Windows 2.x

Windows 2.x is the second major version of Microsoft Windows. It was the first version to introduce support for enhanced features found in Intel's i386 processors. To differentiate it between the 8086-compatible version of Windows 2.x, the i386 version was sold and marketed separately under the "Windows/386" label. Two revisions of Windows 2.x exist, the original revision (2.0x) in generic "Windows" (8086/i286) and "Windows/386" variants, and a second revision (2.1x) marketed as "Windows/286" and "Windows/386" respectively. It was the successor to Windows 1.0 and was succeeded by Windows 3.0.

Currently, no pre-release builds of Windows 2.x are publicly available (though some have been confirmed to exist), and some retail versions remain unverified.

Development
Windows 2.0 was planned since at least April of 1985, and started development shortly after the completion of Windows 1.01, initially as a point release, version 1.1. One of the primary complaints from those who used Windows 1.0x (which sold over 500,000 copies and was a modest success, contrary to what is claimed in popular media) was the design of tiled windows, which many users found confusing. To solve this, an overlapping window scheme was introduced. This was initially optional (and could be configured in Control Panel), but it was later decided to kill the tiled window scheme entirely and move to exclusively overlapping windows. By October 1986, the product had been renamed to Windows 1.5, and then again shortly after that to version 2.0, most likely as a recognition of the large changes that had been made (many new APIs had been added and parts of the kernel had been rewritten from C into assembly or vice versa). The product, in traditional Microsoft fashion and like almost every other version of Windows before and after, missed its initial release date of early 1987; other than that the development appears to have been fairly orderly with no large hiccups (unlike its predecessor), and two alpha releases were sent to developers around May or June 1987, followed by two beta releases in July and August 1987.

At the same time as Windows 2.0, Microsoft were also working on a version of Windows designed to use the Intel 386's virtual 8086 mode to pre-emptively multitask MS-DOS (or, in Microsoft parlance, old) applications in virtual machines. This product was completed first, possibly due to contractual obligations, and version 2.01 was released with Compaq DeskPro 386 machines in September 1987. After two months of further bugfixes and polishing, the "main" (808x-only) version was released on December 7, 1987 as version 2.03. The product was reviewed quite positively as a large improvement from its predecessor, with Windows/386 specifically singled out for praise, with the product winning a BYTE Award for "technical distinction" in January 1989. Over a million copies were sold by 1988, and although sales dropped somewhat in 1989 they still generally met internal sales targets (per antitrust documents) and nearly two million copies had been sold by January 1990. An increasing number of Windows applications were produced during this period, including the final completion of Word for Windows after a multi-year (starting in August 1984, around the same time as Windows 1.0 DR4), tortured development cycle in which the product missed over a dozen release dates and fell behind several Windows versions, and Excel for Windows.

New features
Windows 2.0 introduced support for overlapping windows for all window variants, while Windows 1.0 only supported overlapping of dialog windows. This fired a legal conflict with Apple Inc., accusing Microsoft and Hewlett-Packard of violating copyrights Apple held on Macintosh System Software. The judge ruled in favor of Microsoft and HP in all but ten of the 189 patents Apple sued for, which according to the judge couldn't be copyrighted.

This version of Windows also introduced support for VGA (Video Graphics Array) displays and PS/2 mice in the retail release, although drivers for Windows 1.0 have already been available in IBM's OEM release. It is possible to use the PS/2 mouse driver from Windows 2.03 with Windows 1.0, which enables one to use the virtual mouse emulated by many virtualization packages.

Windows/386
Windows/386 is a variant of Windows 2 optimized for the 386 processor. It took advantage of the virtual 8086 mode to preemptively multitask MS-DOS applications, however, Windows itself still uses cooperative multitasking. Each MS-DOS instance is running in a separate virtual machine on top of a 32-bit virtual machine manager, which allows for better compatibility as they no longer share memory space with the rest of the environment. A bigger range of applications can also run in a window as opposed to the original variant, due to Windows/386 introducing grabber files that allow for better video emulation.

A modified version of Windows is running in the so-called System VM, a special virtual machine that controls the VMM and has access to all I/O devices by default. Both Windows and MS-DOS applications could also make use of EMS emulation provided by the virtual machine manager. However, swap is not supported and all running applications therefore have to fit into physical memory.

The original version was renamed to Windows/286 starting with version 2.1 (which added the ability to use the High Memory Area or HMA for an additional 64KB of conventional memory), although it does not necessarily require a 286 processor and still runs on the original 8086 and 8088. The separate 386 variant was discontinued with Windows 3.0, which includes its functionality in the 386 Enhanced mode. The new Standard mode also carries over some of the MS-DOS support improvements, such as grabber files.

Control Panel myth
Contrary to popular belief, this version is not the first to include the Control Panel, a claim which at one point also appeared on Microsoft's own website. The Control Panel was already included with Windows 1.0 Development Release 5, compiled over 3 years before Windows 2.0 was released.

Easter egg
All retail versions of Windows 2.x include an Easter egg, which shows a scrolling list of people that were involved with the development of Windows alongside a "Congrats!" button. Double-clicking the list box also changes the background of the Easter egg window to tiled smiley faces. This Easter egg is very similar to the one in Windows 1.0. To trigger this Easter egg, you must press F1, F5, F9, F4, and Backspace in quick succession.