Mapping a network drive letter, means that a resource that is available for sharing on another networked system will be assigned a local drive letter. For example, PC000 has shared a folder named ROSHARE as read-only. Network aware operating system functions and programs can refer to this shared resource by its UNC name: \\PC000\ROSHARE and gain access to the files in the folder on the other system. Functions and programs that are not network aware or compatible, will not be able to access the files. To make all files in the shared folder accessible to the all OS functions and programs of the local system assign the distant folder a local drive letter.
The detailed operation below concerns mapping a network drive to a user's home directory on a Netware 3.12 server, but the same principles apply in mapping a network drive in a NetBEUI Peer-to-Peer network except of course that the UNC names will be particular to the names of the machines and their shares and the "Reconnect at Logon" should be left unchecked because a Peer machine will not be as reliable as a server. In the event that the peer is not available, this choice will result in very long delays while the service attempts and retries the attempts to contact the remote host during the startup phase.
Obviously in order to perform this exercise then the system must be networked to at least one other system and both systems must have the File and Print Sharing Service installed, it does not install by default in Windows 98. See Setting Up a NetBEUI Peer-to-Peer Network, Renaming a Windows 98 PC, Sharing a Folder in Windows 98, Controlling Master Browser Elections in Windows, for related topics.