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Ranish Partition Manager revived (Announce)

posted by boeckmann, Aachen, Germany, 19.11.2022, 21:03

One question of a more technical kind.

I managed to modify RANISH to use LBA disk access if provided by BIOS and modified it from top downto its disk access functions to only use LBA addressing (with CHS reads / writes as a fallback if no LBA BIOS is provided).

I am now confused that my BIOS, when querying drive parameters via INT 13 function 48h returns a totally different geometry in comparison to what function 8 returns. While function 8 is giving me CHS values 1024,255,63 as expected for a large disk, function 48 seems to passthrough the CHS values the IDE controller returns, that is 16383,16,63.

I am now wondering which one to trust when creating partitions and MBR entries. My guess would be that I use the geometry returned by function 8 for compatibility reasons and function 48 to get the disk size (total sectors). From both values one could calculate another "virtual" cylinder count.

I am missing something essential here or could that be the way to go forward?

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