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Formatted space compared to adv. space. RRS feed

  • Question

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    All,

     

    I know when you format a drive you loose space, but is there a way to tell exactly how much?  I have a 750GB drive, how much is that formatted?

     

     

    Thursday, February 21, 2008 4:15 AM

Answers

  • It's worse than that Sam - they quote 1 GB as 1,000,000,000 bytes.  But since computers are slightly dependent on base 2  1 GB is actually 1073741824 bytes, hence 750GB (disk) = 698 (real) GB.

     

    Then there is the NTFS overhead but that is relatively small in comparison to the drive size.

    Thursday, February 21, 2008 10:01 AM

All replies

  • It's more about hard drive manufacturers lying to their customers. Most drive manufactures measure 1 GB as 1000 MB (for marketing purposes, the excuse they give is that people "understand" it easier that way), which is incorrect. 1 GB = 1024 MB.

     

    So if your drive is labelled in this way, you're looking at just over 732 "real" GBs once Windows formats it. 

     

    Thursday, February 21, 2008 9:45 AM
    Moderator
  • It's worse than that Sam - they quote 1 GB as 1,000,000,000 bytes.  But since computers are slightly dependent on base 2  1 GB is actually 1073741824 bytes, hence 750GB (disk) = 698 (real) GB.

     

    Then there is the NTFS overhead but that is relatively small in comparison to the drive size.

    Thursday, February 21, 2008 10:01 AM
  • <beat dead horse>
    Nobody's lying.  Hard drives have always had their size advertised (and spec'ed) in decimal (base-10) math (i.e. 1 byte = 10 bits; 1 KB = 1000 B; ... 1GB = 1  billion bytes.)  This happens to be a telecom standard.
    However, Windows (along with every other OS on the planet) calculates HDD size in binary (base-2) math (i.e. 1 byte =2^10 bits; 1 KB = 2^10 B; .. 1GB = 2^30 bytes.)  This happens to be a computer-sciences standard.
    </beat dead horse>

    To answer the question, Jimbo has the math right.  750 base-10 GB =~ 698 base-2 GB.

    Friday, February 22, 2008 2:44 AM