On Sat, 09 Oct 2004 00:35:23 +0800, W I M <[EMAIL PROTECTED]> wrote: > > please take note that partition magic was used to shrink the original > xp partition and that was it, all linux partitions were created afterwards. > i don't think partition magic did wrong. the partitions were in the > right places and mdk92 worked fine until it was upgraded to 10.
The 2.6 kernel though behaves a bit differently. Afaik, XP has a bug that it still uses the buggy CHS values instead of booting from LBA. Linux 2.6 on the other hand does not use the CHS values and instead uses its own mapping from checking sector data as encoded in the partition table, assuming that its mapping is accurate. This hit me real hard though. When I've done the upgrade to Mandrake 10 I noticed that the installer claims to be reading an invalid partition table (which I think is taken from the kernel's mapping). I'm not sure though if it's partition magic's fault as I haven't tried this program yet (too accustomed to ntfsresize() from the linux ntfstools) > i noticed you forced the head count to 255. it was not a safe move to > do. you can actually manually check it first and see where heads start > and end. in other words, you can visually check partition consistency > before doing anything else. and, you just don't change the hd geometry > as recorded in the partition table. if the original head count was not > 255, by changing it, you may have damaged data in all partitions since > cylinder (and partition) boundaries will have changed as well. in fact > your succeeding > post may already indicate misplaced partition data caused by wrong > partition pointers. Strange though that it should be a safe operation (as theoretically claimed) as linux shouldn't really care about the hard disk geometry (only DOS checks the CHS values... and well, Windows XP unfortunately). I have seen reports of Partition Magic (the old ones that is) doing some weird things to partition tables but I've not encountered any until recently. Must be a reaction between the 2.6 kernels and PM's style of non-destructive partitioning. > your post was 2 days ago so i hope you were able to recover your / by > now. re ur xp, it might be best to back it up first; you can just move > out the hd to a desktop and back it up or 'ghost' the partition. i just > hope xp was not damaged when you changed the hd head count. > It's quite hard to recover the partition itself, although it was much easier to recover the files contained in the partition, so I opted for the latter. > just in case you're still at it, you should first establish the original > head count. you can do this by serially scanning the first cylinder and > look for the xp PBR. that should be in the first sector of cylinder 1 so > with that you can already compute for the head count. if it is not 255, > then you should put the computed value back. now working on your mdk10, > since you've lost your /, try booting from the install cd in rescue mode > and do your fdisk, fsck, mount, lilo, etc. from there. At any rate - I'd rather not touch a machine without ascertaining that I could recover it from backup first! Learned it the hard way. -- Paolo Alexis Falcone [EMAIL PROTECTED] -- Philippine Linux Users' Group (PLUG) Mailing List [EMAIL PROTECTED] (#PLUG @ irc.free.net.ph) Official Website: http://plug.linux.org.ph Searchable Archives: http://marc.free.net.ph . To leave, go to http://lists.q-linux.com/mailman/listinfo/plug . Are you a Linux newbie? To join the newbie list, go to http://lists.q-linux.com/mailman/listinfo/ph-linux-newbie
