[CentOS] Curious fdisk report on large disk

Thu Apr 28 13:11:32 UTC 2011
Robert Nichols <rnicholsNOSPAM at comcast.net>

On 04/28/2011 04:06 AM, Timothy Murphy wrote:
> Robert Nichols wrote:
>> Actually, if it were my drive I would just re-create the 4 primary
>> partitions using whatever tool was handy, but giving that extended
>> partition a "normal" type instead.  Once I had the primary partitions
>> looking right, then I'd go in with a hex editor and change the type code
>> to "5" for that partition.  Listing the partition table again with fdisk
>> should now show that everything is back.  (It's very unlikely that any
>> of those secondary partition tables got overwritten when you
>> essentially turned the whole disk into one giant DOS file system.)
> Thanks.
> I think I'd better wait until I have acquired a large external drive,
> and backed up everything!
> But re your method, couldn't I just use fdisk to change the type of sdb4?

No, you can't change a normal partition to one of the "extended" types
or change an extended partition to a normal one.  Making either of those
changes radically alters the way that portion of the disk is viewed, and
I don't know of any partitioning tool that is written to handle that.
In particular, creating an extended partition implies initializing the
secondary partition table at the start of that new partition, and that
might or might not be what you intended if you changed a normal type
to an extended one.

Bob Nichols     "NOSPAM" is really part of my email address.
                 Do NOT delete it.