Netraverse Win4Lin | Cisco ASA and PIX Firewall Handbook

Netraverse Win4Lin is the third Windows compatibility option covered in this appendix, and it represents a kind of middle ground between the previous two. Like VMware, Win4Lin runs an entire Windows operating system in a virtual computer. Like CrossOver Office, on the other hand, Win4Lin shares your Fedora Core 4 file system instead of using a virtual hard drive. Win4Lin is also a light user of processor and memory resources, like CrossOver Office (and unlike VMware).

You can learn more about or purchase Win4Lin by visiting the Netraverse website at http://www.netraverse.com.

Win4Lin: Architecture and Capabilities

Based on a Windows-on-Unix technology that was originally sold as MERGE for UnixWare, Win4Lin actually does merge, in some ways, Windows and Linux.

Instead of creating a true virtual computer with imaginary hardware, as VMware Workstation does, Win4Lin allows certain versions of Microsoft Windows to run in Linux using a clever trick: Win4Lin replaces the Windows standard drivers for sound cards, graphics hardware, hard drives, and the like, with drivers that interface to Linux's own drivers for the same devices.

This clever architecture allows Win4Lin to avoid the overhead that VMware Workstation incurs in creating imaginary hardware like sound cards and SCSI controllers that are actually compatible with real hardware of the same ilk. On the other hand, it means that Win4Lin is limited to running Windows operating systems; it doesn't support other operating systems such as QNX or FreeBSD, even if they are PC compatible.

In fact, Win4Lin is limited to running just the following versions of Microsoft Windows (and, by extension, applications compatible with them):

Microsoft Windows 95
Microsoft Windows 98
Microsoft Windows Me

Notably absent from this list are versions of Microsoft Windows that are based on Windows NT technology, including Windows NT 3.5, Windows NT 4.0, Windows 2000, and Windows XP. However, the vast majority of Windows applications remain compatible with Windows 95, 98, and Me, and thus function properly in Win4Lin.