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MS-DOS v7.10 disk sector access function 7305h: Error code? (Developers)

posted by ecm  , Düsseldorf, Germany, 05.12.2025, 18:38

The interrupt list doesn't specify what error codes can be returned by int 21h function 7305h, just stating:

> Return: CF clear if successful
> CF set on error
> AX = error code

Trying to access an invalid sector as in l 100 A: 1000000 1 or trying to read from a dosemu2 mfs-redirected drive like l 100 C: 0 1 using my debugger results in a return with CY, ax=020Ch.

That doesn't seem to match any error codes known to DOS for normal int 21h functions. But it does seem like what int 25h returns in ah and al. So apparently this function returns errors in the int 25h/26h style?

The interrupt list should specify this.

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Complete thread:

• MS-DOS v7.10 disk sector access function 7305h: Error code? - ecm, 05.12.2025, 18:38 (Developers)
  • MS-DOS v7.10 disk sector access function 7305h: Error code? - tkchia, 13.01.2026, 16:57
    • Interrupt List updates - ecm, 13.01.2026, 19:26
      • Interrupt List updates - tkchia, 22.01.2026, 17:04