I don't think that sector sizes other than 512 are supported for hard drives. (Floppy drives are a different story.)
Things that used non-standard sector sizes had to supply their own formatting routines and their own BIOS extensions. The original Bernoulli box is a good example: it used 256 byte sectors. CD-ROMs use 2048 byte sectors. That's not relevant for FDisk, but it's also hidden by the redirector interface. -Mike On Wed, Mar 15, 2023 at 10:03 AM Bernd Boeckmann via Freedos-devel < freedos-devel@lists.sourceforge.net> wrote: > Hi, > > while hacking on FDISK and having some thoughts about different sector > sizes I stumbled upon the problem that the extended INT13 function 48 may > return a sector size != 512 while the INT13,0X functions always seem to > operate on „virtual“ 512 sector sizes. > > Unsure how to handle this case I tried to find some hints in the FreeDOS > Kernel source. In INITDSK.C the sector size returned by INT13,48 is simply > ignored and only the total sector count is used to determine the size of > the disk. This may be because in reality it is a non-existent problem > (values other than 512 are not encountered „in the wild“). There is also a > MAX_SEC_SIZE 512 definition leading me to the conclusion that sector sizes > of > 512 are not supported at all? > > My initial idea for how to handle this in FDISK until a better solution is > found was to sort of work-around it by reverting to CHS functions - with > all the drawbacks this has - if the sector size returned by INT13,48 is not > 512. Then at least the first ~8GB could be supported. > > But I would be glad if someone with more knowledge in that area could > point me in the right direction, especially under the assumption of staying > compatible. > > Greetings, Bernd > > > > _______________________________________________ > Freedos-devel mailing list > Freedos-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freedos-devel >
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