Win32s is a 32-bit application runtime environment for the Microsoft Windows 3.11 operating system. It allowed some 32-bit applications to run on the 16-bit operating system using call thunks. 32-bit is a term applied to processors, and computer architectures which manipulate the address and data in 32-bit chunks. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ... This article or section does not adequately cite its references or sources. ... // An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. ... In computer science, 16-bit is an adjective used to describe integers that are at most two bytes wide, or to describe CPU architectures based on registers, address buses, or data buses of that size. ... The term thunk is a contrived word from computer science, and has no known root. ...

Concept and Characteristics

Win32s was intended as an implementation of a subset of Win32, Microsoft's main 32-bit Windows API taken from Windows NT 3.1. However, several program compilation options and DLLs which were implicit in Windows NT 3.1 have to be included with the application in Win32s. The Windows API, informally WinAPI, is the name given by Microsoft to the core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. ... The Windows API, informally WinAPI, is the name given by Microsoft to the core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. ... Windows NT 3. ...

Although ostensibly compatible with early versions of Windows NT, many functions were not implemented including threading and asynchronous I/O, newer serial port functions and many GDI extensions. This essentially limits it to applications specifically designed for the platform. In addition, Microsoft made a number of changes to Win32s which were regarded by some observers as an attempt to discourage any third party from marketing a compatible platform^{[citation needed]}. It would not, however, be logical for Microsoft to make developing for Win32s difficult, as it was intended to ease the transition to Win32 for developers and allow Microsoft to shift all of its own development and support to the newer platform. Many programming languages, operating systems, and other software development environments support what are called threads of execution. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... A male DE-9 connector used for a serial port on a PC style computer. ... GDI is short for Graphics Device Interface or Graphical Device Interface, and is one of the three core components or subsystems of Microsoft Windows. ...

At the same time, however, Microsoft already had to manage separate and sometimes incompatible APIs for MS-DOS and Win16, complicating efforts to make a third API (Win32/Win32s) a stable option for developers.

A technique named thunking is fundamental to the implementation of Win32s as well as Chicago-kernel operating systems, which are Windows 95, Windows 98, and Windows Me. However, allowing user-level thunking greatly complicates attempts to provide stable memory management or memory protection on a system-wide basis, as well as core or kernel security—this made it more difficult to write stable programs on Win32s, as well as the Chicago-kernel systems. The stability and security Windows NT can offer is partially based on thunking being totally illegal, except thunks from Win16 to Win32—the CPU must remain in protected mode at all times. Newer versions of Windows transparently provide a virtual machine for running Win16 applications. The term thunk is a contrived word from computer science, and has no known root. ... Windows 95 is a consumer-oriented graphical user interface-based operating system. ... Windows 98 (codenamed Memphis and formerly known as Windows 97) is a graphical operating system released on June 25, 1998 by Microsoft and the successor to Windows 95. ... Windows Millennium Edition, or Windows Me (IPA pronunciation: [miː], [É›m iː]), is a hybrid 16-bit/32-bit graphical operating system released on September 14, 2000 by Microsoft. ... Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ... Protected mode is an operational mode of x86-compatible CPUs of the 80286 series or later. ... In computer science, a virtual machine is software that creates a virtualized environment between the computer platform and its operating system, so that the end user can operate software on an abstract machine. ...

Many early 1990s programs that ran on Windows 3.1 and Windows 95 used Win32s instead of completely separate 16- and 32-bit versions. Several Win32s programs that predate Windows 95 can run on it and often Windows 98. Others were purely Win16, such as Word for Windows. In theory, a "Win32s program" is just a Win32 program that uses only those Win32 calls that are available in Win32s. However, not all Win32 programs are Win32s programs, as many perfectly legal Win32 apps would not initialize at all on Win32s. Microsoft Office Word is Microsofts flagship word processing software. ...

Microsoft dropped support for Win32s from their developer tools with Visual C++ version 4.2 released in late 1996. This article or section does not cite any references or sources. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ...

Sources and installation

Win32s can still be found using web search engines; PW1118.EXE is generally the installation file used. Developers should ensure they are installing OLE if they require consistent clipboard handling. Many applications which need to be made OLE aware (i.e. setting up their OLE server) must be reinstalled. Win32s was also included with some early Win32 programs. Object Linking and Embedding (OLE) is a distributed object system and protocol developed by Microsoft. ...

Trivia

Win32s included an implementation of the card game FreeCell as an example application, years before the game became famous with its inclusion in Windows 95. Part way through game of FreeCell on KDE. FreeCell is a solitaire card game superficially similar to Klondike. ... Windows 95 is a consumer-oriented graphical user interface-based operating system. ...

External links

• Win32 Tutorial by Graeme Chandler
• Win32s Compatibility List
• Download Win32s from Microsoft