Pass the u option to fdisk, and you can ignore the heads/cyl/spt info. The u option changes the display/entry units to sectors (each sector is 512 bytes). So with the u option the partition start is just starting_sector * 512, and you can pass this value directly as the -o offset value to losetup.
You can change the heads, cylinders, and spt in fdisk, but I have never seen a need to. The fdisk man page has a good section on disk geometry. Philip Prindeville wrote: > So that it matches any partitioning/formatting done on the target's BIOS. > > Also, if the geometry is C=992/H=64/S=63, and the starting cylinder is > shown by fdisk as 100, then how do you calculate the -o argument to > losetup to figure out the offset in bytes? > > Thanks. > > > On 12/02/2009 07:25 PM, Terry Markovich wrote: >> As far as I know, the number of heads and sectors-per-track bximage >> reports is just a convenient fiction. Cylinders * heads * spt * >> 512(block size) = image size. >> >> Why do you need that specific geometry? >> >> Terry >> >> Philip A. Prindeville wrote: >> >>> I'm trying to "pre-image" Astlinux for a CF of a given size and geometry, >>> but when I do: >>> >>> ./bximage -q -hd -mode=flat -size=1953 runnix.img >>> >>> fdisk reports back to me that the partition table of the image runnix.img >>> is C=3968, H=16, S=63. >>> >>> I need it to be H=64, S=63 to be correct. >>> >>> Anyone know how to force "bximage" to a particular geometry? I was looking >>> at the documentation: >>> >>> http://bochs.sourceforge.net/doc/docbook/user/using-bximage.html >>> >>> and that doesn't seem to be an option. >>> >>> Anyone? >>> >>> Thanks, >>> >>> -Philip >>> > > > ------------------------------------------------------------------------------ > Join us December 9, 2009 for the Red Hat Virtual Experience, > a free event focused on virtualization and cloud computing. > Attend in-depth sessions from your desk. Your couch. Anywhere. > http://p.sf.net/sfu/redhat-sfdev2dev > _______________________________________________ > Astlinux-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/astlinux-users > > Donations to support AstLinux are graciously accepted via PayPal to > [email protected]. > ------------------------------------------------------------------------------ Join us December 9, 2009 for the Red Hat Virtual Experience, a free event focused on virtualization and cloud computing. Attend in-depth sessions from your desk. Your couch. Anywhere. http://p.sf.net/sfu/redhat-sfdev2dev _______________________________________________ Astlinux-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/astlinux-users Donations to support AstLinux are graciously accepted via PayPal to [email protected].
