onic messaging. 2.As an additional service layered upon a general-purpose operating system, such as Unix or OpenVMS.In a International Data Corporation (IDC) white Paper, by Dan Kusnetzky, Kusnetzky argues that stand alone NOS environments provide the highest performance when the only requirements are file and print services. They often are less stable and robust when supporting other functions. When multifunction servers are required, layering NOS functions on a general-purpose operating system becomes the best choice. Kusnetzky addresses the following issues concerning Network Operating Systems: Architecture -- Companies need to be concerned with the architecture of a NOS. Does the NOS support multiprocessor systems? Are these systems supported asymmetric or symmetric multiprocessing systems? Can NOS functions be partitioned to run on more than one processor simultaneously? Does the operating system support multiple microprocessor architectures?Scalability -- Companies expecting a NOS to support small, medium-sized, and large environments using the same NOS need to consider the following questions. What is the minimum and maximum memory, disk cache, and disk supported by each NOS? What is the maximum number of file locks, open files, concurrent clients, servers in any domain, and domains supported by each NOS. Availability and reliability features -- File locking, and various types of client failover when a server fails are important to companies that rely on the network as a critical part of their day-to-day business operations. Clients supported -- Most companies have a broad array of desktop devices. A NOS must support all of the desktop devices being used in a company if it is to be a viable candidate for adoption. Typical devicesthat must be supported are systems running DOS, DOS/Windows, Windows for Workgroups, Windows 95, Windows NT Workstation, Macintosh, OS/2, and Unix. Network printing -- Printing is one of the primary f...
