The 3 principal elements of a LAN are the network operating system (NOS), the network interface card (NIC), and the transmission medium. Since the dawn of LANs in the early 1980's, the NOS was dominated by Novell's Netware until the late 1990's. Currently, there are competing NOSs, the dominant of which is probably Microsoft's Windows. Discuss the concept of NOS in LANs, and its evolution in the LAN market from its inception by Novell, and market shift from Novell's dominance (for two decades) to the ongoing Microsoft's dominance.