Windows 2.0

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Template:Infobox OS Windows 2.x is a family of Microsoft Windows graphical user interface-based operating environments that succeeded Windows 1.0. Windows 2.x was said to look similar to the original Mac OS and more closely matched Microsoft's pre-release publicity for Windows 1.0.

1 Windows 2.0
2 Windows 2.1x
- 2.1 Windows/286
- 2.2 Windows/386
3 See also
4 External links

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Windows 2.0

Released on November 1 1987, Windows 2.0 allowed for windows to overlap each other, in contrast to Windows 1.0, which could only display tiled windows (this limitation was artificially imposed due to lawsuits from Apple Computer; dialogs and drop-down menus were in fact overlapping windows in Windows 1.0). This version also introduced the window-manipulation terminology of "Minimize" and "Maximize", as opposed to "Iconize" and "Zoom" in Windows 1.0, and a more sophisticated keyboard-shortcut mechanism in which shortcut keys were identified by underlining the character that, in conjunction with the "Alt" key, would cause them to be selected. File management tasks were still managed by use of the MS-DOS Executive program, which was more list-driven than icon-oriented.

The first Windows versions of Microsoft Word and Microsoft Excel ran on Windows 2.0. Third-party developer support for Windows increased substantially with this version (some shipping the Windows Runtime software with their applications, for customers who had not purchased the full version of Windows). However, most developers still maintained DOS versions of their applications, as Windows users were still a distinct minority of their market.

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Windows 2.1x

Less than a year later, Windows/286 2.1 and Windows/386 2.1 were released on May 27 1988. These versions could take advantage of the specific features of the Intel 80286 and Intel 80386 processors.

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Windows/286

Windows/286 took advantage of the HMA to increase the memory available to Windows programs. It introduced the himem.sys DOS driver for this purpose. It also included support for several EMS boards for this same purpose (this support was not related to the 80286 processor per-se). The segmented nature of Windows programs was quite suited to the usage of EMS, as portions of code and data could be made visible in the first megabyte of memory accessible to real-mode programs only when the program using them was given control. Microsoft encouraged users to configure their computers with only 256KB of main memory, leaving the address space from 256-640KB available for dynamic mapping of EMS memory.

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Windows/386

Windows/386 was much more innovative. It introduced a protected mode kernel, above which the GUI and applications were running as a virtual 8086 mode task. It allowed several MS-DOS programs to run in parallel in virtual machines, rather than always suspending background applications. (Windows applications could already run in parallel through cooperative multitasking.) Each DOS application could use as much low memory as was available before Windows was started, minus a few kilobytes of overhead. Windows also provided EMS emulation, using the memory management features of the processor to make RAM beyond 640K behave like the banked memory previously only supplied by add-in cards and used by popular DOS applications. (By overwriting the WIN200.BIN file with command.com, it was possible to use the EMS emulation in DOS without starting the Windows GUI.) There was no disk-based virtual memory, so multiple DOS programs had to fit inside the available physical memory; Microsoft suggested buying additional memory (and cards) if necessary.

Neither of these versions worked with DOS memory managers like CEMM or QEMM or with DOS extenders, which had their own extended memory management and ran in protected mode as well. This has been remedied in version 3.0 which was compatible with VCPI in "standard mode" and with DPMI in "386 enhanced" mode.

The various Windows 2.x versions were superseded by Windows 3.0 in May 1990.

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External links

GUIdebook: Windows 2.0 Gallery - A website dedicated to preserving and showcasing Graphical User Interfaces

**History of Microsoft Windows**
MS-DOS–based: 1.0 • 2.0 • 3.0 • 3.1x • 95 • 98 • Me
NT-based: NT 3.1 • NT 3.5 • NT 3.51 • NT 4.0 • 2000 • XP • Server 2003
CE-based: CE 3.0 • Mobile • CE 5.0
Forthcoming: Vista • FLP (thin-client) • Server "Longhorn" • "Fiji" • "Vienna"