NetBIOS

SNA (System Network Architecture) was too complex for PC and so IBM hired a company call Sytec and together created a product called PC Network. PC Network was a LAN system designed to support abotu 80 nodes at best and no provision for routing. Microsoft used the NetBIOS API to transport SMB file service messages. A redirect program was created simply to look up disk drive (e.g. S:) or port reference (e.g. LPT3:) from a table. If the device was not found in the table, it was passed down to DOS. Otherwise, the call would be redirected.

Using SUBST, an alias can be created for a long path name (e.g. SUBST S: C:\Program). Using NET command, a drive letter could be used to map to a remote file service (e.g. NET use N: \\SERVER\fileshare1)

NetBIOS is a session layer (layer 5) API. The API made a number of assumption about the underlying network. Three basic services must be implemented - Name Service, Datagram Service and Session Sevice.