History of Microsoft Windows: From MS-DOS to Windows 11

A graphical environment, not an operating system

Bill Gates announced the “Windows” name in November 1983, but the product didn’t reach store shelves until two years later, on November 20, 1985. The delay was long enough that, as Microsoft engineer Chris Pratley later recalled, “Windows development started back in 1983, and it was a joke in the industry … Betting the company on it was a big, big bet.” When it finally shipped, Windows 1.0 was not a complete, self-contained operating system: it was an “operating environment,” a 16-bit graphical shell that ran on top of MS-DOS, bundled with programs like Paint, Write, Notepad, Calendar and the game Reversi. Its windows, on top of that, could only be tiled across the screen, not overlapped the way later Windows interfaces would allow. It saw little popularity.

Later versions slowly improved things. Windows 2.0, released on December 9, 1987, saw somewhat wider adoption than its predecessor, helped along by the availability of the Aldus PageMaker desktop publishing software, and added support for the High Memory Area on Intel 80286 processors. The real turning point came with Windows 3.0 in May 1990: it was the first to run Windows programs in protected mode with virtual memory support, worked across a range of processors from the 8086/8088 up to the 80386, and sold around 10 million copies within two years, the platform’s first genuine mass commercial success. Windows 3.1 (April 1992) added scalable TrueType fonts, developed jointly with Apple, and dropped the old real mode, requiring at least an 80286 processor: by that point, the Windows API had become the de facto standard for consumer software, a role that a language like PHP would later come to play on the server side of the web.

A second, more ambitious project running in parallel

While Windows was growing as a graphical shell on top of MS-DOS, Microsoft was about to start an entirely different kind of project. In October 1988, work began on a new operating system led by Dave Cutler, an engineer who had joined the company that same month, on October 31, from Digital Equipment Corporation. There, starting in April 1975, Cutler had already designed the VMS operating system, and two years later, in 1977, he watched the first VAX roll off DEC’s production line. Gordon Bell, who had worked alongside Cutler in those years, called him “the best writer of operating systems in the world,” adding: “Dave is the ultimate competitor. He really wants to win.”

The new project — the one that would become Windows NT — aimed at something far more ambitious than a graphical shell on top of DOS: a kernel portable across multiple hardware architectures (MIPS, DEC Alpha, PowerPC, as well as the Intel i860), with a layered architecture split between “user mode” and “kernel mode,” compatible with POSIX, OS/2 and 32-bit Windows APIs, built to meet security certification requirements and capable of taking advantage of multiple processors at once. The first six months were spent purely on specification work; actual coding began in April 1989. Windows NT 3.1 shipped on July 27, 1993, aimed initially not at consumers but at the workstation, office and server markets. Years later, discussing Cutler’s contribution, then-CEO Steve Ballmer would say: “There wouldn’t be a Microsoft today without Dave.”

Real-world example: picture two PCs bought around the same time, say 2000: one running Windows 98, the other Windows 2000. They’re the same age, but internally they’re two different operating systems. The first still carries MS-DOS inside it, with the old memory-addressing limits DOS had dragged along for decades; the second runs on the NT kernel (internally, version NT 5.0), with the NTFS file system extended to consumers and without the old 4 GB per-file limit. Opening the “About Windows” window was enough to tell which of the two worlds you were in.

Windows 95 and the decade of a PC in every home

On August 24, 1995 (after manufacturing had finished on July 14), Windows 95 hit store shelves, backed by one of the biggest marketing campaigns the computer industry had ever seen: Microsoft’s own advertising spend is estimated at around 200 million dollars, while the total campaign, spanning the whole industry, from PC makers to retailers to publishers, is estimated at close to a billion dollars; a promotional video starring Jennifer Aniston and Matthew Perry; the Empire State Building lit up in the blue of the Windows logo; and, most famously, the rights to the Rolling Stones’ “Start Me Up” as the soundtrack for the Start button — Microsoft said it paid 3 million dollars, though contemporary reports put the figure anywhere between 8 and 14 million. Even the system’s startup sound had a well-known name behind it: it was composed by Brian Eno.

Behind the spectacle were real technical advances: 32-bit preemptive multitasking (though the kernel still retained some 16-bit code for compatibility with existing software), the Start menu and taskbar with its notification area, plug-and-play support for automatically installing hardware, file names up to 255 characters long, and Windows Explorer as the file manager. The public responded: a million copies shipped in the first four days, 7 million copies sold in the first five weeks according to Microsoft, and eventually a 57.4% share of the desktop market by the end of 1998, according to International Data Corporation. Windows 98 (June 25, 1998) and its 1999 Second Edition, often remembered as the most stable release in the Windows 9x family, brought a larger-capacity FAT32 file system and improved USB support. Windows Me, on September 14, 2000, closed out the line on a controversial note: conceived as a one-year bridge between Windows 98 and the upcoming Windows XP, it was the last version of Windows built on DOS, it introduced the System Restore feature, but its stability problems earned it the ironic nickname “Mistake Edition.”

Version	Release year	Main innovation
Windows 1.0	1985	First graphical environment on top of MS-DOS
Windows 3.0	1990	First mass commercial success
Windows NT 3.1	1993	NT kernel for workstations and servers
Windows 95	1995	Start menu, taskbar, plug and play
Windows XP	2001	Merger of the NT and consumer lines
Windows 10	2015	Continuous updates, Start menu restored
Windows 11	2021	Redesigned interface, end of 32-bit support

Two lines become one: from XP to Windows 7

While the 9x family was winding down, the NT line kept moving forward on its own: Windows 2000 (NT 5.0, February 17, 2000) brought the Active Directory directory service and extended NTFS support to non-business users, and it saw solid adoption in both the server and workstation markets. On October 25, 2001, the two paths finally merged: Windows XP (NT 5.1) unified the NT/2000 codebase with the consumer 95/98/Me codebase into a single product for the first time, inheriting features like System Restore from Windows Me. Backed by three service packs (2002, 2004 and 2008), XP remained Microsoft’s flagship product for more than five years, one of the company’s longest-lived releases.

Windows Vista (NT 6.0), which reached businesses on November 30, 2006 and consumers on January 30, 2007, introduced User Account Control and the Aero graphical interface, but got a lukewarm reception, criticized mainly for its performance problems. Windows 7 (NT 6.1), available to manufacturers from July 22, 2009 and on sale from October 22, 2009, arrived instead to positive reviews, often described as what Windows 8 “should have been”: it started up faster, handled windows more cleanly, and made User Account Control less intrusive.

The touch era, continuous updates, and modern Windows

Windows 8 (NT 6.2), released on October 26, 2012, tried to reimagine Windows as a touch-first product: the traditional Start menu was replaced by a full-screen Start Screen, with a flat “Modern UI” design in place of Aero and a new app platform called Metro (later renamed UWP). The change was radical enough to draw significant criticism from reviewers, and Windows 8.1 (October 17, 2013) partly reversed course by bringing the Start icon back to the bottom-left corner, to the point that many consider it more of a substantial service pack than a genuine new version.

Windows 10 (NT 10.0), released on July 29, 2015, restored the classic Start menu and introduced a continuous-update model, with 13 major updates rolled out over the years in place of the old, separately numbered versions; it also brought the Cortana virtual assistant and the Microsoft Edge browser, and remained Microsoft’s flagship product for six years, until Windows 11 arrived on October 5, 2021. Windows 11, also built on the NT 10.0 kernel, brought rounded corners and a redesigned Start menu, but it also marks a clean technical break with the platform’s more distant past: it’s the first non-server version of Windows to drop support for 32-bit processors entirely, a compatibility line that stretched literally all the way back to Windows 3.0. Dave Cutler himself, after shipping NT in 1993, kept working at Microsoft on projects spanning much of this history: in 2005 he led the porting of the first 64-bit versions of Windows to the AMD64 architecture, between 2006 and 2008 he worked on the hypervisor underlying Microsoft Azure, and between 2011 and 2013 on the virtual machine inside the Xbox One, in an industry that, as the history of computers also shows, tends to move through successive steps rather than sudden revolutions. Preemptive multitasking, introduced at mass scale by Windows 95 in 1995, is in practice the applied result of an algorithm for managing processes, designed specifically to split computing time between multiple programs without the user ever noticing.