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Data Storage Upgrades Hardware

WD's Monster 2TB Caviar Green Drive, Preview Test 454

Posted by timothy
from the what-would-this've-cost-in-1999? dept.
MojoKid writes "Today Western Digital is announcing their WD20WEADS drive, otherwise known as the WD Caviar Green 2.0TB. With 32MB of onboard cache and special power management algorithms that balance spindle speed and transfer rates, the WD Caviar Green 2TB not only breaks the 2 terabyte barrier but also offers an extremely low-power profile in its standard 3.5" SATA footprint. Early testing shows it keeps pace with similar capacity drives from Seagate and Samsung."
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WD's Monster 2TB Caviar Green Drive, Preview Test

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  • Powers of 2 (Score:4, Informative)

    by Hyppy (74366) on Tuesday January 27, 2009 @12:18PM (#26624779)
    It's really only 1800 Gigs.
    • by wild_quinine (998562) on Tuesday January 27, 2009 @12:23PM (#26624867) Homepage

      It's really only 1800 Gigs.

      Ah, the drivemaker's kilobyte... [xkcd.com]

      • by pushing-robot (1037830) on Tuesday January 27, 2009 @12:37PM (#26625163)

        Yes. Curse those evil companies, trying to replace our God-given units—like Furlongs, Hogsheads, and Binary Thousands—with evil, communist SI units. The fiends will stop at nothing to pollute the American way of life!

        • Re:Powers of 2 (Score:5, Interesting)

          by jedidiah (1196) on Tuesday January 27, 2009 @12:43PM (#26625289) Homepage

          Yeah... nevermind units that fit in with what's being measured
          or are computationally convenient. What we really need are
          arbitrary metrics created by beaurocrats on a power trip.

          • Re: (Score:3, Insightful)

            Congratulations. You have just stated that powers of 10 are "arbitrary metrics created by beaurocrats[sic] on a power trip."

            Let me explain this in simple terms:

            Powers are two are convenient for machines.

            Powers of ten are convenient for humans.

            It's bad form to present data in an inconvenient format for the user (which, presumably, is human) no matter how "computationally convenient" your algorithm may be. You can use binary calculations all you want behind the scenes, but convert it to a format designed fo

            • Re:Powers of 2 (Score:5, Insightful)

              by MightyYar (622222) on Tuesday January 27, 2009 @01:21PM (#26626009)

              Your argument would carry more weight if the manufacturers were doing this for the benefit of humans. In fact, they mix units - using the 1024-standard units for cache. Tell me mixing units is friendly! :)

              • Re:Powers of 2 (Score:5, Interesting)

                by mmontour (2208) <mail@mmontour.net> on Tuesday January 27, 2009 @01:41PM (#26626401)

                Your argument would carry more weight if the manufacturers were doing this for the benefit of humans. In fact, they mix units - using the 1024-standard units for cache.

                RAM specifications use the 2^x numbering because the device is physically constructed as a square grid of cells with power-of-two numbers of rows and columns. There's a direct mapping between bits on the address bus and the cell that is selected.

                In the early days it was convenient to say that 1024 was close enough to 1000, so RAM sizes were quoted in "KB". However, the error in this increases with each step up in size. By the time you get to the TB scale it's no longer a reasonable approximation.

                Magnetic storage does not have this constraint. The sector size is (arbitrarily) set at 512 bytes and hard drives usually have an even number of read/write heads, but apart from that there are no powers of two. The number of cylinders on the drive, and the number of sectors per cylinder, are arbitrary.

                Communication speeds (e.g. "9600 baud", "100 Mb/s") are also not specified in power-of-two sizes, because they are natively dealing with individual bits and not power-of-two-sized chunks.

                Therefore, there is nothing wrong with saying that a drive is "1 TB with 32 MiB of cache". As long as the manufacturer uses the SI and kilobinary notation correctly, users should not complain. Save your anger for the marketroids at WD who come up with features like "IntelliSpeed" in order to sell you a 5400-RPM drive and make you think you're buying a 7200-RPM one.

                tl;dr version: Just use the damn GiB/GB notation consistently and get over it.

                • Re: (Score:3, Funny)

                  by HTH NE1 (675604)

                  RAM specifications use the 2^x numbering because the device is physically constructed as a square grid of cells with power-of-two numbers of rows and columns. There's a direct mapping between bits on the address bus and the cell that is selected.

                  Magnetic storage does not have this constraint. The sector size is (arbitrarily) set at 512 bytes and hard drives usually have an even number of read/write heads, but apart from that there are no powers of two. The number of cylinders on the drive, and the number of sectors per cylinder, are arbitrary.

                  Now explain flash/solid state memory sizes and the "formatted capacity" of memory.

                  • Re:Powers of 2 (Score:4, Insightful)

                    by mmontour (2208) <mail@mmontour.net> on Tuesday January 27, 2009 @02:56PM (#26627711)

                    Now explain flash/solid state memory sizes and the "formatted capacity" of memory.

                    At a low level flash chips have a row/column nature similar to DRAM, but there is additional complexity because some operations target a larger "erase block" rather than an individual byte.

                    Some embedded platforms present a raw interface to the flash memory and require the host operating system to provide support for bad blocks and wear-levelling. These would be specified in "MiB" along with a certain allowable percentage of bad blocks.

                    However, the more familiar approach (e.g. in a SD card) is to include an embedded microcontroller that presents a logical block interface to the host. This controller skips over the bad blocks, and also needs to use some of the good blocks to keep track of the logical-to-physical block mapping. Here it makes more sense to use SI notation.

                    I just checked an "8 GB" microSD card and found that it presents a capacity of 7969177600 bytes to the OS (before partitioning). So 0.4% of the rated capacity is not available to me. This is consistent with the typical fine print on the package, e.g. "Some of the listed capacity is used for formatting and other functions, and thus is not available for data storage" (from Sandisk's website). If the manufacturer had sold it as an "8 GiB" card I would be more upset because that would represent a 7.3% capacity loss.

                • Re:Powers of 2 (Score:5, Insightful)

                  by mdielmann (514750) on Tuesday January 27, 2009 @02:56PM (#26627701) Homepage Journal

                  Um, yeah, except that just about everything is stored on powers of two. This is as absurd as if hot dogs were sold in packages of 8 (or 1024) and buns were sold in packages of 10 (or 1000). AND they used the same term to describe both, until it got to the point where they could sell significantly less than was expected while using VERY small print to notify us of this change in wording.
                  There is absolutely NO reason to use base 10 numbering for computer memory of any kind, except that it allows manufacturers to use bigger numbers while selling less. The only mitigating factor is that now that they all do it, at least we're back to comparing apples to apples.

            • Re:Powers of 2 (Score:4, Insightful)

              by sexconker (1179573) on Tuesday January 27, 2009 @01:27PM (#26626153)

              Let me explain this is detailed, complicated-for-you, terms.

              Exponents are useful for counting possible combinations. Computers are logically binary and quantum. When dealing with storage, we use 1024, because it represents the number of possible configurations of a 10-bit sequence.

              2^10 was chosen for convenience - it was close to 1000, which people are used to working with, and it provided a good separation between major units.

              1000 was chosen by SI for reasons just as arbitrary, namely providing a good spacing. We have scalar units of 10 (decimeter, decameter, for example), but no one ever says "Go down the road 1.2 deca kilometers".

              SI units (major units based on a factor 1000, with shitty units based on 10 for completeness) are for measuring.

              Computery units, (major based on a factor of 1024, with minor units based on 2 as the basis), are for counting.

              This is why clock speeds use 1000, not 1024. Clock speeds are traditionally measured, and not counted, and they do not operate on a binary quantum system.

              This is why data storage is SUPPOSED to be described using 1024, while data transfer is described using 1000.

              If you want to get down to it, all SI units are retarded, since the universe is quantum (it is). All measurements are merely inaccurate tools of convenience, and everything should be counted in universal quantums of space (Planck Length? I doubt it, unless it really is tortoises all the way down), time, etc.

              To sum it up - SI is not right because it's "official". SI is WRONG for computer science. And if the universe is quantum, SI is technically wrong for everything. Calculus, too.

              • Re:Powers of 2 (Score:5, Insightful)

                by Al Dimond (792444) on Tuesday January 27, 2009 @01:54PM (#26626697) Journal

                SI might be wrong for computer science, but SI prefixes have standard meanings. If we want prefixes that work better for computing (which we may well), then making new ones, just to be clear, is a good idea. Then if SI is wrong you don't have to use it, and you don't confuse everyone by using its terminology to mean something slightly different (which is much worse than using it to mean something very different).

                Anyway, the power-of-two units make some calculations easier and many harder. Just because an N-bit MUX has 2^N inputs doesn't mean they'll all be connected to something. You have 4 384-byte memory modules, quick, how many kB? Um, what's 384/1024? 3/8 maybe? Having to mess with mutliplying/dividing by 1024 in the middle of back-of-the-napkin calculations where not every number is a simple power of 2 (even if many of them have lots of 0s at the end in binary, like 384 does) actually does suck unless you just give in and learn your multiplication tables in hex (if I was still doing driver programming I probably would have done just that).

              • Re:Powers of 2 (Score:4, Insightful)

                by RzUpAnmsCwrds (262647) on Tuesday January 27, 2009 @03:27PM (#26628139)

                To sum it up - SI is not right because it's "official". SI is WRONG for computer science. And if the universe is quantum, SI is technically wrong for everything. Calculus, too.

                No one gives a shit whether your measurement system is 'correct', as long as it's consistent. SI is VERY consistent for a system that spans so many fields. That's why it's better than the US customary system.

                This is why data storage is SUPPOSED to be described using 1024, while data transfer is described using 1000.

                There's nothing inherent to today's storage technologies that requires power-of-two capacities. We're not even using a fraction of the address space we already have, so sticking to a power-of-two size doesn't have any real benefits.

                SI is WRONG for computer science.

                Oh, so Computer Science is so important that we get to invent our own units, and use the same names as established SI units? Please. If you want to use binary units because they are convenient, go ahead and do so. But DON'T call them "tera", "giga", or "mega"; these terms already have SPECIFIC meanings and you can't just hijack them.

            • Re: (Score:3, Insightful)

              by erroneus (253617)

              Okay, I suppose you are correct in your view. From now on, a foot is ten inches because a unit of measure not based on tens is inconvenient. After all, the metric system works exactly this way. Also, there will be ten hours per day, ten days in a week and ten weeks in a month... and of course ten months in a year which, for me, makes "December" far less confusing since the Dec in December means ten in the first place.

              Yes, that is sarcasm. To me, a unit of measure, no matter how inconvenient, is a unit o

    • The capacity hasn't changed -- only their definition of a terabyte.
    • Re:Powers of 2 (Score:4, Informative)

      by corsec67 (627446) on Tuesday January 27, 2009 @12:36PM (#26625153) Homepage Journal

      You mean 1800 Gibibytes?

      • Re: (Score:3, Interesting)

        by JesseMcDonald (536341)

        No, I'm quite sure the OP meant 1800 gigabytes, or about 15.46 terabits.

        Established convention is that bytes are measured in binary (powers of 1024), and bits in decimal (powers of 1000). There's no need to introduce ridiculous-sounding terms like "gibibytes".

        (Incidentally, I suspect there would be a lot less resistance to these newfangled units if they'd had the sense to pick names people could be expected to say with a straight face...)

      • by Just Some Guy (3352) <kirk+slashdot@strauser.com> on Tuesday January 27, 2009 @02:11PM (#26626985) Homepage Journal

        You mean 1800 Gibibytes?

        I will never, ever, in my entire life, even once mean "gibibytes".

    • Re: (Score:3, Funny)

      by fprintf (82740)

      The funny thing is both of my home computers have drives smaller than the missing 200GB from this 2TB drive. I really need to upgrade soon...

    • Personally, I'm glad the industry is moving toward using standard international units. This is 2GB and 1800 GiB.

      The silly thing about the situation is that some people prefer to use the wrong units for no good reason other than tradition.

  • That was quick. (Score:5, Insightful)

    by jcr (53032) <jcr.mac@com> on Tuesday January 27, 2009 @12:19PM (#26624791) Journal

    Wasn't it only about a year ago that 1TB drives hit the market?

    -jcr

  • by Coraon (1080675) on Tuesday January 27, 2009 @12:19PM (#26624799)
    I was worried I would have to start deleting from my *cough* adult movie collection *cough* to make more room
  • backups (Score:5, Interesting)

    by Reality Master 201 (578873) on Tuesday January 27, 2009 @12:23PM (#26624863) Journal

    What the hell do you do to back up your 2TB drive?

    That much storage in a single unit seems kind of dangerous.

    • Re:backups (Score:5, Insightful)

      by Moridineas (213502) on Tuesday January 27, 2009 @12:25PM (#26624913) Journal

      What the hell do you do to back up your 2TB drive?

      2 other 2TB drives?

      • Probably from the same manufacturer, with the same failure rates.

      • backups-Blowups. (Score:4, Insightful)

        by Ostracus (1354233) on Tuesday January 27, 2009 @12:28PM (#26624981) Journal

        Unless they're all the same model made in Thailand.

      • by AntEater (16627)

        Well, based on my experiences, I would strongly suggest that you purchase some non-Western Digital hard drives for your backups. That is, unless you like being on a first name basis with their technical support agents.

        • I've had worse luck with Seagate...

          But given that I'm dealing with small numbers of drives, I don't think there's any statistical significance to my experiences.

        • by nxtw (866177)

          Well, based on my experiences, I would strongly suggest that you purchase some non-Western Digital hard drives for your backups. That is, unless you like being on a first name basis with their technical support agents.

          I had a WD desktop drive show signs of failure a few months ago (SMART showed offline unreadable sectors.) I was able to get a replacement just by filling out a few forms on the web.
          Seagate's the same way, but they charge a nonrefundable fee for advance replacement (where they send you a repl

    • by Greyfox (87712)
      Another 2TB drive. They're cheap enough to keep a spare around. If you're paranoid about leaving it in the case you can pick up an external SATA or USB rig and only plug it on when you're running backups.
      • Re: (Score:3, Insightful)

        by Xemu (50595)

        Another 2TB drive. They're cheap enough to keep a spare around.

        The problem with that is of course that mirroring simply mirrors problems on the primary drive to the secondary drive. So you end up with two working drives with broken data on it.

        It's the data you want backed up, not the drive.

        • by Wdomburg (141264)

          A second drive doesn't necessarily mean mirroring.

        • by nizo (81281) *

          Though if your primary drive is spitting out bad data, it doesn't matter what backup media you are using.

    • by TheMiddleRoad (1153113) on Tuesday January 27, 2009 @12:37PM (#26625173)

      Every time a new, larger drive comes out, people say, "That much data in one drive is dangerous!"

      So here's what you do. Go buy ten 200GB drives. RAID them together. Who do you think will lose data, you, with ten times the possible failure points, or me with only one?

      Just back it up, biznatch!

      • by Reality Master 201 (578873) on Tuesday January 27, 2009 @12:40PM (#26625225) Journal

        My RAID setup would use drives from different manufacturers and production lots, and contain hot spares.

      • Re: (Score:3, Informative)

        by Ephemeriis (315124)

        Every time a new, larger drive comes out, people say, "That much data in one drive is dangerous!"

        So here's what you do. Go buy ten 200GB drives. RAID them together. Who do you think will lose data, you, with ten times the possible failure points, or me with only one?

        Just back it up, biznatch!

        Well, of course backups are the solution. And anyone with half a clue and some important data has nobody to blame but themselves if they don't have a backup.

        But if you've got 10x 200 GB HDDs, and one of them fails, you've only lost 200 GB. And in a RAID setup you might not even notice that single drive failure...which means you can easily slot in a new drive and never lose any data.

        While if you're running 1x 2 TB HDD, and that one drive fails, you're pretty much hosed. In this situation you'll be rebuild

      • by 4D6963 (933028)
        Ten times the possible failure points??? What the hell are you talking about, a RAID 0 array?
    • Re:backups (Score:5, Insightful)

      by timeOday (582209) on Tuesday January 27, 2009 @12:38PM (#26625185)

      That much storage in a single unit seems kind of dangerous.

      I never understood this argument. Say you have N drives each with capacity C/N (e.g. C=2TB, N=1 for this new drive, or C=500GB, N=4 as you prefer) and probability P of each drive failing in a given time interval. Your expected data loss is N*P*C/N, which is independent of N. So what's the gain from more drives?

      Heck, assume you don't want the hassle of multiple partitions so you use logical volume management to concatenate the drives (simulating the larger disk). Since any failure kills the whole thing, it's even worse - N*P*C.

      I guess maybe your are thinking of RAID5? But is this an enterprise-class hard drive? I'm not buying (or buying electricity for) 3x 1TB drives instead of 1x 2TB drive just to protect my PVR recordings. And since RAID (regardless of level) is not a backup, if the data is any more important than PVR recordings, you still need backups with or without RAID. So all RAID5 gives you is decreased time to recover from a broken drive, by making you buy a spare up front. Obviously decreased downtime is critical for an important server, but not for the vast majority of home PCs.

      • Re:backups (Score:4, Insightful)

        by ColdWetDog (752185) * on Tuesday January 27, 2009 @12:57PM (#26625523) Homepage
        Actually a multi terrabyte RAID 5 drive is a nice bit of the backup solution. No, it's not the be all and end all of backups. You still need separate completely off line and off site backups. But since modern RAID boxes can tell if a drive is bad, you get to look at the blinken light, go "oops", pull the drive and plug another one in. Wander off to Slashdot for a few hours and poof. Your data is back. No muss, no fuss. I like that part.

        You can never be too rich, too thin or have too many backups. At least I get the chance to do one out of three....
        • Re: (Score:3, Interesting)

          by nxtw (866177)

          Actually a multi terrabyte RAID 5 drive is a nice bit of the backup solution.

          RAID 5 gets increasingly dangerous as drive size increases. Going strictly by published unrecoverable read error rates (1 per 10^14 bits read on recent Seagate desktop drives), the chance of data loss during a rebuild can be very high - 48%, assuming a five-drive array of 1.5 TB drives with this failure rate.
          Of course, these figures don't mean that 10^-14 of all bits read will result in a failure. It also doesn't mean that an erro

        • Re:backups (Score:5, Informative)

          by bendodge (998616) <bendodge@b[ ]rog ... m ['sgp' in gap]> on Tuesday January 27, 2009 @01:54PM (#26626691) Homepage Journal

          There's another problem. Take a look at this excellent article:
          http://blogs.zdnet.com/storage/?p=162 [zdnet.com]

          SATA drives are commonly specified with an unrecoverable read error rate (URE) of 10^14. Which means that once every 100,000,000,000,000 bits, the disk will very politely tell you that, so sorry, but I really, truly can't read that sector back to you.

          ...

          Disk drive capacities double every 18-24 months. We have 1 TB drives now, and in 2009 we'll have 2 TB drives.

          With a 7 drive RAID 5 disk failure, you'll have 6 remaining 2 TB drives. As the RAID controller is busily reading through those 6 disks to reconstruct the data from the failed drive, it is almost certain it will see an URE. So the read fails. And when that happens, you are one unhappy camper. The message "we can't read this RAID volume" travels up the chain of command until an error message is presented on the screen. 12 TB of your carefully protected - you thought! - data is gone. Oh, you didn't back it up to tape? Bummer!

      • If N=16, you lose one-sixteenth of your data. If N=1 you lose all of your data.

        You are right the first scenario is sixteen times more likely to happen, so mathematically there is no difference.

        For practical purposes I'd take the small dataloss...
    • Re: (Score:3, Funny)

      by ChienAndalu (1293930)

      Bittorrent?

    • by MightyYar (622222)

      I'll probably buy 2 when the price comes down a bit. I'll keep data that doesn't really need to be backed up on it, and then periodically clone it to the other drive. Things like my movie collection (have the originals), iMovie projects (have the original tapes), virtual drives. On 2TB, I could fit all of my 13-GB-each iMovie projects and all of my DVDs in whole. I currently archive the iMovie projects to DVD and use a shelf to hold the movies.

      My Mozy backup for everything else is just under 300GB and I'm o

    • 7 hours? (Score:4, Interesting)

      by mikeee (137160) on Tuesday January 27, 2009 @12:59PM (#26625593)

      It's worse than you think. Even if you have a place to back it up, the I/O rates on modern HDs aren't increasing nearly as fast as capacity. Reading at top speed, it would take almost 7 hours to pull all the data off this drive, even if you have someplace to put it. Similarly, if you're using it as part of a RAID set, it'll take that long to rebuild if you have a failure.

      Pretty soon the MTBF on these drives will be a significant fraction of (capacity)/(read rate); that will make for fun all around.

    • by DaHat (247651)

      Use a Windows Home Server [microsoft.com]?

    • by ceoyoyo (59147)

      Set up an FTP server with anonymous access to your 2 TB drive.

      Let's be honest: you don't have 2 TB worth of your own stuff. You've got 2 TB worth of porn and Bittorrented movies.

    • What the hell do you do to back up your 2TB drive?

      Can I use it as my backup server?

      I have an iMac with only a 500GB hard drive, so I figure a 2TB drive would store a lot of Time Machine differential backups. Of course, somewhere in there it becomes an archival server instead of just a backup server...

    • Mozy.com or Carbonite.com will back that up. Assuming just because you have a 2TB drive, you don't start out with 2TB of new data.

      Restores are another matter.

    • Re: (Score:3, Informative)

      by Trixter (9555)

      Simple: Buy two, and use one in an eSATA hard drive cradle/dock. Once a night, turn on the dock, back up the data, then turn it off.

  • Perfect (Score:5, Insightful)

    by timeOday (582209) on Tuesday January 27, 2009 @12:23PM (#26624873)
    Spindle-drives are inherently slow anyways, so I think the combination of a big, power-efficient drive (never mind the speed) for movies and an SSD drive for everything else is ideal.
  • Nice (Score:5, Interesting)

    by Anonymous Coward on Tuesday January 27, 2009 @12:23PM (#26624881)

    The cache on this drive is 8x larger than the capacity of my first hard drive.

  • by Anonymous Coward

    Two Terabytes should be enough for anybody

  • WD20? (Score:5, Funny)

    by argent (18001) <[moc.agnorat.6002.todhsals] [ta] [retep]> on Tuesday January 27, 2009 @12:26PM (#26624931) Homepage Journal

    It'll be so slick when the 4.0 TB WD40 comes out.

  • by jollyreaper (513215) on Tuesday January 27, 2009 @12:29PM (#26624989)

    Agent smith: What good is 2 terabytes of porn if you are unable to access it?
    Keanu: (glances worriedly at his zipper)
    agent smith: (palm to face, shakes head) The hard drive, you imbecile, the hard drive.

  • by auric_dude (610172) on Tuesday January 27, 2009 @12:32PM (#26625067)
    No thanks, looks and smells a bit fishy to me.
  • by TheMiddleRoad (1153113) on Tuesday January 27, 2009 @12:39PM (#26625219)

    The problem with a larger drive is I fill it quickly. Should I buy a 2TB drive and use it to backup my already full two 1TB drives, or should I just add storage? Oh, the agony!

    • by Ngarrang (1023425)

      You should buy (2) 15-disk arrays. One for active use, the second for backups. At 15 disks, how quickly could one fill 28TB of space?

      • Figuring 200GB a month of downloads (darn Comcast!) plus ripping DVDs and HDDVDs, I'd say a couple years. And since my wife would leave me for buying all those disks plus a case to handle them, and that our power bill would skyrocket, and that the noise would be obnoxious, I'd have plenty of time to devote to ripping content! ;)

  • by jedidiah (1196) on Tuesday January 27, 2009 @12:47PM (#26625361) Homepage

    It will be nice to have someone besides Seagate in this space.
    Perhaps they will be motivated to get their act together. If they
    don't those of us that buy these kinds of drives at least have an
    alternate vendor now.

  • The 1.5TB Seagate drives have only been available from a small
    number of online vendors for a short while now and just now
    became available from brick+mortar outlets like BestBuy.

    Any idea when these drives will hit a shelf at Frys?

    The new retail packaging is relatively tiny BTW. You could blink and miss the new boxes.

  • 32MB On Disk Cache (Score:4, Interesting)

    by 3p1ph4ny (835701) on Tuesday January 27, 2009 @01:11PM (#26625813) Homepage

    I was thinking about this the other day, but, does the 32MB on disk cache really matter?

    Think of it this way: the Linux kernel does disk caching with my free RAM (which I generally have more than 32MB of) according to some reasonable locality scheme (LRU or something).

    If the HDD does the same caching according to nearly the same principles, won't the data on the disk cache nearly always be a subset of the disk cached in RAM? Meaning: doesn't the disk cache have no effect whatsoever?

    I'm genuinely interested in an answer to this question, even if it is a little OT. Please burn a little karma for me :)

    • by drsmithy (35869) <drsmithy@gmailSLACKWARE.com minus distro> on Tuesday January 27, 2009 @01:24PM (#26626083)

      If the HDD does the same caching according to nearly the same principles, won't the data on the disk cache nearly always be a subset of the disk cached in RAM? Meaning: doesn't the disk cache have no effect whatsoever?

      No, because the OS does not know about the physical layout of sectors on the disk and the HDD controller does. Therefore, it can reorder requests appropriately to maximise performance.

      Disabling the cache on a hard disk gives a massive performance hit, especially for writes. They become nearly an order of magnitude slower.

  • This hdd seems to be competing with the spinpoint f1 and the latest of seagate's 7200 RPM hdds. The kicker is this is a "green" series drive. It uses variable RPM technology. It actually spins at 5400 RPM quite often.
    I'm still not convinced going green on the HDD will save energy as it drops 10 watts on your total load. In an array of arrays, there may be savings though. Gamers, remember, your power supply/CPU/video card are the biggest culprits. Lower power will generally equate to lower hear and thus le
  • I read both TFA and Western Digital's press release [wdc.com]. There is not one actual number behind any of the claims of "low power". Guys, we do have ways of quantifying power consumption, you know.

    • by rthille (8526) <web-slashdot@@@rangat...org> on Tuesday January 27, 2009 @01:42PM (#26626425) Homepage Journal

      Well, you could click twice more, once on this (in the linked PR) http://wdc.com/en/products/Products.asp?DriveID=576 [wdc.com] and then on the "Specifications" tab (I hate web 2.0 shit like this where you can't properly link to content).

      Power Dissipation
              Read/Write 7.4 Watts
              Idle 4.0 Watts
              Standby 0.97 Watts
              Sleep 0.97 Watts

      For comparison, here are the number for the 1TB (32MB cache)
      Current Requirements
              Power Dissipation
              Read/Write 5.4 Watts
              Idle 2.8 Watts
              Standby 0.40 Watts
              Sleep 0.40 Watts

      I don't understand why Standby/Sleep power use more than doubled... As for the Active, I assume that's due to spinning 2x the platters and added processing power to be able to process the data coming off those platters 2x the speed.

  • by Tatsh (893946) on Tuesday January 27, 2009 @01:45PM (#26626489)

    I do not think I will be buying this one, or another WD. It is really hard to witness so many dead hard drives (including many DOA) and have your own experiences with their hard drives that just die so quickly. And another thing, why is every WD so damn big? They squeeze into every slot you put them into, not just slide in nicely like any Seagate (or most other brands). This goes for desktop and laptop. No wonder they are making their own external drives. Generic ones may not even fit their drives.

    I have had much success with Seagate (lasts 5 years or more) and Hitachi (louder than most HDDs but they last). I do not know the warranty of WD, but the warranty for both Seagate and Hitachi are great (especially the Seagate one).

    I am sure some people have luck, but after 2 dead hard drives (and many DOAs at a shop I worked at) and physical size problems, I will probably never give WD another chance, no matter what the price.

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