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The Windows Story

Abstract

Windows began as a late, slow graphical shell over MS-DOS. Microsoft announced it on 10 November 1983 and shipped version 1.0 two years later, on 20 November 1985, for $99. It took until Windows 3.0 in 1990 to sell in large numbers, and Windows 95 turned an operating-system launch into a $300 million media event. Under the consumer line Microsoft built a second, unrelated system, Dave Cutler’s Windows NT, which replaced the DOS lineage with Windows XP in 2001. XP stayed in service far longer than Microsoft planned: support ended in 2014, Microsoft still patched it during the WannaCry outbreak of 2017, and in 2026 an XP-era Windows desktop was photographed on a London railway platform display. Its dominance brought antitrust cases in the United States and Europe, its ambition produced the collapse of the “Longhorn” project, and its slow response to the smartphone produced Windows 8. Since Windows 10 (2015) Microsoft has treated Windows as one business among several, while the system remains on roughly seven in ten desktop computers. In July 2024 a faulty security update from CrowdStrike crashed 8.5 million Windows machines and showed how much of the world’s infrastructure still runs on it.

Microsoft Building 92
Building 92 on Microsoft’s Redmond campus. Image: Coolcaesar, CC BY-SA 4.0, via Wikimedia Commons.

Interface Manager

By 1983 Microsoft’s main product was MS-DOS, the text-based operating system of the IBM PC (see Bill Gates and Microsoft). Graphical interfaces from Xerox PARC were reaching personal computers. At the autumn COMDEX in Las Vegas in November 1982, Bill Gates watched VisiCorp demonstrate Visi On, a windowing environment for the IBM PC that showed several programs on screen at once and was driven with a mouse. VisiCorp was the publisher of VisiCalc, the program that had sold the Apple II to businesses, and Gates ordered a comparable product of Microsoft’s own. Apple’s Lisa followed in January 1983, and Microsoft was writing applications for the coming Macintosh, so the company saw both rivals from close up.

In August 1983 Gates hired Scott McGregor, who had worked on the windowing system at Xerox PARC, to lead the project. Its working name was Interface Manager. Rowland Hanson of Microsoft’s marketing department proposed calling it Windows instead, after the one thing every user would see on the screen.

The Announcement

On 10 November 1983 Microsoft presented Windows to the trade press in New York. Accounts differ on whether the event took place at the Helmsley Palace or at the Plaza. Representatives of 23 computer companies attended and pledged to offer Windows on their machines. IBM, whose PC the rest of the industry was copying, stayed away and was preparing its own text-based multitasking shell, TopView. The announcement came less than two weeks after VisiCorp had begun shipping Visi On. Microsoft promised to deliver to dealers in April 1984; John Markoff’s report in InfoWorld recorded the company’s own caveat that “a product like Windows is difficult to predict and may take longer.”

Byte previewed the software in its December 1983 issue under the headline “A mouse with modest requirements.” The Lisa and an IBM PC XT running Visi On both needed a hard disk and large amounts of memory. Windows was to run from two 320-kilobyte floppy disks in 192 kilobytes of RAM, as an installable device driver under MS-DOS 2.0, and Microsoft promised to price it “as an operating-system component”, which Byte translated as “inexpensively.” Programmers would need neither Unix nor special hardware to write for it, only an ordinary IBM PC. The magazine’s photographs showed overlapping windows; a note added to the caption reported that Microsoft had since adopted “tiling”, in which the running programs always divide the whole screen among themselves. A page of photographs showed Windows on machines from other makers, among them the Compaq Portable, the Zenith Z-100, and the professional computers of Texas Instruments and Wang.

Three weeks after the press event Microsoft demonstrated Windows applications at the autumn COMDEX in Las Vegas, where Dan Bricklin filmed the first video of the software. In Germany Der Spiegel quoted Microsoft’s description of Windows as a “Meilenstein in der Software-Entwicklung”, a milestone in software development.

Two Years Late

April 1984 passed, then May. In November 1983, the month of the announcement, the newsletter writer Esther Dyson had popularized a word for software that is announced long before it works: vaporware. By late 1984 the computer press was writing about a “War of the Windows” between Microsoft’s product, IBM’s TopView, and Digital Research’s GEM, and none of the three had shipped yet. Critics read Microsoft’s early announcement as a way to keep customers from buying rival products while they waited.

Inside Microsoft the project had a reputation, in the words of Tandy Trower, “for career death.” Four product managers had tried and failed to ship it. Trower, who had managed Microsoft BASIC and the company’s other programming languages, was offered the job by Steve Ballmer late in 1984, after Rob Glaser had turned it down. Trower suspected that the offer was a polite way of firing him, put the theory to Gates and Ballmer, who laughed, and moved to Windows in January 1985. McGregor resigned at about the same time and Ballmer took over development himself. Ballmer had just finished a tour of apologies to analysts and the press for the delay, and he gave the team six months. He fixed the minimum machine as a standard IBM PC with 256 kilobytes of memory, two 5¼-inch floppy drives and no hard disk, and a CGA graphics card. There was no time left to replace the fixed-width system font with a proportional one, which made Windows look crude next to the Macintosh, shipped in January 1984.

Windows also had no applications. The developers had written a few samples (Notepad, a calculator, the game Reversi, and the start of Paint), and Trower proposed finishing them as a bundle so that buyers would have something to do with Windows, adding Write, a small word processor based on Microsoft Word. Ray Ozzie, then working for Lotus, gave feedback that shaped the keyboard interface, and Gabe Newell, later the founder of Valve, was among the people who tested it. A “Premiere Edition” went to software vendors, analysts, and the press in early summer 1985, in partial fulfilment of Ballmer’s promise of a summer release, and a redesign of the memory management forced the testers to start again.

Windows 1.0

Windows 1.0, strictly version 1.01, went on sale on 20 November 1985 for $99. Microsoft celebrated at the autumn COMDEX in Las Vegas, at the Alexis Park hotel, with a roast of itself hosted by the columnist John C. Dvorak, and Stewart Alsop of InfoWorld presented Gates with a “Golden Vaporware” award for the delay. Ballmer recorded a mock television commercial in which he sold Windows in the manner of a late-night used-car dealer.

The product ran on top of MS-DOS, and its windows were tiled side by side rather than overlapping. Microsoft had signed an agreement with Apple in November 1985 licensing certain visual elements of the Macintosh interface for Windows 1.0. Reviewers found the product slow, it needed more memory than most PCs had, and there were few applications beyond the ones in the box. Version 1.02, aimed at the European market, followed in May 1986 with the first versions in languages other than English. Computerworld counted about 500,000 copies sold between the launch and April 1987, a small number next to the installed base of MS-DOS. Microsoft kept supporting Windows 1.0 until 31 December 2001, the longest support period of any Windows version.

Windows 2.0, released on 9 December 1987, allowed overlapping windows again, a change Trower pushed through, and a separate edition, Windows/386, used the protected mode of Intel’s 80386 to run several DOS programs at once. Microsoft’s own Excel and Word for Windows gave people a reason to install it.

On 17 March 1988 Apple sued Microsoft and Hewlett-Packard, claiming that Windows 2.03 and HP’s NewWave infringed the copyrights in the Macintosh’s visual displays. The case lasted six years. Judge William Schwarzer dismissed most of Apple’s 189 claims, finding that the bulk of the similarities were either covered by the 1985 license or were basic ideas that copyright could not protect, and on 19 September 1994 the Ninth Circuit affirmed: infringement could exist only if the two interfaces as a whole were “virtually identical”. The ruling meant that the general ideas of a graphical interface (windows, icons, menus, a pointer) could not be owned through copyright.

Windows 3.0

Windows 3.0, released on 22 May 1990, was the first version to succeed. Microsoft launched it at the New York City Center before about 6,000 guests, with video links to other cities, at a cost of $3 million; Gates called it the “most extravagant, extensive, and expensive software introduction ever.” The full version cost $149. Windows 3.0 used the protected-mode memory of the 286 and 386 processors, so programs could use several megabytes of memory instead of DOS’s 640 kilobytes; it had a redesigned interface with the Program Manager and File Manager; and it ran acceptably on the cheap 386 PCs then flooding the market. It sold about 10 million copies in the two years before Windows 3.1, released to manufacturing on 6 April 1992, replaced it. Version 3.1 added TrueType scalable fonts, and Windows for Workgroups (3.1 in 1992, 3.11 in 1993) added built-in networking for offices.

Windows 3.0 also shipped with Solitaire, written by a summer intern, Wes Cherry, in 1988, with a card deck designed by the former Macintosh artist Susan Kare. Microsoft included it to make the system less intimidating and to get people used to the mouse: moving a card is a drag-and-drop operation. Windows 3.1 replaced the old Reversi game with Minesweeper, which Curt Johnson had written for OS/2 and Robert Donner ported to Windows, and which had first appeared in the Microsoft Entertainment Pack of 1990. In 2019 the Strong National Museum of Play inducted Solitaire into its World Video Game Hall of Fame.

For most people in the early 1990s, Windows 3.x on an IBM-compatible PC was their first graphical computer. Its success also ended Microsoft’s partnership with IBM on the next-generation operating system OS/2. Microsoft put its effort into Windows and left IBM with the technically more advanced system that lost the market (see Dead End: OS/2).

Windows 95

Microsoft’s next consumer release, code-named Chicago, became Windows 95, released on 24 August 1995. It replaced the Program Manager with the Start button and the taskbar, introduced long file names and Plug and Play hardware detection, and ran 32-bit programs, though it still rested on DOS underneath for compatibility with old software and drivers.

The launch was a public event of a kind no software had had before. Microsoft spent up to $300 million on promotion. It licensed the Rolling Stones’ “Start Me Up” for its advertising (Microsoft’s chief operating officer Bob Herbold later put the fee at about $3 million, well below the figures reported in the press); the comedian Jay Leno appeared with Bill Gates at the launch in Redmond; stores opened at midnight; and the Empire State Building was lit in the Windows colors. About one million copies sold at retail in the first four days.

The startup sound came from the musician Brian Eno. The brief from Microsoft’s agency asked for music that was “inspiring, universal, blah-blah, da-da-da, optimistic, futuristic, sentimental, emotional,” and ended: “and it must be 3 1/4 seconds long.” Eno told the San Francisco Chronicle in 1996 that he made 84 pieces before delivering one: “It’s like making a tiny little jewel.”

Windows 95 also had to run nearly every program written for DOS and Windows 3.x, including programs that broke the rules. Joel Spolsky, who heard the story from one of SimCity’s developers, described what the Windows team found when the game kept crashing in testing: SimCity used memory immediately after freeing it, which happened to work under DOS. The Windows developers disassembled the game, found the bug, and added code that put the memory allocator into a special mode, in which a program could keep using memory after freeing it, whenever SimCity was running. Such special cases for individual programs accumulated with every release. They are the reason old software kept running on new Windows versions, and the reason those versions were hard to clean up.

Windows 98 (June 1998) and Windows Me (September 2000) continued the DOS-based line; Me, the last of it, was widely regarded as unstable.

Windows NT

Dave Cutler
Dave Cutler, who led the design of Windows NT after building VMS at DEC, receiving the National Medal of Technology and Innovation. Image: Ryan K Morris / National Science & Technology Medals Foundation, public domain, via Wikimedia Commons.

While the consumer line carried DOS forward, Microsoft built a second operating system from scratch. In 1988 it hired Dave Cutler, the architect of the VMS operating system at Digital Equipment Corporation, with several of his engineers. Their system, Windows NT (New Technology), was fully 32-bit, ran each program in protected memory so that one crash could not bring down the machine, was designed to be portable across processors (it ran on MIPS, Alpha and PowerPC as well as Intel), and was built for security and networking from the start. Its story is told in Dave Cutler and Windows NT and in G. Pascal Zachary’s book Showstopper!

Windows NT 3.1 shipped in 1993, numbered to match the consumer Windows, and was sold for workstations and servers. NT 4.0 (August 1996) took the Windows 95 interface, and Windows 2000 (February 2000) became the standard for corporate desktops and servers. NT needed more memory than home PCs had in the mid-1990s; within a few years the hardware caught up.

Windows XP

Windows XP, code-named Whistler, merged the two lines: the NT kernel under the consumer brand. It was released to manufacturing on 24 August 2001 as build 2600 and went on sale on 25 October 2001, in Home and Professional editions. Microsoft held the launch in New York six weeks after the September 11 attacks, at the Marriott Marquis in Times Square, with Mayor Rudy Giuliani welcoming the guests and a free Sting concert in Bryant Park afterwards. On stage Gates typed “exit” at a DOS prompt “for the last time.”

XP introduced the Luna look, with a green Start button and, as the default desktop, a photograph of a green hill under a blue sky. The former National Geographic photographer Charles O’Rear had taken it in January 1996 in southern Sonoma County, California, on a hillside cleared of vines after a phylloxera infestation, with a Mamiya RZ67 medium-format camera on Fujifilm Velvia film. He sold it through a stock agency as Bucolic Green Hills. Microsoft bought the full rights through Corbis in 2000 and renamed it Bliss. O’Rear is bound by a confidentiality agreement about the price; courier services refused to carry the original transparency because its value exceeded their insurance, so Microsoft flew him to Seattle to deliver it by hand. O’Rear later estimated from XP’s sales that it had appeared on about a billion computers, and called the number “an educated guess.”

XP was also the first Windows to require product activation: an installation stopped working after 30 days unless it was activated with Microsoft, and a large hardware change could void it.

Its security record in the first years was poor. On 11 August 2003 the Blaster worm began spreading through a flaw in the DCOM RPC service of Windows 2000 and XP that Microsoft had patched a month earlier (bulletin MS03-026). It needed no user action; infected machines rebooted themselves after a 60-second countdown, and the worm’s code contained the message “billy gates why do you make this possible ? Stop making money and fix your software!!” About 423,000 systems were infected by 15 August. Jeffrey Lee Parson, an 18-year-old from Minnesota who wrote the B variant, was sentenced to 18 months in prison in 2005. Microsoft rebuilt much of XP’s security for Service Pack 2, released on 25 August 2004, which switched on the Windows Firewall by default and added the Security Center, part of the Trustworthy Computing effort described in Secure by Design.

Because Vista sold poorly, XP remained the most-used desktop system in the world for years after its successor appeared. Net Applications measured Windows 7 overtaking it only in August 2012, by 42.76 to 42.52 percent. Mainstream support ended on 14 April 2009 and extended support on 8 April 2014, when many ATMs, hospitals and government offices were still running it. Embedded variants lasted longer: support for Windows Embedded POSReady 2009, used in shop tills, ran until 9 April 2019. When the WannaCry ransomware spread on 12 May 2017 (see The Ransomware Epidemic), Microsoft took what it called “the highly unusual step” of publishing a security update for Windows XP, Windows 8 and Windows Server 2003, all out of support.

At its 25th anniversary in 2026, StatCounter still counted XP on 0.09 percent of Windows desktops, more than Windows 8 at 0.02 percent, and machines that never touch the web do not appear in those figures. In June 2026 a reader of The Register photographed a platform information screen at Limehouse station on London’s driverless Docklands Light Railway showing an application error over a Windows desktop of the XP era; the reader suggested it might also be Windows Server 2003.

Antitrust

Microsoft’s control of the PC operating system brought the largest antitrust case of its era. After Microsoft bundled Internet Explorer with Windows and pressured PC makers and internet providers to favor it over Netscape (see The Browser Wars), the US Department of Justice and twenty states sued on 18 May 1998. Judge Thomas Penfield Jackson found on 5 November 1999 that Microsoft held monopoly power, and in June 2000 he ordered the company split in two, separating Windows from the rest. On 28 June 2001 the appeals court in Washington upheld the finding that Microsoft had illegally maintained its monopoly but reversed the breakup, citing the judge’s comments about the company to reporters. Microsoft and the Justice Department settled in November 2001 with conduct remedies, which Judge Colleen Kollar-Kotelly approved in 2002.

Europe followed. In March 2004 the European Commission fined Microsoft €497 million for abusing its dominant position, by bundling Windows Media Player and by withholding interoperability information from rival server makers, and required a version of Windows without the media player, sold as Windows XP N.

A second case concerned Internet Explorer. To settle it, Microsoft committed on 16 December 2009 to show European Windows users a browser choice screen listing rival browsers in random order; it went live in March 2010. Windows 7 Service Pack 1, however, shipped without it, and from May 2011 until July 2012 about 15 million users in the EU did not see the screen. On 6 March 2013 the Commission fined Microsoft €561 million, the first fine it had ever imposed for breaking a commitments decision. The obligation expired in December 2014. The broader story is in The Platform Antitrust Story.

Longhorn and Vista

After XP, Microsoft set out to build its most ambitious release. “Longhorn” was to include a new graphics system, a new programming model based on managed .NET code, and WinFS, a file system built on a relational database that would let users search and relate their documents, mail and contacts. The parts did not fit together, and the code base became unstable. In August 2004 Microsoft restarted development from the Windows Server 2003 code and announced that WinFS would not be in the release.

The result, Windows Vista, reached businesses on 30 November 2006 and consumers on 30 January 2007. It was late, demanding of hardware and incompatible with many drivers, and its User Account Control prompts annoyed users constantly. A “Vista Capable” sticker campaign on PCs that could barely run it led to a class-action lawsuit, and the internal e-mails produced in court in February 2008 showed that Microsoft’s own managers had been caught by it. The vice president Mike Nash wrote: “I PERSONALLY got burnt… I now have a $2,100 e-mail machine.”

Apple used the moment. Its “Get a Mac” television campaign (2006 to 2009) set the actor Justin Long, as a relaxed Mac, beside the writer John Hodgman as a stiff PC in a suit, and many of the spots joked about Vista’s problems. Microsoft answered in late 2008 with “I’m a PC,” opening with a Microsoft employee, Sean Siler, who resembled Hodgman.

Vista’s security architecture survived, however, and Windows 7, released on 22 October 2009, was largely Vista refined and was received as the version Vista should have been.

Two other Windows-era misfires are covered separately: the cartoon assistants of Microsoft Bob and Clippy, and the word processor Windows helped displace in WordPerfect.

Windows 8

Sinofsky LarsonGreen BUILD 2011
Steven Sinofsky and Julie Larson-Green presenting Windows 8 at Microsoft’s BUILD conference in September 2011. Image: BUILDWindows, CC BY 2.0, via Wikimedia Commons.

The iPhone (2007), Android and the iPad (2010) moved personal computing to touchscreens that Windows did not run on. Microsoft’s answer, led by the Windows chief Steven Sinofsky, was Windows 8, released on 26 October 2012. It replaced the Start menu with a full-screen Start screen of tiles in the “Metro” style, designed for fingers, and added a store for touch apps, while the old desktop remained underneath. A version for ARM tablets, Windows RT, could run only store apps. Mouse-and-keyboard users disliked the new interface, and tablet buyers stayed with the iPad and Android. Sinofsky left Microsoft weeks after the launch, and Windows 8.1 (2013) restored a Start button. Microsoft’s phone effort failed at the same time (Dead End: Microsoft’s Mobile Failures).

Windows 10 and 11

Under Satya Nadella, chief executive from 2014, Microsoft stopped treating Windows as the center of the company; the Azure cloud and Office 365 subscriptions became its growth businesses. Windows 10, released on 29 July 2015, was a free upgrade for users of Windows 7 and 8 for its first year, restored the Start menu and was delivered as “Windows as a service”, with major updates twice a year. A Microsoft developer evangelist, Jerry Nixon, called it “the last version of Windows”. In March 2020 Microsoft reported one billion monthly active Windows 10 devices.

Microsoft pushed the free upgrade hard. Windows 7 and 8 machines showed recurring upgrade prompts, and many users who clicked “close” on one of them found that they had agreed to the upgrade. Teri Goldstein, who ran a travel agency in Sausalito, California, sued in small-claims court after an upgrade she had not asked for left her Windows 7 PC unusable for days; she won $10,000, and Microsoft dropped its appeal in May 2016 to avoid further legal costs. “Nobody ever asked me if I wanted to update,” she said.

Microsoft also made concessions that would once have been unthinkable. The Windows Subsystem for Linux (2016) let developers run Linux programs inside Windows, and in 2020 the Edge browser moved to Google’s open-source Chromium engine, ending Microsoft’s own browser engine.

Windows 11, released on 5 October 2021, broke Nixon’s promise. It required a recent processor and a TPM 2.0 security chip, which left many working PCs unable to upgrade; Microsoft called the requirement “non-negotiable”. Support for Windows 10 ended on 14 October 2025, with paid Extended Security Updates for businesses available until October 2028. In May 2024 Microsoft announced Recall, a feature for its new “Copilot+” AI PCs that took screenshots every few seconds so that users could search everything they had seen. Security researchers showed that the first version stored its data unencrypted; Microsoft delayed the feature, rebuilt it as opt-in with its data in an isolated enclave, and released it in April 2025. In January 2024 Microsoft also announced a Copilot key for new PC keyboards, which its marketing chief Yusuf Mehdi called “the first significant change to the Windows PC keyboard in nearly three decades,” that is, since the Windows key.

The Blue Screen

The blue screen of death first appeared as a true crash screen in Windows NT 3.1 in 1993. Its stop-error screen began with *** STOP: and was written by the NT developer John Vert, who used white text on blue in his own programming setup. In Windows 3.1 a blue text screen appeared when a user pressed Ctrl+Alt+Del to deal with a hung program, and in Windows 95 a blue screen reported serious errors; Raymond Chen, who maintained its code, added the driver name and memory offset to the message, by his own account “to make my own life easier.”

Myth: Steve Ballmer wrote the blue screen of death

In September 2014 Raymond Chen wrote that Steve Ballmer, then head of the Systems Division, had rewritten the text of the Windows 3.1 Ctrl+Alt+Del screen, and the team used his wording almost verbatim. Tech news sites turned this into “Ballmer wrote the blue screen of death.” Chen corrected them a week later: the Ctrl+Alt+Del screen appeared only when a user pressed the keys, and it was not the crash screen. Ballmer wrote some text; the NT crash screen came from John Vert and the Windows 95 one passed through Chen’s hands. See Myths and Misconceptions.

The most public blue screen came at the Spring COMDEX show in Chicago on 20 April 1998. During Bill Gates’s keynote, his assistant Chris Capossela plugged a USB scanner into a Windows 98 demonstration PC to show Plug and Play, and the machine crashed. “That must be why we’re not shipping Windows 98 yet,” Gates said. The development team had tested a different scanner in the lab; the demo team had bought this one at a local store. Back in Redmond the engineers found that it reported itself as a low-power bus-powered device and then drew more current than that allowed, triggering an untested error path. Chen reported that the scanner was mounted on a Second World War infantry helmet, which an engineering manager wore to the War Room meetings for the rest of the project. Windows 98 went on sale on 25 June 1998.

Later versions changed the look. Windows 8 added a sad face, “:(”, in 2012, and from 2016 Windows 10 added a QR code linking to troubleshooting help. On 26 June 2025 Microsoft announced that Windows 11 would replace the blue screen with a simpler black one.

The CrowdStrike Outage

CrowdStrike BSOD LGA
Departure screens at LaGuardia Airport, New York, showing Windows crash screens during the CrowdStrike outage of 19 July 2024. Image: Smishra1, CC BY-SA 4.0, via Wikimedia Commons.

On 19 July 2024 the security company CrowdStrike pushed a faulty configuration update to its Falcon sensor, a program that runs inside the Windows kernel to detect attacks. Machines that received it crashed with the “blue screen of death” and could not boot without manual repair. Microsoft estimated that 8.5 million Windows devices were affected, less than one percent of all Windows machines, but they included the computers of airlines, banks, hospitals, broadcasters and emergency services. Flights were grounded around the world, and repairing the machines took days.

The outage was not caused by a Windows bug, but it revealed two things about Windows’s position. Critical infrastructure in much of the world still ran on it, and third-party security software ran with full kernel privileges, an arrangement Microsoft said it could not change on its own because of the 2009 interoperability commitments it had made to the European Commission. Afterwards Microsoft began work on letting security software run outside the kernel.

Dead End

The clearest abandoned bet in Windows history is WinFS. Its idea went back to the early 1990s, when Microsoft’s “Cairo” project promised an object file system in which documents could be searched and related by their contents and properties rather than by folder paths. Cairo never shipped as planned. The idea returned as the centerpiece of Longhorn: WinFS would store files, contacts, e-mail and calendar items in a relational database built on SQL Server technology, so that a user could ask for “all the documents I sent to this person last month.”

WinFS was removed from Longhorn in August 2004 and promised as a later add-on. On 23 June 2006 Quentin Clark announced on the WinFS team blog that it would not ship as a separate product; parts of the technology went into SQL Server and ADO.NET instead. The underlying problem was that a database file system had to be fast, compatible with every existing program that expected ordinary files, and reliable enough to hold all of a user’s data, at once. Desktop search tools that indexed ordinary files, including Microsoft’s own Windows Search, delivered much of the promised benefit without changing the file system. The same pattern runs through Windows’s other dead ends (OS/2, Windows RT, Windows Phone after the $7.2 billion Nokia purchase, and the Internet Explorer engine): the enormous base of existing applications and drivers protected Windows from failed experiments and also made it very hard for Windows to change.

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