ISW dmraid-rc15 fails to activate raid0 due to incorrect cylinder calculation

[Danny]

I was asked by one of the Ubuntu dmraid maintainers to post this here.

I have a pair of ICH8R RAID0 sets whcih were built on dmraid-rc14 (on
ubuntu 8.4)
Upon update to the latest test release of Ubuntu (9.04) neither of the
sets would activate and so I couldn't install.

Upon many attempts and comparisons to rc14 I discovered that
dmraid-rc15 calculates the number of cylinders incorrectly..

Basically on my first RAID set the smallest drive is 9729 cylinders,
so with a RAID0 array 2x9729 is 19458, this is the number of cylinders
that dmraid-rc14 calculates.
dmraid-rc15 on the other hand is a little bad at maths and calculates
it to be 19457 cylinders.
I was thinking that the cylinder count should be even given a RAID0
should be symmetrical to function properly.

My partitions go all the way to the end of the drive and that is why
my extended partition didn't load, to solve this I spent ages resizing
my partitions, the worst was my large drive as its completely NTFS and
it had all sorts of issues.
Once resized dmraid-rc15 worked correctly.

regards,
Danniy