Windows 3.1

Windows 3.1 is a series of obsolete 16-bit operating environments produced by Microsoft for use on personal computers, released on April 6, 1992. The series began with Windows 3.1, which was first sold during April 1992 as a successor to Windows 3.0. Subsequent versions were released between 1992 and 1993, notably Windows 3.11, until the series was superseded by the Windows 9x series starting in 1995 with Windows 95. During its lifespan, Windows 3.1 introduced several enhancements to the still MS-DOS-based platform, including improved system stability, expanded support for multimedia, TrueType fonts, and workgroup networking.

Official support for Windows 3.1 ended on December 31, 2001. However, OEM licensing for Windows for Workgroups 3.11 on embedded systems continued to be available until November 1, 2008.

Windows 3.1
Windows 3.1, released on April 6, 1992, introduced a TrueType font system (and a set of highly legible fonts), which effectively made Windows a viable desktop publishing platform for the first time. Similar functionality was available for Windows 3.0 through Adobe Type Manager (ATM) font system from Adobe.

Windows 3.1 was designed to have backward compatibility with older Windows platforms. As with Windows 3.0, version 3.1 had File Manager and Program Manager, but unlike all previous versions, Windows 3.1 cannot run in real mode. It included Minesweeper as a replacement for Reversi (though Reversi was still included in some copies).

Improvements over Windows 3.0
Windows 3.1 dropped real mode support and required a minimum of a 286 PC with 1 MB of RAM to run. The effect of this was to increase system stability over the crash-prone Windows 3.0. Some older features were removed, like CGA graphics support (although Windows 3.0's CGA driver still worked on 3.1) and compatibility with real-mode Windows 2.x applications. Windows 3.1 can run in Standard mode if installed with the VGA display driver. When installed with high resolution/high color driver, it only operates in 386 Enhanced Mode.

Truetype font support was added, providing scalable fonts to Windows applications, without having to resort to using a third-party font technology such as Adobe Type Manager. Windows 3.1 included the following fonts: Arial, Courier New, and Times New Roman, in regular, bold, italic, and bold-italic versions, as well as Symbol (a collection of scalable symbols). Truetype fonts could be scaled to any size and rotated, depending on the calling application.

In 386 Enhanced Mode, windowed DOS applications gained the ability for users to manipulate menus and other objects in the program using the Windows mouse pointer, provided that a DOS application supported mice. A few DOS applications, such as late releases of Microsoft Word, could access Windows Clipboard. Windows' own drivers could not work directly with DOS applications; hardware such as mice required a DOS driver to be loaded before starting Windows.

Icons could be dragged and dropped for the first time, in addition to having a more detailed appearance. A file could be dragged onto the Print Manager icon and the file would be printed by the current printer, assuming it was associated with an application capable of printing, such as a word processor. Alternatively, the file could be dragged out of File Manager and dropped onto an application icon or window for processing.

While Windows 3.0 was limited to 16 MB maximum memory, Windows 3.1 can access a theoretical 4 GB in 386 Enhanced Mode. The actual practical ceiling is 256 MB. However, no single process can use more than 16 MB. File Manager was significantly improved over Windows 3.0. Multimedia support was enhanced over what was available in Windows 3.0 with Multimedia Extensions and available to all Windows 3.1 users.

Windows 3.1 was available via 720 KB, 1.2 MB, and 1.44 MB floppy distributions. It was also the first version of Windows to be distributed on CD-ROM[citation needed] – although this was more common for Windows for Workgroups 3.11, which typically came with MS-DOS 6.22 on one CD[citation needed]. Installed size on the hard disk was between 10 MB and 15 MB.

32-bit disk access (386 Enhanced Mode only) brought improved performance by using a 32-bit protected mode driver instead of the 16-bit BIOS functions (which necessitate Windows temporarily dropping out of protected mode).

Windows 3.1's calendar uses the .cal filename extension.

Windows 3.1 also introduced the Windows Registry, a centralized database that can store configuration information and settings for various operating systems components and applications.

Windows 3.1 was the first version that could also launch Windows programs via Command.com.