Windows-Only Games
Many years ago, Sun Microsystems designed a system named Wabi, which allowed Windows 3.1 executables to run unmodified on the Solaris operating system. Not to be outdone, the open-source crowd decided to get in on the action, beginning the WINE (WINE Is Not an Emulator) project in 1993. The differences deep down between Linux (and other Unixes) and Windows are huge, and running applications made for Windows is no simple task - especially with Microsoft constantly shifting the goalposts. However, the WINE project has continued for twelve years now, improving constantly. WINE can now, quite happily, run applications for Windows ranging from Internet Explorer to Photoshop.
Microsoft Internet Explorer 6 looks right at home on my Linux desktop via WINE
That said, WINE has to fight against billions of Windows applications all using and abusing the Windows specifications in their own subtle ways. In recent times, however, the obvious desire for Windows applications on Linux has caused some large companies (such as Macromedia) to begin modifying their products to minimise the number of non-WINE-friendly commands they use - it costs them very little, and can help them sell a few more copies!
As time went by, two commercial, paid versions of WINE appeared, with very focused goals rather than the fairly broad 'run anything' goals of the main WINE project. Codeweavers Crossover Office, designed to run the latest in 'big' Windows applications (Microsoft Office being the big one), and TransGaming WineX, designed to play Windows games. WineX was later renamed Cedega.
Half Life (the Steam version) runs happily under Cedega
As commercial versions, there is money involved with both Crossover and Cedega - The standard edition of Crossover Office costs $39.95. Cedega is sold on a subscription basis, whereby one month of access to the download servers costs £3 - with anything you download being yours to keep. There is also a public CVS server for Cedega, with a limited version of the source code available - this is often hard to get to do anything useful, and lacks many features, and is usually not worth worrying about for the sake of £3.
