Windows has a long history.
It's been almost 25 years since Microsoft released the first version of Windows, and more than 15 years since Windows began to dominate the personal computer desktop. Of course, given all the technological changes that have occurred in the past 25 years, today's version of Windows bears only a passing resemblance to Windows 1.0. And that's a good thing.
That first version of Windows was pretty rudimentary. Yes, it was a tad easier on the eyes than the then-reigning DOS operating system, but it wasn't any easier to use. In fact, if you didn't have a mouse—which few users did back in 1985—it was actually harder to use than DOS's type-and-enter command-line interface.
Building on work conducted at Xerox PARC labs and then adapted for the Apple Lisa and Macintosh computers, Windows was a graphical user interface that Microsoft grafted on top of its existing DOS operating system.
It was a good idea, but the first versions of Windows were clunky and didn't have a lot of native applications; for several years, Microsoft Word and Excel were the only two applications that took full advantage of the Windows interface.
Fortunately, Windows got better—and more popular. Microsoft has upgraded Windows on a fairly consistent basis over the past two decades. The company has brought out a new version of Windows every few years or so; sometimes the new version is a minor update, sometime it's a complete overhaul.
For example, Windows 95 (released, unsurprisingly, in 1995) was a total rewrite of the previous 3.X version of Windows. The next version, Windows 98, was a less-significant upgrade, and Windows 98 Second Edition (in 1999) was really no more than a minor bug fix.
So where does the upcoming new Windows 7 fit into this timeline? While Windows Vista, the previous version, was a fairly radical overhaul of the operating system, Win7 is more like Windows 98—an incremental upgrade at best.
That's in keeping with Windows' history, of course, with minor upgrades typically following major ones. Vista was major, Windows 7 is minor, and that's the way it goes.
With that overview in mind, let's take a more detailed look at each successive version of Windows—starting with its most immediate ancestor, the operating system known simply as DOS.
Windows evolved from Microsoft's original DOS operating system, which was released in 1981. This new operating system was developed by Bill Gates and Paul Allen to run the then-new IBM Personal Computer, and utilized a stark text-based interface and simple one-word user commands.
Figure 1 PC-DOS 1.0—Microsoft's original operating system
The way the story goes, IBM contracted with the then-startup Microsoft company to supply the operating system for the initial IBM PC. Gates and Allen purchased the existing QDOS (quick and dirty operating system) from Seattle Computer Products and adapted it as necessary for the new computer system.
The resulting operating system was dubbed DOS, short for disk operating system. DOS was the generic name for what were actually two different operating systems. When packaged with IBM's personal computers, DOS was dubbed PC DOS. When sold in a standalone package by Microsoft, DOS was dubbed MS-DOS. Both versions were functionally identical.
Most first-generation PC users learned to operate their computers using DOS. The operating system was not what one would call user-friendly; it required users to memorize a series of obscure text commands and use those commands to perform most day-to-day operations, such as copying files, changing directories, and so forth. The chief advantage of DOS was its speed and small operating footprint, both important issues when most computers only had 640K memory.