When I wrote about the drive space increasing on the newest Western Digital drives last week, I knew there must be a reason for the change in the error correction mechanism, and the layout of the drive space.

This morning, Robin Harris, in his column on ZDNet lets us know that the increased space was merely a by-product of the changes, which were really designed to increase reliability, through the ability to error correct much greater lengths of data.

The column speaks of the 4K clusters being a necessary part of the error containment for larger drives, such as the 2TB and larger that are coming soon.

The transition would appear seamless for most users, but those using Windows XP will need to use an Advanced Formatting Utility, and users of certain disk cloning programs will have problems if they wish to restore to one of these 4K sector drives.


If you are in either of these 2 groups:

  1. Windows XP users
  2. Windows users who clone disks with software like Norton Ghost

there are a couple of gotchas if you want to use a 4k drive. Since most drives aren’t 4k and won’t be for another year or more, this may not affect you either. Vista and W7 users are cool except for cloning.

1) Windows XP does not automatically align writes on 4k boundaries, which hurts performance. WD has software – the Advanced Format Align Utility for their drives. I assume other vendors will too when they start shipping.

XP users need to run this utility once to use a 4k drive with a clean install, cloning software or a do-it-yourself USB drive. WD-branded 4k USB drives are already aligned so it isn’t needed for those drives.

2) Windows clone software vendors have yet to implement 4k support. If you clone an XP, Vista or W7 drive you should run the align utility. The cloning vendors need to get on board Real Soon Now. Vendors are welcome to comment on their plans.

What about Macs?

No worries: Mac OS just works with 4k drives – including cloning.

Robin gives a couple of the Western Digital pictures as models ( see above link ), showing how the data is arranged, and it quickly becomes clear why the differences require different write strategies.

I remember hearing about this several years ago, seeing some charts, and thinking it was right around the corner. Though no opinion is given on this, I believe it was the miserable adoption rates of Vista that delayed the changes. Though I wonder why this different write strategy could not have been a part of the Service Pack 3 changes for Windows XP. Most likely Mr. Ballmer could not be convinced of the additional dollars that might arrive at Microsoft’s doors when it was implemented.

No doubt in two more years hardly anyone will think anything about this, and only those who are messing with older drives will find it a problem. Still, since many disk drives do soldier on for years, it should be made enough known so that people are not flailing in the dark when those problems inevitably occur.

The odd thing is that there are no announcements from Hitachi, Seagate, Fujitsu, and Samsung – perhaps that will come at CES in January.


Hitachi_Deskstar_7K2000_HDD_01Disk drives, new all over again – just when you thought they were all figured out.

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