INT 21h/4409h and 440Ah skip documented redirector dependency

[nakatamaho]

Summary

INT 21h/4409h and 440Ah appear to report local device/handle attributes even when the network or file-sharing provider required by the MS-DOS 4.0 reference is absent.

Minimal reproducer

Boot with a valid local drive and ordinary open file, but without SHARE or a network redirector:

1. Call INT 21h with AX=4409h and BL=1 (drive A).
2. Call INT 21h with AX=440Ah and BX set to a valid open file handle.

Expected behavior

The MS-DOS Version 4.0 Programmer's Reference documents error 01h when the required provider is not loaded for both calls. For 4409h it additionally documents error 15 for an invalid drive; for 440Ah it documents error 6 for an invalid handle.

Observed source behavior

At component commit ac16c8a7401526f99787e03babdb2f4223d48fc4, DosDevIOctl returns success for AL=09h after obtaining the local CDS/device attributes, and for AL=0Ah after obtaining a valid SFT. These paths do not check for SHARE or a network redirector. The source is visible at https://github.com/lpproj/fdkernel/blob/ac16c8a7401526f99787e03babdb2f4223d48fc4/kernel/ioctl.c#L143-L206.

References

• Microsoft, MS-DOS Version 4.0 Programmer's Reference, Function 44h, codes 09h and 0Ah: https://www.pcjs.org/documents/books/mspl13/msdos/dosref40/
• Component source revision: ac16c8a7401526f99787e03babdb2f4223d48fc4

Could you confirm whether the local success behavior is intentional FreeDOS compatibility, or whether the calls should report the documented provider-not-loaded error?

[andrewbird]

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