MacWindows:
Solutions for integrating Macintosh and Windows.
http://www.macwindows.com/
Clone OS to Run Windows Apps:
An Australian developer is building software that runs Windows NT
applications but doesn't require software from Microsoft.
http://www.wired.com/news/news/technology/story/20637.html
Flopper:
A bootable-disk emulator - it reads a diskette image file (a file
that contains all the sectors of a floppy disk) and boots it. This
way, you can boot (and run) a bootable diskette off of your hard
drive.
http://www.oldskool.org/pc/flopper/
DOSEMU:
An emulator of the Microsoft Disk Operating System (MS-DOS) for
Linux/X11. Enables Linux to run many DOS programs - including some
DPMI applications.
http://www.dosemu.org/
TWIN API:
Software tools and services enabling Windows applications to run on
UNIX, Macintosh and other Systems.
http://www.willows.com/
WABI:
WABI is a Windows 3.1 emulator for Linux.
http://solarflow.dyndns.org/wabi
Eliel Software Development:
Software for developers and game players, featuring DodGE: the DOS
Game Emulator for Windows.
http://www.eliel.com
DOSBox:
An open source DOS emulator for BeOS, Linux, and Windows. Primarily
focuses on running DOS Games.
http://dosbox.sourceforge.net/
