The 2TB Barrier

Pretty much all HDDs (and SSDs) are addressed using a scheme called Logical Block Addressing (LBA). The method is very, well, logical. Storage is addressed linearly, regardless of how the hardware itself is accessed. You start at LBA 0 and you go all the way up to the last address in your device. The number of LBAs you can address is a function of your hardware and the style of partition you’ve applied to your drive.

Master Boot Record partitioning is by far the most common on PCs today. LBA 0 contains the Master Boot Record (MBR) and your BIOS looks at the contents of LBA 0 to determine how and what to boot.

Now LBAs under MBR partitions are addressed using 32-bit values, the maximum of which is 2^32 or 4294967296. Each LBA on a hard drive corresponds to a 512-byte sector value (even on current 4K advance format drives, they still appear as 512-byte sector drives to the OS), so the largest partition you can have in a MBR partitioned drive is 4294967296 * 512-bytes or 2,199,023,255,552 bytes.

Hard drive manufacturers define 1TB as 1 trillion bytes. If we use that definition then the largest 32-bit MBR partition would be 2.199TB (2,199,023,255,552 bytes / 1,000,000,000,000). If we define 1TB as 1024^4 bytes (TiB) then the largest 32-bit MBR partition would be 2TiB (2,199,023,255,552 bytes / 1,099,511,627,776). Either way, with a 3TB drive there’s no way we’re getting a single 3TB partition using MBR.

In use on all Itanium and Intel based Macs (among other systems) is GPT (GUID Partition Table), and a feature of GPT is 64-bit LBA support.

With 64-bit LBAs the largest 512-byte sector drive we can address is 9.4ZB (Zettabytes - 10^21 or 2^70 bytes depending on if you’re counting in base 10 or 2). That’s an absurd amount of data.

GPT drives are supported as data drives in all x64 versions of Windows as well as Mac OS X and Linux. Below we have some screenshots of creating a GPT drive in Windows and OS X:


GPT Partition in Windows 7


GPT in Mac OS X

You’ll note that I said data and not boot drives. In order to boot to a GPT partition, you need hardware support. I just mentioned that your PC’s BIOS looks at LBA 0 for the MBR. Your BIOS does not support booting to GPT partitioned drives. GPT is however supported by systems that implement a newer BIOS alternative: Intel’s Extensible Firmware Interface (EFI).

Intel based Macs don’t use a BIOS and instead have an EFI which allows them to boot to GPT drives. Most PC motherboards however do not have EFI support, and those that do may have bugs associated with the implementation.

Case in point is Intel’s DX58SO, which just happens to be my default storage testbed. The good news is that Intel has deployed EFI on many of its motherboards. The bad news is the DX58SO (and potentially other models?) has some serious issues when you enable EFI.

The biggest problem I had was USB support dropping out completely when I enabled EFI on the Intel board. This is apparently a known issue and doesn’t affect all USB peripherals, but it prevented my keyboards and mice from working - which also meant that I couldn’t install Windows.

To make matters worse, even with EFI disabled I couldn’t get a 2TB partition created and installed to. The Windows 7 installer would simply complain that it couldn’t be installed to that drive.

There’s an odd bug with the DX58SO that lets you create a single 3TB partition with the SATA controller in Native IDE mode, and with that you can complete a full Windows 7 install. Note that in Native IDE mode you lose performance benefits like NCQ so it’s not ideal, but it’s the only way to get the drive with Windows installed on it.

Intel is aware of the bug and is working on a solution. Apparently the DP55KG board should work perfectly fine but that didn’t help me in this situation. Update: Intel has since sent me a beta BIOS that addresses a number of these issues, I'm playing with it right now but it didn't make the cut for use in this review. Thankfully it looks like Intel is aware of the problem and is actively working on a solution. I've also asked Raja to pay closer attention to EFI support in his motherboard reviews going forward.

My experience with the Intel board and installing Windows with this 3TB Seagate drive pinpoints why we don’t have an internal drive option for the 3TB Barracuda XT: the hardware isn’t ready for it yet. Consumers are used to buying a new hard drive and just sticking it in their system. With the requirements for EFI and GPT, we’re going to need a lot more effort from the motherboard manufacturers and clear messaging from the drive makers to avoid a lot of confusion in the marketplace.

Not Just Another Upgrade 3TB Internal Drive Performance - Nothing to Get Excited About Yet
POST A COMMENT

79 Comments

View All Comments

  • gigahertz20 - Monday, August 23, 2010 - link

    The heat problem mentioned in this article makes me wonder why engineers fail to correct issues like these. It can't be that much more expensive to put a fan in the unit along with more ventilation. If it was me, I would have installed a fan inside the enclosure that would only turn on when the unit reaches a certain temperature. That way it still stays quiet, but when it gets heated up to the point where it can affect its life span, the fan will cool it down. Reply
  • MarkLuvsCS - Monday, August 23, 2010 - link

    lol so first they have a bit of an issue with some firmware and such, but now they decide their 3TB drives should double as coffee warmers?!?!?

    I used to consider Seagate pretty good mfg but honestly ever since their 1TB fiasco days I don't even consider them. I certainly don't want to see less competitors out there but they really need to get their acts in order.
    Reply
  • siuol11 - Monday, August 23, 2010 - link

    I used to use Seagate exclusively... I had a RAID 0 array of 7200.10 320's, and one failed completely, erasing most of my papers and photos I'd saved from college. I also had a 500GB 7200.11, one of the few to not suffer from the .11's random fail bug- 5 months in to using it, the SATA connector snapped off (there was nothing putting pressure on it, it just snapped. I booted up my computer one morning and it couldn't find the drive). My last Seagate was a 1TB 7200.12, which started getting massive amounts of bad clusters 10 months in to using it. Thankfully it lasted long enough for me to transfer my files.
    Since then I've switched to Maxtor... I know you can't really use the retail drives in RAID arrays, but at least none of them have blown up on me.
    Reply
  • Belard - Monday, August 23, 2010 - link

    RAID-0 is pretty much pointless... And are more acceptable to failures.

    If your data was that important, then a backup drive should have been used, ESPECIALLY with a RAID-0 setup.

    - MAXTOR is owned by Seagate and both "brands" come off the same assembly lines... Never heard of "Can't raid a retail drive" before. Most OEMs are single drive setups... a drive is a drive.
    Reply
  • xded - Monday, August 23, 2010 - link

    > Never heard of "Can't raid a retail drive" before. Most OEMs are single drive setups... a drive is a drive.

    Not entirely true. The problem is that, in case of errors, the firmware on retail drives will keep trying reading the faulty sector for too long. This delay will make the RAID controller assume that the drive is gone and it will drop it out of the chain. This unnecessarily increases the load on the array due to the subsequent rebuild phase. If then another drive should fail under the increased load, you will most likely lose the whole array, while correcting the unreadable sector in the first place would have been trivial.

    This is why most manufacturers also sell "RAID edition" HDDs which, other than a tweaked firmware, also have a considerably higher MTBF.

    For further information, see here http://en.wikipedia.org/wiki/Time-Limited_Error_Re...

    see
    Reply
  • Belard - Monday, August 23, 2010 - link

    Oh... okay. I've not forgotten about enterprise class drives, for a REAL RAID setup, I wouldn't use consumer grade drives.

    But for most home users, using off the shelf is usually fine. But still RAID-0 is useless compared to the speed to todays drives. The complexity, the overheard and errors aren't worth it.

    Want to improve BOOT up time and startup of your apps, spend $150~$200 for an SSD.
    Reply
  • pcfxer - Tuesday, August 24, 2010 - link

    Complexity? You must be retarded.

    You can geom Mirror, ZFS RAID-Z, HFS+ RAID or use the onboard software RAID.

    If you know what you are doing RAID is fine, but thinking RAID will improve game load speeds is lol-eriffic.
    Reply
  • siuol11 - Monday, October 11, 2010 - link

    Man, I had completely forgotten about this comment till I came back to this thread today. Thanks for the comments guys, I'm aware of all of this. The 2 .10's in RAID 0 were 320's that I was using as data drives, I'm aware that RAID 0 on physical disks doesn't help latency.
    I'm fairly sure Maxtor ans Seagate have different QC mechanisms, which make all the difference in the world... And after failures of 3 successive generations of their drives, I think I'll pass. I'm still pissed that I lost all that stuff (and yes, yes, I know I should have had a backup. It just wasn't possible at that time).
    Reply
  • Wolfpup - Thursday, September 16, 2010 - link

    Yikes, this gives me yet MORE reason to avoid "RAID" 0. Reply
  • adamdz - Monday, August 23, 2010 - link

    But you had a backup, right? So you were able to get all your papers and photos back, right?

    And, yeah Maxtor is owned by Seagate and it was always garbage.
    Reply

Log in

Don't have an account? Sign up now