Hallo Herr Ralf Quint, am Mittwoch, 1. März 2023 um 18:08 schrieben Sie:
> On 3/1/2023 8:22 AM, Bernd Boeckmann via Freedos-devel wrote: >> Hello, >> >> I am now reaching a state where I think that FDISK not any longer breaks the >> partition layouts created by itself. >> >> However, there is at least still one MAJOR flaw when dealing with partition >> layouts created by other partition managers: >> >> If there exists an extended partition with a start address not aligned to >> cylinder boundaries, the position and size determination for logical drives >> is completely messed up. >> >> For example: While continuing to cylinder-align the logical partitions, this >> is only reflected by the CHS values and not by the corresponding LBA sector >> numbers. CHS and LBA sectors get out of sync because of some wired mix of >> doing LBA and CHS calculation. A problematic line is for example: >> >> https://github.com/boeckmann/fdisk/blob/2c7da2178c097792c3642e73eeb319330e122c71/SOURCE/FDISK/PCOMPUTE.C#L189 >> >> Here the relative starting sector gets set unconditionally. But that is >> wrong in case the extended partition does not start on a cylinder boundary >> while the logical still gets aligned to it. >> >> I must confess that I do not really know how to solve this issue without >> being in danger to completely break everything and want to ask: >> >> a) If someone has an idea of a clever solution without rewriting the (sadly >> large) calculation routines. >> >> b) If it would be ok (at least as an interim solution) to make FDISK refuse >> handling disks with such type of partition layout, because the user must >> have another partition manager to create such layouts anyway. While not >> being optimal, I think this is better than letting FDISK break things. >> >> Greetings, Bernd > The reason why partition boundaries are aligned on cylinder boundaries > is that a lot of other OSes also rely on that. any example of this? I don't any (not completely braindead) operating system would rely on that; it's just the way that FDISK and friends place partitions on the disk. I don't think FORMAT or file systems ever relied on cylinder boundary alignment; at least they shouldn't. Tom _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
