October 1981
PC-DOS 1.0 ships with the new IBM PC. Microsoft ships MS-DOS shortly afterwards and licenses MS-DOS to all comers.

January 1983
Apple releases the Lisa, one of the first microcomputers with a graphical user interface. With unreliable hardware and an average price tag of $10,000, the Lisa is a failure, but it spawns the more affordable Macintosh a year later. The Lisa and the Mac offer what DOS devotees derisively call the WIMP (windows, icons, mice, pointers) interface, as well as folders and long filenames--features that begin to come to Windows with Version 2.0. Some are not fully implemented until Windows 95.

March 1983
MS-DOS 2.0, a substantial rewrite, introduced support for hard disks, larger programs, installable device drivers, and a new, Unix-like hierarchical file system. Still has cryptic eight-character filenames and a text-mode interface.

October 1983
VisiCorp., an offshoot from the company that created the groundbreaking DOS spreadsheet VisiCalc, releases VisiOn, an "integrated environment" that's the first GUI for the PC. It requires 512K of RAM and a hard disk--still a cutting-edge setup at this point.

November 10, 1983
Microsoft announces Windows, an environment that extends the features of DOS with a graphical interface.

September 1984
GEM (Graphics Environment Manager) is announced by Digital Research. Released early in 1985, it can't run DOS apps, which hampers its viability. Both GEM and VisiOn beat Windows to market, but both suffer from same problem as the original Windows: Few applications are available for these new platforms.

February 1985
IBM releases TopView, a text-based DOS multitasker. Only a few DOS commands can be used with TopView. DOS batch files cannot be run by TopView, which intercepts nearly all DOS interrupts. IBM promises to add a GUI to TopView but ultimately never does.

July 1985
Quarterdeck Office Systems releases DESQview, another text-based multitasker for DOS. It succeeds for a time with a limited audience. Quarterdeck makes many attempts to rally developers rally around DESQview as a platform, only to see them fail. Quarterdeck finally gives up after Windows 3.0 becomes the standard.

November 20, 1985
Windows 1.0 ships. Version 1.0 enables users to work with several programs at the same time, switching easily between them without having to quit and restart individual applications. But windows on Windows cannot overlap, crippling usability. Not enough software is written for Windows 1.0, and it fails to take hold in the marketplace.

January 1987
Aldus PageMaker 1.0 ships with a Windows 1.0 "runtime," providing the first WYSIWYG capabilities for publishing on the PC. The popularity of desktop publishing applications, coupled with the release of the laser printer, helps Windows gain entre into desktops.

April 1987
IBM and Microsoft announce OS/2 1.0, the Great Blue Hope of operating systems. Microsoft continues Windows development but hedges its bet on the next-generation PC operating system. OS/2 1.0 doesn't have a GUI, and it finally fails because of a lack of applications and hardware support, poor support for DOS apps, and confusion over whether you need to buy a PS/2 to use it.

October 6, 1987
Excel for Windows 2.0, the first viable GUI spreadsheet for the PC, enters the market to challenge the hegemony of Lotus 1-2-3. Excel helps Windows gain legitimacy, but its high resource requirements and reliance on Windows device drivers make it a pale challenger at this point.

December 9, 1987
Windows 2.0 ships. It uses a system of overlapping windows rather than the tiled windows scheme of previous versions. Can also utilize protected mode on 80286 systems or better, allowing programs to break out of the DOS 640K program size barrier. In June 1988, when Version 2.1 is released, it is renamed Windows 286.

December 9, 1987
Windows 386-- a version of 2.0 optimized for Intel's latest chip--is released. It has some market impact, but mostly, by letting users multitask DOS programs in the 386 chip's "virtual machines," it lays the foundation for much of what emerges in Windows 3.0.

June 1988
Digital Research launches DR-DOS, which the press considers superior to MS-DOS because of its powerful utilities. But DR is distracted from further development by the need to patch its OS to work with Windows, and DR-DOS never garners much market share.

October 31, 1988
IBM's OS/2 1.1 with Presentation Manager ships. The first OS/2 with a GUI, 1.1 is a major upgrade to OS/2 1.0, but it still has insufficient support for popular DOS applications and existing hardware. OS/2's problems encourage Microsoft to continue Windows development and IBM continues to develop OS/2. Sometime later, IBM complains that Microsoft is focusing on Windows, and the two part ways for good.

December 1988
Samna Ami, the first Windows word processor, ships. Users can edit using fonts that resemble print fonts and view margins as they actually appear. WordPerfect remains the dominant word processor, but Ami has much influence, if little impact, on the market. Microsoft Word for Windows will follow soon.

May 22, 1990
Windows 3.0 ships; has significant usability improvements. Program Manager and the icon setup work much better than the old Windows 2 MS-DOS Executive. File Manager is new. Developer enhancements kick-start the Windows software boom. Stability is less than ideal, but Windows 3.0 immediately dominates the market thanks to widespread third-party hardware and software support and preloading by PC vendors. Microsoft's commitment to making Windows work finally pays off.

November 1990
GEOS 1.0, another GUI for DOS, is introduced but never emerges as a true Windows competitor. Although PC Magazine and some other publications laud GEOS's technical merit, no software is available for it. Developer software doesn't ship until six months after the OS.

March 1992
OS/2 2.0 begins shipping. It offers good DOS/Windows 3.x support but is burdened by the complicated Object-Oriented Workplace Shell and by resource requirements that are heavy for the time. OS/2 still lacks widespread driver and third-party software support, and Windows emerges as the market leader.

April 6, 1992
Windows 3.1 is released. It contains numerous bug fixes, is more stable, and adds a few new features, including scalable TrueType fonts. Windows 3.x becomes the operating system most often installed on U.S. PCs and will remain so into 1997.

July 4, 1992
Microsoft announces Win32, the next-generation API for 32-bit Windows NT. The first public mentions of "Chicago" appear (the code name for what will become Windows 95), as well as talk about how the NT product will eventually supplant the existing Windows architecture.

October 27, 1992
Windows for Workgroups 3.1 ships. Integrates networking and workgroup capabilities, including electronic mail delivery, group meeting scheduling, file and printer sharing, and calendar management. Although 3.1 presages the small-LAN boom, it is a commercial failure, earning the ignominious nickname "Windows for Warehouses."

April 1993
With Version 6.0, IBM begins marketing PC-DOS separately from Microsoft. PC-DOS 6.0 incorporates a different memory manager and optimizer from the one Microsoft licensed in the original 1981 IBM PC. Novell acquires DR-DOS and rereleases it, with fancier networking, in December 1993 as Novell DOS 7.0. Both of these efforts are too little, too late, as DOS is waning in significance. All the real PC innovation is happening in Windows and non-Microsoft OSs.

May 24, 1993
Windows NT (which stands for New Technology, although wags refer to it as Not Today, No Thanks, and Nice Try) is launched. Geared towards the power user and the server market from the start, the first version, 3.1, requires a high-end PC to run and is rough around the edges. But Windows NT is well received by developers because of its security, stability, and richer Win32 API, which makes it easier to write powerful programs. The project began as OS/2 3.0 but became a total rewrite of the code.

November 8, 1993
Windows for Workgroups 3.11 ships. Offering improved support for NetWare and Windows NT, it also slips in numerous architectural changes that improve performance and stability and later find their way into Windows 95. Much better received by corporate America this time around.

March 1994
Linux 1.0, a new multiuser Unix operating system that began as a hobby project, is released. Launches the open source code movement wherein any third party can make its own improvements and contribute them to the main product. New hardware and software can be ported to Linux quickly, often before being available for Windows. Although Linux has never had a large commercial presence, it continues to intrigue (even Netscape has mused about integrating Linux and Communicator to take on Windows NT). Indeed, Linux has become the Unix of choice on PC systems, thanks in large part to its popularity with the Linux crowd.

August 24, 1995
After numerous delays and unprecedented prelaunch hype for a software product, Windows 95 ships. In the frenzy, some people line up to buy it even though they don't own a computer. The first Windows version that didn't require the user to install DOS first, Win 95 is the most user-friendly Windows yet and helps spur the mainstreaming of PCs. A much improved interface finally closes the gap with the Mac platform, ultimately marginalizing the Mac further. Win 95 also adds an integrated TCP/IP stack, Dial-Up Networking, and long filename support.

July 31, 1996
Microsoft ships Windows NT 4.0. A much-improved version from 3.51, it features the Windows 95 user interface, expanded device support, and numerous bundled server processes, like its Internet Information Server Web server. NT 4.0 firmly plants Microsoft in the enterprise space. Positioned as a Unix replacement, its presence in corporate America starts small but grows dramatically, and it increasingly becomes the platform for intranets and public Internet sites.

October 1996
OEM Service Release 2 (OSR2) for Windows 95 is made available to manufacturers for preinstallation. Contains interim bug fixes as well as improvements to many of the built-in features and applets of Windows 95 in the control panel. Some of the "new" features in Windows 98 make their debut here, including FAT32, which allows more efficient use of hard disk space, and improved Dial-Up Networking. OSR2 also included Internet Explorer 3.0, the first viable Web browser from Microsoft.

September 23, 1997
First beta of Windows NT 5.0 is given to a developer conference. The massive new version will support new generations of hardware, as well as improved management and security features. Expected release date: 1999.

June 25, 1998
Microsoft launches Windows 98, the last major version of Windows based on the old kernel running on top of DOS. Windows 98 integrates Internet Explorer 4 and supports numerous new device types, from USB to ACPI power management. Future consumer versions of Windows will be built on the NT kernel.