Role of INTERSVR in MS-DOS 6.22 Networking

This article explains the function and operational role of the INTERSVR.EXE utility in MS-DOS 6.22. It covers how the program transforms an MS-DOS machine into a file and resource server, how it negotiates connections with a client system using direct cable links, and the specific duties it performs to enable drive redirection and file transfers between legacy computers.

The INTERSVR (InterLnk Server) utility is the server-side component of the InterLnk networking suite built into MS-DOS 6.22. Its primary function is to share local resources—including hard disk drives, floppy disk drives, and printer ports—with another computer connected via a physical cable. While modern networking relies on Ethernet and TCP/IP, INTERSVR provides a lightweight, peer-to-peer connection that requires no network interface cards (NICs) or complex protocol configurations.

To establish communication, INTERSVR relies on a direct serial (null-modem) or parallel (LapLink/bidirectional) cable connected between the serial (COM) or parallel (LPT) ports of two machines. When launched from the command line, INTERSVR scans the host machine's communication ports, initializes the hardware interface, and continuously listens for requests from the client machine running the INTERLNK.EXE device driver.

Once a connection is established, INTERSVR assumes full control of the host machine's resources for the duration of the session. It intercepts input/output requests transmitted over the cable from the client system, reads or writes the requested data on its local storage volumes, and returns the results to the client. This allows the client computer to view and manipulate the server's storage as though the drives were locally attached, assigned to extra drive letters (such as D:, E:, or F:).

A key characteristic of INTERSVR is that it is a dedicated, blocking utility. Running the command locks the host computer into a dedicated server state, displaying a real-time connection status screen that details port activity, transfer speeds, and mapped drive letters. Standard MS-DOS multitasking is not supported; therefore, the host machine cannot be used for other local computing tasks until the server session is explicitly terminated by the user.

In practical environments, INTERSVR served as an essential tool for data migration, system maintenance, and software distribution. It allowed administrators and users to transfer files quickly between desktop systems and portables, back up data from failing hardware, and bootstrap software installations onto machines that lacked optical media or working floppy drives.