DOS ain't dead

Bug in FreeDOS FDISK 1.3.4 or BIOS? (Developers)

posted by tom , Germany (West), 23.11.2022, 16:22
(edited by tom on 23.11.2022, 18:40)

> Thanks to all for the feedback.
>
> By skimming over the FDISK source code I think I found a possible location
> yielding an off-by-one error:
>
> https://gitlab.com/FreeDOS/base/fdisk/-/blob/master/SOURCE/FDISK/FDISK/PDISKIO.C#L919
>
>
> pDrive->pri_part[index].end_cyl
> =Extract_Cylinder_From_LBA_Value(
> /* */
> (pDrive->pri_part[index].rel_sect
> +pDrive->pri_part[index].num_sect)...
>
>
> I think that should be
>
> pDrive->pri_part[index].end_cyl
> =Extract_Cylinder_From_LBA_Value(
> /* */
> (pDrive->pri_part[index].rel_sect
> +pDrive->pri_part[index].num_sect - 1)...
>
>
> Can anyone please double-check that?

I think that a) is a plausible place and b) looks right.

I also think that all occurences of

xyz.end_cyl = Extract_Cylinder_From_LBA_Value()

should be checked. It's quite horrible software

Complete thread:

• Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 20.11.2022, 19:09
  • Bug in FreeDOS FDISK 1.3.4 or BIOS? - Japheth, 21.11.2022, 08:10
    • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 21.11.2022, 11:21
      • Bug in FreeDOS FDISK 1.3.4 or BIOS? - Laaca, 21.11.2022, 18:21
        • Bug in FreeDOS FDISK 1.3.4 or BIOS? - fritz.mueller, 22.11.2022, 12:06
          • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 23.11.2022, 14:36
            • Bug in FreeDOS FDISK 1.3.4 or BIOS? - tom, 23.11.2022, 16:22
              • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 23.11.2022, 20:23
  • Bug in FreeDOS FDISK 1.3.4 or BIOS? - glennmcc, 23.11.2022, 19:55
    • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 23.11.2022, 20:17
    • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 23.11.2022, 20:52
      • Bug in FreeDOS FDISK 1.3.4 or BIOS? - boeckmann, 24.11.2022, 15:38
        • Bug in FreeDOS FDISK 1.3.4 or BIOS? - fritz.mueller, 24.11.2022, 18:47