Resolving MS-DOS 6.22 INTERLNK Path Conflicts

MS-DOS 6.22 manages network pathing and drive letter conflicts through its built-in INTERLNK utility by leveraging ordered block-device driver assignments, explicit drive redirection syntax, and LASTDRIVE allocation boundaries. By establishing client-server links over serial or parallel connections via INTERLNK.EXE and INTERSVR.EXE, the operating system prevents collisions with existing physical, logical, and local-area network (LAN) drives by dynamically reserving drive letters and enabling manual mapping overrides.

Device Driver Load Order and Drive Allocation

In MS-DOS 6.22, drive letters are assigned sequentially as block devices are registered during startup. Pathing conflicts frequently occur when remote INTERLNK drives displace existing network shares or logical partitions.

To manage this, INTERLNK.EXE is loaded in CONFIG.SYS:

DEVICE=C:\DOS\INTERLNK.EXE /DRIVES:3 /NOPRINTER

The system resolves drive availability by evaluating:

Physical floppy and hard drive partitions.
Device-driver-based storage (such as RAM drives).
INTERLNK assigned letters.
Traditional network redirector letters (such as Microsoft Network Client or Novell NetWare).

If INTERLNK.EXE loads before a network redirector, it claims the next available letters, shifting network paths. If loaded after, the network redirector consumes letters up to its configured ceiling, leaving remaining slots for INTERLNK.

The Role of LASTDRIVE

Pathing resolution requires setting the LASTDRIVE directive in CONFIG.SYS. By default, MS-DOS sets the last drive letter to E. If the combined count of physical drives, network shares, and INTERLNK drives exceeds this letter, mappings fail, creating path-not-found errors.

Configuring LASTDRIVE=Z gives MS-DOS full addressing space, allowing distinct letter blocks for local storage, LAN redirectors, and INTERLNK connections without overlap.

Manual Drive Remapping to Eliminate Collisions

To prevent INTERLNK from breaking established local or network environment variables (PATH), MS-DOS 6.22 allows specific letter-to-letter drive mapping. Rather than auto-assigning the next free alphabetical letter, the administrator can explicitly bind client letters to remote server letters from the command line:

INTERLNK G=C

This command maps local drive letter G: directly to the C: drive of the machine running INTERSVR. If an existing network mapping occupies a target letter, the user can cancel or redirect the link dynamically without rebooting:

To cancel a specific conflicting mapping:
```
INTERLNK G=
```
To query current letter routes and verify path resolutions:
```
INTERLNK
```

Resolving Naming and Path Traversal Conflicts

Because INTERLNK relies on DOS-level block redirection rather than UNC (Universal Naming Convention) paths like \\SERVER\SHARE, path resolution depends entirely on maintaining drive letter consistency. If batch files or system paths rely on fixed directories (such as D:\TOOLS), an unexpected INTERLNK mapping can displace drive D:.

MS-DOS 6.22 handles this by allowing the /DRIVES switch inside CONFIG.SYS to reserve a fixed number of slots (defaulting to 3), preventing INTERLNK from arbitrarily consuming letters reserved for later network mappings. Through static mapping definitions and controlled driver loading, MS-DOS isolates INTERLNK virtual drives from existing network filesystem structures.