Small Business Susan

So what’s after terabytes?

It seems like only yesterday that a 1 gig harddrive was HUGE….


Gah… 1 terabyte green Western Digital.  So remind me what’s after terabytes as I’m sure that’s next to be installed somewhere in the office.


  • #   douglash on 05.18.09 at 11:59 pm     

    Peta is next, here is a link to the si units

  • #   Andy Parkes on 05.19.09 at 2:55 am     

    Petabyte…then exabyte!


  • #   Richard on 05.19.09 at 5:17 am     

    Petabytes are a thousand terabytes.

  • #   Bryan Price on 05.19.09 at 7:56 am     


    Then it’s Exabyte (look out for that trademark!)



  • #   Rich Lusk on 05.19.09 at 8:01 am     

    Petabyte would be next and then exabyte. Interesting info on them at and And I thought terabytes were huge!!! Yikes!!!!!

  • #   Chris Knight on 05.19.09 at 8:11 am     

    10^9 giga G
    10^12 tera T
    10^15 peta P
    10^18 exa E

    and then you get into the silly SI prefixes.

    Skip the terabyte stores and simply grab a Petabox. Means you can park a shipping container in the parking lot and run some cables to it. Carpark whingers can be consoled with terabytes of user storage :-)

  • #   chris seiter on 05.19.09 at 9:23 am     

    Somehow I believe that the largest increment of drives will end up being called “Googlbytes”

  • #   Joe Raby on 05.19.09 at 10:20 am     

    It doesn’t matter. Whatever you buy, it’ll be less than 93% of the rated capacity because of the issue with hard drive manufacturers not calculating sizes the same as your OS.

    Ever wonder why we have hard drives in 320 and 750 GB’s? When you work out 93% of that, you end up with ~300 and 700GB hard drives respectively.

    When hard drive manufacturers start manufacturing drives en masse in multi-terabyte sizes, we’ll see a whopping 10% loss in drive space when they adjust their figures to an even 1 quadrillion bytes.

    For now, they are still using 1000 GB’s as a measurement, as you can see by the reported 931GB (that magic 93% figure).

    None of this factors in reserve sectors for defect relocation either, so it’ll still be even smaller.

  • #   Joe Raby on 05.19.09 at 10:22 am     

    If you’re using a WD drive for backup, don’t use a consumer drive. Shop for an RE drive instead.

    Or is this a WD RE2-GP model? There’s only one enterprise-class drive in “Green” with 1TB: WD1000FYPS

  • #   Douglash on 05.19.09 at 3:19 pm     

    joe so you have an issue with the Computer industry using the SI terms for memory.

    As you rightly point out. 10^3 <> 2^10

    Actual the drive manufacturers are stating it correctly they support 10^12 bytes of storage or 1 terabyte.

    It would be nice if computers used the new SI standard for base 2 kibi, mebi, etc etc to get away from the base 10 standard prefixes and get rid of this confusion.

    According to this standard one kilobyte (1 kB) is 1000 bytes, whereas one kibibyte (1 KiB) is 1024 bytes. Likewise mebi (Mi; 220), gibi (Gi; 230), tebi (Ti; 240), pebi (Pi; 250), exbi (Ei; 260), zebi (Zi; 270) and yobi (Yi; 280).


  • #   Joe Raby on 05.21.09 at 10:57 am     

    Actually, that’s not the way sectors work. Sectors will round up in binary terms, not decimal terms, so the excess is wasted.

    The OS is correct because of the way hard drives work.

    Hard drive manufacturers have effectively redefined the definition for computer terms because memory has always been recorded in base-2 even if the original definition of kilo, mega, giga, etc. aren’t correct. It’s already been accepted by memory and computer component manufacturers that use memory addresses. Only until hard drive manufacturers started getting into larger gigabyte sizes, did they redefine the accepted standard because now they’re just cheating customers.

    Case in point: If you buy 1GB of RAM, why is 1GB on a hard drive different?

    Answer: It shouldn’t be, but hard drive manufacturers have only [relatively] recently redefined the term for “giga”, as well as backported the definition to include “mega”, and “kilo”. Memory manufacturers haven’t changed. Accurate? No. But it doesn’t match the established standard either.