Saturday, Nov. 20, is the 25th anniversary of the Windows operating system. The first release was aptly named Windows 1 while the latest is Windows 7, but in between, Windows naming schemes were very inconsistent.
The first two releases of Windows were only available to buyers of IBM, Compaq and a few other computer brands. The general public would not be able to pick up a copy of Windows until the release of Windows 3. Those first three versions were odd in that they were not actually operating systems they were operating environments meaning the Windows interface rode on top of the true underlying operating system called Disk Operating System (DOS).
During the Windows 3 period, Microsoft split the line-up between consumers and businesses with the release of the NT line. Windows NT was unique in that it did not run on top of DOS; it was a true preemptive multi-tasking operating system that operated in protected mode resulting in more stable operation. The last numbered version was NT4.
For the next few years, Microsoft abandoned straight version numbers in favor of release year numbers giving us the 9X consumer series that included Windows 95, 98 and the simply awful Windows Millennium. The business series went from NT4 to Windows 2000.
After Y2K, Microsoft changed course again by merging the separate consumer and business lines and they stopped using a naming scheme with numbers in favor of straight names. The next Windows release would be XP, which enjoyed the longest run of all previous Windows versions, followed by Vista.
Today with Windows 7, we're right back where we started from with straight version numbers. Initial reporting on the next version say Microsoft will call it Windows 8? I'll believe it when I see it.