GPT

[Richard W.M. Jones]

On Sun, Apr 22, 2012 at 11:23:55AM -0700, John Reiser wrote:
> > Is there a compelling reason to want GPT?  The format itself is better
> > than MBR, but unless I required (a) disk > 2TB or (b) lots of primary
> > partitions, I wouldn't worry ...
> 
> GPT is more robust in some ways.  GPT keeps a redundant copy of its info:
> at the far end as well as at the beginning.  [To "erase" a GPT requires
> zeroing out both copies.]  GPT info has a checksum which aids detection
> of inadvertent changes.  Each partition can be accessed in only two seeks
> (GPT then destination) as opposed to searching a linked list (1 seek per
> link after the first 4); reading fewer blocks lowers exposure to
> media errors.

Yeah I'm well aware of precisely how GPT works, and I said it's a
better format.  My point is that it's not necessary if you're _not_
using the two main advantages (a) and (b) above.  In practice the PT
format makes no difference to seeks or speed, because the kernel reads
it once and keeps it in memory.

Rich.

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