Win4Lin
Win4Lin is a software application for Linux which allows a user to run a copy of Microsoft Windows 95, 98, Me, 2000 or XP applications on their desktop. The system works by acting in a similar way to a virtual machine, in that it provides an environment for the Windows operating system to run, and as such one must still have a copy of Windows to use with it.
The Win4Lin application in essence displays a window on a Linux desktop which contains the Windows desktop environment. As an alternative, the Windows environment can be run full screen, outside of the desktop environment to save on desktop real estate.
Win4Lin is designed with business users in mind, and as such, does not support features such as MIDI, in favor of support for Microsoft Office-style application compatibility.
Win4Lin was based on Merge which was originally developed for running DOS/Windows 3.1 on SCO Unix. Merge was devised by Gerald Popek and developed by his firm Locus, later taken over by a company called Platinum. The Merge technology was then bought by a company called DASCOM which was in turn bought by IBM. A company called TreLOS was then spun off that continued the development of the virtual machine software and created Win4Lin. TreLOS and LastFoot.com merged in 2000 to form NeTraverse, Inc.
In early 2005 the assets of NeTraverse were purchased to form Win4Lin Inc. which introduced Win4Lin Pro Desktop - this is based on a 'tuned ' version of qemu, and kqemu and it hosts NT-versions of Windows. In June 2006, Win4Lin released Win4Lin Virtual Desktop Server based on the same code base. Win4Lin Virtual Desktop Server serves Microsoft Windows sessions to thin clients from a Linux server.
Win4Lin Pro and Virtual Desktop Server use "full" virtualization, whereas Win4Lin 9x was an example of paravirtualization.