Some strange behavior with Promise Fasttrak

paul moore paulm2012 at
Tue Feb 8 09:09:27 UTC 2005

 Hi Örjan,

 Found the problem. Windows (or DOS) partitioned the drive for 256 byte
sectors even though the drive has 512 byte sectors. This isn't immediatly
apparent until you start comparing the partition sizes in the partition
tables to what fdisk says. Thanks alot M$!
 From looking at the unpatched code in dmraid, it looks like Heinz was
trying to get around the problem of M$ useing 256 byte sectors for
partitioning and Linux fdisk useing 512 byte sectors. It looks like he was
trying to locate the partitions with minimal use of the partition tables
and treating them as if they were stacked one after the other. This doesn't
always work, especially for extended partitions. The patched version is
written to spec and depends on the partition tables. It works great for
me because I used linux fdisk to create all my partitions B~b. Linux fdisk
manages to hide this when you display your partitions and shows everything
as 512 byte sectors.
 So, how to fix this? Well for starters, how does Linux fdisk find out what
the sector size is, boot sector (possibly)? The partition tables themselves
do not contain any hint as to partition size. You can't really use an
error condition to determine it, it might be a real error. What happens
when some of the partitions are from M$ and some of them are from linux
(God forbid!)? I need to find out how Linux fdist works this out and if
it is a complete solution or a "works for most" solution. At the very
worst, dmraid from the command line could have user interaction to flag
windows partitions and run a config file at boot time. Now that would
solve all the problems, except for user friendliness! Of course you
could always replace dos.c with something as big as dmraid, but jeez.
It might turn into a bigger headache hooking it up than fixing what you
 Hey, Dick Marinus, do you have any ideas or comment on this?

Oh yea Örjan, all I can say is "OUCH".

 All donations and gifts graciously accepted,

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