On 12/04/11 11:08 AM, fred smith wrote:
> On Sun, Dec 04, 2011 at 10:24:00PM +0800, Ho Chaw Ming wrote:
>> > Check your bios, and make sure that you did not have IDE mode enabled and
>> > AHCI is selected .
> Also, is this one of the "Green" series of WD disks? Those have
> a 4KB sector size, not the old/traditional 512B sector size. This has
> performance ramifications in that you must have partitions begin on
> a sector boundary or performance goes to the dogs. There are a number
> of articles about it on various geek sites, sorry I can't point you
> to one offhand.
many newer disks use this same 4k internal sectoring. the drives still
*look* like they have 512 byte sectors to the outside world, but its
very important for performance to get your partitions properly aligned
on a 4k boundary, and ideally your file system uses 4K (or multiple of
4k) as its block size.
sadly, the default fake CHS (cylinder head sector) mapping left over
from legacy PC architectures ends up with a 255 512b sector 'track', and
MBR partitioning defaults to using track or cylinder boundaries, so the
first partition starts at an odd location if you use legacy tools like
fdisk.
--
john r pierce N 37, W 122
santa cruz ca mid-left coast
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