Re: replacing boot and only disk drive
On Sun, 23 Nov 2014 12:14:25 +0100, Pascal Hambourg wrote:
> Pascal Hambourg a écrit :
>> Hendrik Boom a écrit :
>>
>>> Unless the MBR or something related to it contains information about
>>> the size of the entire disk, which will now be wrong.
>>
>> 2) If Windows boots from UEFI, I suppose that the original disk
>> partition table is in the GPT format. This format stores two copies of
>> the GPT header, one at the beginning (primary header) and one at the
>> end of the disk (secondary header). Each header has a pointer to the
>> other, so in a way the primary header has a reference to the end of the
>> disk where the secondary header is located. So, if you use dd to copy
>> the whole disk, the secondary header will not be at the end of the new
>> disk.
>> Maybe tools such as gdisk can fix this.
>
> Looking more carefully, there is more than just the address of the
> secondary GPT header. The GPT header contains also the last usable
> address for partitions which is near the end of the disk, just before
> the secondary partition table. Also, the protective MBR contains a GPT
> partition of the size of the disk - up to 2 TiB due to limitations of
> the MBR partition table format.
>
> See <http://en.wikipedia.org/wiki/GUID_Partition_Table>
>
> However, parted will detect that the disk is bigger than the partition
> table reports and ask to fix it. gdisk allows to fix it too.
The laptop now uses MBR partitions. Since the new drive is only 2T, I
don't expect to need GPT. Thanks for the details, though I won't need to
worry about these until my *next* hard disk enlargement. And ... will
Windows XP know what to do with GPT? But maybe by then I will have
successfully left Windows, even for the very last commercial applications.
-- hendrik
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