From: muta...@gmail.com   
      
   On Friday, April 1, 2022 at 12:31:38 AM UTC+11, wolfgang kern wrote:   
      
   > > Is that the right approach?   
      
   > the BIOS may be able to get correct geometry data   
   > by using Identify-Device (you can do that as well).   
   >   
   > CHS<->LBA conversions must be aware of faked head-   
   > numbers,it were quite common to abuse heads>>tracks   
   > to achieve a larger CHS range. IIRC std-limit=2GB.   
   > 24 bits addressing 512 byte sectors: 2^24*512=8GB   
   >   
   > If the CHS value in the MBR is wrong then blame the   
   > formatting tool. But perhaps you misinterpreted it.   
      
   My MBR uses LBA (I will replace it with a CHS version   
   when I have one), so I only notice a problem when I   
   get to the VBR.   
      
   The formatting tool works fine, as my disk boots even   
   on real hardware.   
      
   But the "physical hard disk" (a VHD) is being moved to   
   a different machine (Hyper V), so I suspect the BIOS   
   there is using different rules.   
      
   Another factor is that the VHD information (512 bytes   
   at the end of the file) is not being used by the tool   
   (freedos under qemu) that formats the disk. I don't   
   know if the VHD records disk geometry.   
      
   I noticed that the MBR doesn't seem to record the   
   disk geometry, so I can't do what I am currently doing   
   with the VBR. ie I need to get disk geometry from   
   somewhere else.   
      
   What options do I have and what are the pros and cons?   
   You mentioned "identify device". What is that?   
      
   Thanks. Paul.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)