Win32s

Win32s is a

Win32s was intended as a partial implementation of the Win32 Windows API as it existed in early versions of Windows NT.^[3]

The "s" in Win32s signifies subset, as Win32s lacked a number of Windows NT functions, including multi-threading, asynchronous I/O, newer serial port functions and many GDI extensions. This generally limited it to "Win32s applications" which were specifically designed for the Win32s platform,^[4] although some standard Win32 programs would work correctly, including Microsoft's 3D Pinball Space Cadet and some of Windows 95's included applets.^[5] Early versions of Internet Explorer (up to Version 5) were also Win32s compatible, although these also existed in 16-bit format.^[5] Generally, for a 32-bit application to be compatible with Win32s, it had to not use more than 16MB of memory or any extended features such as DirectX.

Win32s inherits many of the limitations of the Win16 environment. True Win32 applications execute within a private virtual address space, whereas Windows 3.x used an address space shared among all running applications. An application running on Win32s has the shared address space and cooperative multitasking characteristics of Windows 3.1. Consequently, for a Win32 application to run on Win32s, it must contain relocation information.

A technique named

Win32s included an implementation of the card game FreeCell as an example application, a couple of years before the game became famous with its inclusion in Windows 95.

Warcraft II: Tides of Darkness, a DOS game, included a level editor that required Win32s to run. The editor used a Windows GUI for displaying the large maps because high-resolution graphic modes were already handled by Windows. The NCSA Mosaic web browser version 2 also required Win32s.^[6]

$ sha512sum pw1118.exe
31b532f324a1eebd1073e043e0c81cb131ad40681b1a7e5e73f881369eafa38ba9d91a541d99fd8b96e937f0e93bfd17cf9c26cc77daf8c77d7c9df803b3aef9

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.

References