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Main => Main Forum => Topic started by: BobA on April 15, 2010, 10:20:25 pm

Title: New HD sector size may impact XP users
Post by: BobA on April 15, 2010, 10:20:25 pm
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.

Link To Arstechnica (http://arstechnica.com/microsoft/news/2010/03/why-new-hard-disks-might-not-be-much-fun-for-xp-users.ars/)

Link To Bit Tech (http://www.bit-tech.net/hardware/storage/2010/04/01/the-facts-4k-advanced-format-hard-disks/1)
(Better Article)
Title: Re: New HD sector size may impact XP users
Post by: SavannahLion on April 16, 2010, 12:53:24 am
edit: forget it, just mindless yammering on my part
Title: Re: New HD sector size may impact XP users
Post by: MonMotha on April 22, 2010, 11:14:54 pm
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.
Title: Re: New HD sector size may impact XP users
Post by: romshark on April 23, 2010, 09:31:14 pm
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.
Title: Re: New HD sector size may impact XP users
Post by: MonMotha on April 24, 2010, 09:13:42 am
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.
Title: Re: New HD sector size may impact XP users
Post by: romshark on April 24, 2010, 06:00:13 pm
So does that mean, for the files I copied from home server and XP system (my arcade game and console game files, and some TV shows and Animes), I should move them to my C drive then back to my D drive so that my files are written correctly?  :dunno
Title: Re: New HD sector size may impact XP users
Post by: MonMotha on April 25, 2010, 04:02:35 pm
No.  Moving around files makes no difference.  The issue is that the entire primary partition and file SYSTEM it contains is not aligned for a 4096 byte sector boundary by default on XP.  The tool WD ships with the drive will move the entire partition (and the filesystem it contains) for you to line everything up in a manner that will get the best performance possible.

Vista/7/Linux will still do better than XP since it will ask the drive for its sector size and attempt to merge IO operations into suitable sizes whereas XP just assumes a 512 byte sector for its IO scheduling and optimization.  However, the unaligned partition makes things even worse since it results in lots of unaligned accesses for larger requests under XP, and that's something you can fix reasonably easily.
Title: Re: New HD sector size may impact XP users
Post by: romshark on April 25, 2010, 06:17:31 pm
Just to make sure, I am running the drive primarily on Windows 7. I only used XP to copy some files to the drive, then put it back in.  That's why I was asking if transferring to C then back to D using Windows 7 would cause it to be written correctly, or if any course of action should be taken on my part. Thanks for your help so far, though.
Title: Re: New HD sector size may impact XP users
Post by: MonMotha on April 26, 2010, 12:48:31 am
This all has to do with where the partition is located on the disk.  This is set at the time the partition is created (which would generally be when you installed the OS on it or initially "formatted" it if it doesn't have the OS on it).  If the partition was created with Win7, you should be good as Win7 is aware of 4096 byte sector drives.  If you created the partition with XP, then it probably needs to be moved for optimal performance.  What subsequently accesses the filesystem has no bearing on this. XP may generate some sub-optimal IO schedules compared to Win7 even if the partition is 4096 byte aligned, but this would only affect accesses performed under XP.  Subsequent accesses to the same data under Win7 won't be affected.
Title: Re: New HD sector size may impact XP users
Post by: BobA on May 17, 2010, 07:38:30 pm
Looks like new 3 TB drives are not going to work with many old windows systems.

Extreme Tech Link (http://www.extremetech.com/article2/0,2845,2363872,00.asp)
Title: Re: New HD sector size may impact XP users
Post by: BobA on June 04, 2010, 10:05:01 pm
More info on WD drives.   Seems that it all works out OK if you put in the jumper before installing the drive.

WD ears drives (http://homeservershow.com/wd-ears-drives.html)
Title: Re: New HD sector size may impact XP users
Post by: Havok on June 04, 2010, 10:12:38 pm
Haha - I guess Frizz won't be using the new drives. He's XP hardcore...