I will look into it. It might have to wait for the next release, but I will see what I can do. I wanted have a pre-release out so I could do the release on Halloween, but looks like it might be Halloween until I get the pre-release out with release to follow soon after (depends on issues raised).
Jeremy On Mon, Oct 25, 2021, 2:52 PM E. Auer <e.a...@jpberlin.de> wrote: > > Hi Jeremy, > > a last minute request for the new kernel release: > > In context of the patch for significant I/O speed improvements > by only splitting transfers around DMA boundaries for drives > where that actually is needed, based on the int 13.48 flags, > > please add a config sys option to override the int 13.48 answer > into either "always avoid DMA boundaries" or "always assume DMA > boundaries are no problem" for all fixed disks (0x80 and up). > > Background: MS DOS, predating the int 13.4x extensions, probably > defaults to never avoiding DMA boundaries for fixed disks and > always avoiding them for floppy. So the config sys flag can give > us MS DOS speed and behavior even when using BIOSes which fail > to properly report their ability to transparently handle any DMA > boundary issues. We would needlessly lose I/O speed otherwise. > > The other option, always avoiding DMA boundaries, would allow > the user to switch back to old FreeDOS behaviour, for example > for benchmark comparisons or for cases where the BIOS claims > to be DMA boundary safe, but actually messes up handling there. > > Thanks :-) As said, the ability to either avoid or not avoid DMA > boundaries would make a big difference for I/O speed. I think it > was Tom who proposed the patch which made us int 13.48 aware :-) > > Regards, Eric > > PS: I think it is NOT necessary to have similar options for > individual drive numbers, because any mismatch between the > reported and actual abilities will usually affect all disks > of the same BIOS and having 2+ broken disk BIOSes is uncommon. > > > > _______________________________________________ > Freedos-devel mailing list > Freedos-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-devel >
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