Windows NT 4.0
Windows NT 4.0 Server, Enterprise Edition, released in 1997, is the precursor to the Enterprise line of the Windows server family (Advanced Server in Windows 2000). Enterprise Server was designed for high-demand, high-traffic networks. Windows NT 4.0 Server, Enterprise Edition includes Service Pack 3. The Enterprise Edition saw the introduction of the /3GB boot flag, which changed the default virtual address space mapping from 2 GB kernel and 2 GB userland to 1 GB kernel and 3 GB userland. It also introduced a PSE36 driver for mapping up to 64 GB memory (although chipsets of the era supported only up to 8 GB.) This version also sees the first introduction of cluster service.