IT Manager's Handbook: Getting Your New Job Done

Microsoft's Windows NT and 2000 Server products, Novell's Netware, and all the versions of Unix are a category of software known as network operating systems (NOS). Unix has been around the longest, Novell was the first to gain popularity in the corporate environment, and Windows NT 2000 Server is the most recent entry but has gained enormous ground.
Speaking generally, Unix is considered to be the best choice for very critical and large-scale needs. Novell's reputation for reliability and stability comes from its years of experience with a very large installed base. Windows NT Server (whose latest incarnation is called Windows 2000) is favored as the NOS that provides the easiest integration with other popular applications used in the corporate environment (e.g., those also from Microsoft). Windows NT Server is also favored by those trying to reduce the support headaches (e.g., finger-pointing) that can occur when an environment consists of products from multiple vendors.
Choosing among these three technologies can be very difficult. There are issues of performance, scale, reliability, support, administration, costs, and hardware and software compatibility that you must consider.
The issue of hardware compatibility is critical. In regard to hardware, Novell only runs on Intel devices, Microsoft NT Server currently only runs on Intel and DEC's Alpha boxes, and Unix runs on a variety of platforms (although that selection can be significantly limited by each Unix flavor's vendor).