---- Le jeu., 20 mai 2021 07:58:38 -0400 Eric Auer <e.a...@jpberlin.de> écrit
----
>but the actual problem is that Paul runs into - apparently BIOS
>related - attempts to switch to protected mode in spite of
>EMM386 already using that. The problematic code - Paul writes
Yeah, it make sense... it must need to return to protected mode to execute the
UEFI driver...
It may be the case with other drivers than hard disk too...
Which make me think my system would probably be more happy if the FreeDOS
kernel was
booted in VM86 mode by a UEFI program, and extended and expanded memory were
implemented by UEFI services. ;-)
>Another possible work-around could be to load UHDD, probably
>before EMM386, if EMM386 has to be used at all: Because UHDD
>handles many aspects of disk I/O by directly talking to the
>hardware,
Well... I doubt it will be able to speak to an AHCI only chip (no ide).
the BIOS will be invoked less often. And if you are
lucky, exactly those BIOS functions which trigger protected
mode conflicts could get bypassed.
This could be enough to let some protected mode apps work,
although probably not very stable? I have no clear intuition
about whether chances are better with or without EMM386.
>I still worry about the reserved 4 kB starting at 0x00058000,
>how would you make sure that DOS apps do not touch the area?
I worry too. Not sure at all how to handle it.
_______________________________________________
Freedos-devel mailing list
Freedos-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/freedos-devel
