 7 is to do with consumer familiarity. If we assume Windows 3.x is the first proper version of Windows you'd find in home use, then as it was followed by 95, 98, ME, XP and Vista, we have a compelling reason for the latest to be called 7. It's the seventh version of the consumer OS, even though its heritage is as confused as a sausage dog/Labrador cross-breed.
Under this system, Vista is numbered as Windows version 6. Although Windows 7 shares much of its codebase with Vista, for marketing reasons it's a full and new release. Sadly, no one told that to the engineers working on Windows 7, because its official version number is 6.1, meaning Microsoft doesn't view it as a radical reversioning, but more of a point update. This argument could have been nipped in the bud if that memo had only reached the engineering department in time. To be fair, Apple has been playing this naming game for some considerable time too.
For example, OS X has gone through a number of major revisions, but it's still called OS Ten. system software release 2.0.1 was actually version 4 of the OS.is a point release, taking the OS X to 10.6. Apple understands that giving a product a new name helps it to sell, so it always gives each point release a new name -- a lovable big cat. In fact, if you look at the version history for Mac OS, you'll find there have been many more than 10 versions in total and the naming is even more stupid than Microsoft's. Indeed,
You could also argue Microsoft is hoping to get some harmony across its mobile and desktop platforms. With Windows Mobile 7 due within the life of Windows 7, it seems to make sense to keep the branding the same. From here on in, mobile and desktop versions could be closely tied to each other -- something supported by Microsoft 'Windows Mobile' to 'Windows Phones'.
However you look at it, Windows 7 is a good name for marketing purposes, it has some basis in historical fact and sounds better than calling it something like Windows Wonderful or Windows XLNT.