DOS ain't dead - DOSLFN 0.42

DOSLFN 0.42 (Announce)

posted by ecm , Düsseldorf, Germany, 18.08.2025, 14:15

> > Good. However, will the FD fix have any negative impact on other DOSes,
> > i.e. performance degradation?
>
> Not in MS-DOS (in my admittedly limited test); didn't try anything else.
> (I suspect other DOSes perform the flush internally.)

I traced the int 25h and int 26h handlers of lMS-DOS (based on MS-DOS v4.00) and didn't notice any point at which buffers are queried, flushed, or updated. The request is just passed directly to the device driver. There is some code for the "secondary cache" which I disabled.

As another note, MS-DOS Debug explicitly calls int 21h function 0Dh both before and after calling int 25h or int 26h.

---
l

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Complete thread:

DOSLFN 0.42 - jadoxa, 17.08.2025, 08:05 (Announce)
- DOSLFN 0.42 - Japheth, 18.08.2025, 12:13
  - DOSLFN 0.42 - jadoxa, 18.08.2025, 13:27
    - DOSLFN 0.42 - ecm, 18.08.2025, 14:15
      - DOSLFN 0.42 - tom, 23.08.2025, 20:06
        DOSLFN 0.42 - jadoxa, 24.08.2025, 01:48
- DOSLFN 0.42 - roytam, 29.08.2025, 01:41
  - DOSLFN 0.42 - jadoxa, 29.08.2025, 02:34