Re: gpart on macbook air

From: Andrey V. Elsukov <ae_at_FreeBSD.org>
Date: Mon, 01 Oct 2012 12:29:02 +0400
On 30.09.2012 23:06, Raoul MEGELAS wrote:
>> When you are deleting a partition, the kernel completely overwrites  the
>> partition table and PMBR area. You can compare first 34 blocks before
>> deletion and after to see what is going on.
> 
> I can understand that, but i would have thought
> that the deletion of the concerned partition was written preserving others???
> 
> something like:
> 
> - read the gpt table
> - find the offset
> - zeroes the partition entry
> - rewrites the table?
> 
> is not that logic?
> 
> if it is not so, i does not understand this behaviour.
Hi, Raoul,

The kernel has a copy of the partition table in the memory.
When you are deleting some partition, it removes the partition entry
from the memory, constructs updated GPT header and table, calculates
checksums and writes this data into corresponding places.
Any way, this should correctly work.

My guess is that Apple's boot loader detects some changes and
just doesn't want to work. If you think that gpart incorrectly works,
please make a copy of first 34 blocks before and after deletion and
send them to me.

-- 
WBR, Andrey V. Elsukov
Received on Mon Oct 01 2012 - 06:29:11 UTC

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