[parted-devel] [PATCH 1/2] libparted: check PMBR before GPT partition table (#805272)

[John Gilmore]

> I don't think this patch is quite right.  The exception should be fixed rather than removed.  If it is supposed to be a GPT disk, then we should fix the broken PMBR.  If it is not, then we should zap the GPT and then fail to recognize the disk as GPT ( thus allowing it to be recognized as DOS ).

At startup, Parted should not be "zapping" anybody's disk drive, no
matter how invalid it looks.  The drive should remain read-only until
if-and-when the user explicitly commands parted to write something.

Occasionally, in the distant past, I have had to write zeroes over the
first blocks of a disk (using "dd") in order to get parted to let me
relabel it without getting confused by its prior contents.  Perhaps
parted should have a "zap" command that allows some area(s) of the
drive to be zeroed without using a separate program.  Then Parted could
produce a diagnostic message when it detects this kind of mangled GPT,
suggesting that the *user* "zap" the drive.

	John