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Re: Support for 4KB sectors size disk ?

On Jun 3,  1:22pm, Arnaud Lacombe wrote:
} On Mon, Jan 11, 2010 at 6:35 PM, Tobias Nygren <> 
} > On Mon, 11 Jan 2010 19:40:32 +0000
} > David Laight <> wrote:
} >> On Sun, Jan 10, 2010 at 04:45:24PM -0500, Arnaud Lacombe wrote:
} >> >
} >> > I quickly asked on IRC, but didn't get an answer. Do we have native
} >> > support for disk with 4KB sector size in non 512B-legacy mode ? These
} >> > disks start to be available in retail (in particular the WD Green
} >> > series with cache of 64M) and are quite attractive.
} >>
} >> Does windows support these disks ?
} >> Are they bootable ? If so where does the boot code sit ?
} >>
} >> In which case what does the MBR partition information look like ?
} >> Especially when there are extended partitions ?
} >
} > I've yet to get my hands on one of those, but as I understand it, the
} > disk's firmware provides transparent 512-byte legacy translation, and
} > this is the way the drive boots up. So, we should be able to use those
} > WD disks out of the box.
} > By making sure file system blocks are aligned to physical 4KB boundaries
} > you can still tap in to most of the performance benefits.
} yes, it seems that's what is happening. Some parallel thread on a
} FreeBSD forum: So
} there is still a few time before "real" native 4096B-sector-sized
} disk.

     Although at one time it was common to be able to format drives
with different sector sizes, that was over two decades ago.  It is
doubtful that any current operating system would be happy with a hard
drive that had a sector size other than 512 bytes.  Thus they can't
change that until current OSes become an historical footnote.

     I don't know what "a few time" is supposed to mean, but it will
probably be at least five years before this becomes a major concern.
The main thing for the moment is to make sure new partitions are
aligned to 4 KiB boundaries and make sure that the block / frag size is
a multiple of 4 KiB.  These are minor changes that could easily be done
today as they don't affect anything fundamental.  The bigger change of
being able to handle sector sizes other than 512 bytes can be worked on
over time.  This is something that has been wanted for a long time.  We
just have a bigger impetus to do it now.

}-- End of excerpt from Arnaud Lacombe

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