The International Disk Drive Equipment and Materials Association (IDEMA), the industry group which promotes the technological, manufacturing, marketing, and business needs of the disk drive industry, is leading the Big Sector initiative to update computer hard disk drives from 512 bytes to 4,096 bytes (4 Kilobytes) sectors.
IDEMA claims the need to change the hard drive sector size which has been consistent for thirty years, developed as hard disk sizes grew. 
The old 512-byte sectors limited the amount of error correction required to handle more data on the newest drives. Dr. Martin Hassner of Hitachi GST said: “(The) increasing areal density of newer magnetic hard disk drives requires a more robust error correction code (ECC), and this can be more efficiently applied to 4096-byte sector lengths” in a 2006 TechWorld article. According to the trade group, the change to 4 Kb sectors will allow hard drives to continue to grow to 2 Tb in size.
Western Digital (WDC) is the first manufacturer to release products under this initiative. WD calls these drives Advanced Format. According to an article at AnandTech, In order to reach the 2 Tb size Western Digital and other drive manufacturers have developed a 512 b emulator which resides on the drive controller for the Microsoft (MSFT) Windows 5.x family (Windows 2000, XP, 2003, Windows Home Server) which are unaware of 4 Kb sectors.
AnandTech says the emulators will allow Windows 5.x systems to continue to think they are seeing 512 b but there are still problems. The article reports that the Windows 5.x family has a habit of misaligning the first disk partition under the new system which will result in poor default performance. The Windows 6.x family (Vista, 2008, Win7) and later are programmed to take into account the alignment issues. This also creates issues for imaging software. Drive imaging software like Norton’s Ghost needs to be 4 Kb aware. Otherwise, it may inadvertently create misaligned partitions with any Windows product. The article claims that all current imaging products will write misaligned partitions and/or clusters.
Linux and Apple (AAPL) Mac OS X are not affected by this issue. Western Digital has tested modern versions of both operating systems and officially classifies them as not-affected. They also found that Linux and Mac OS X drive imaging products are also unaffected.
Western Digital is offering two solutions to solve the misalignment issue. The first solution is specifically geared towards Win 5.x. The first option is to use an offset created by jumpering pins on an Advanced Format drive. This will force the drive controller will use a +1 offset. This crude hack means the operating system is no longer writing to the sector it thinks it’s writing to. Jumpering is simple to activate and effective in solving the issue on a PC with a single partition. If multiple partitions are installed this hack cannot be used because the offset can damage later partitions. The offset can not be later removed without repartitioning the drive, because that would break the partition table.
The second method of resolving misaligned partitions is through the use of Western Digital’s WD Align utility available online from WD. The utility moves a partition and its data from a misaligned to an aligned position. This is the recommended solution for using multiple partitions under Win 5.x, along with correcting any misaligned partitions generated by imaging software. The utility also serves as the only way to find an Advance Format drive without physically looking at it.
AnandTech calls the WD Align utility the recommended solution for single-partition drives being used under Win 5.x too since it prevents breaking the partition table. The amount of time needed to run the utility depends on the amount of data that needs to be moved and not the partition size (it simply ignores empty space), so it’s best to run the utility immediately after creating a partition or installing Windows, as there’s less data to move around.
The first Advanced Format drives are WD Caviar Green drives using multiple 500GB platters which are now available. There are two ways to identify these drives:
1) They all have 64 Mb of cache – the first WD Caviar Green drives to come with that much cache; and
2) They all have EARS in the drive model number, e.g. WD10EARS.
It seems that WD is not pushing these drives as part of any major product launch. The new drives are quietly entering the marketplace. The IDEMA plan called for everyone to have 4 Kb sector drives by 2011, so there will be similar soft-launches from the other manufacturers over the next year. It is reasonable to expect all the HDD manufacturers to have similar problems with Win 5.x, All of the vendors will have to support WinXP, in one way or another until at least 2014, when extended MS support for WinXP ends.
Ralph Bach has been in IT long enough to know better and has blogged from his Bach Seat about IT, careers, and anything else that catches his attention since 2005. You can follow him on LinkedIn, Facebook, and Twitter. Email the Bach Seat here.