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New HD sector size may impact XP users

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BobA:
Sector size change from 512 bytes to 4096 bytes is already here for some HDDs.   Some WD drives have a jumper but different manufactures may not. Since so many cabs use XP this may become a factor when chosing your next HDD.

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SavannahLion:
edit: forget it, just mindless yammering on my part

MonMotha:
FWIW, you can make these work fine if you manually move the partition one more (512 byte) "sector" in when you do the install.  That will align the partition to a 4096 byte physical sector boundary vastly reducing the number of read-modify-write cycles the drive has to perform.  XP will still do lots of 512 byte transfers, but at least they'll be aligned in a way that minimizes the nastiness.

IIRC, WD also ships a utility to re-align existing XP NTFS partitions for you.

romshark:
Bought a new one of these types of drives for my Windows 7 Notebook PC (it originally had 2 200GB drives, now it's a 320GB and a 750GB). It even has a warning about XP and older systems right on the label.
However, I tried it in an external USB drive enclosure, and it worked fine with my XP system and my Home Server (Windows Server 2003, I think) without any patches or running "WD Align". Thinking it was maybe something with the enclosure, I hooked it up directly to the SATA and power cables inside my XP desktop. Everything still recognized and accessed OK.
So maybe Windows actually patched the OSes to overcome this problem. Take into account, you might not be able to install XP onto a drive like this, since the installer and XP itself at first won't be patched.
Also couldn't test with the Home Server, since all my bays are currently occupied in it. But my server has 2.1TB free out of 3.41TB, so I should be safe for a while.
Drive was formatted in Windows 7 when first received, but I don't think that would've changed anything.

MonMotha:
It will still *work*, but performance will suffer (often by quite a bit).  What happens is that Windows will do lots of 512byte accesses and lots of larger accesses (1024byte, 2048byte) that span multiple sectors even though they're still smaller than the actual physical sector size.  For reads, this isn't a huge deal (though it does incur a performance penalty), but for writes this is pretty bad.  It means a read-modify-write cycle has to be done for each physical sector the write touches.  With the partition unaligned (as is the default on XP), almost all writes will have this happen.  Just aligning the partitions fixes a lot of this (even though Windows still doesn't know that it should perform 4096 byte transfers when possible) since it tends to lessen the chance that a write will span multiple physical sectors.

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