New iMac w/ 320 GB HD shows only 297GB

Discussion in 'macOS' started by Halcyon, Nov 21, 2007.

  1. Halcyon macrumors 6502

    Sep 21, 2006
    Got my new 20" C2D iMac with a 320 GB hard disk...but when I check its capacity it says that it is about 297 GB and that 10 GB are already in used (system and few factory installed software).

    Where are the other 23 GB of disk space?
  2. chriswheat macrumors regular

    Jun 26, 2007
    Basically, when they say 320 GB they mean, 320,000,000,000 bytes...

    When in reality, 320 GB is actually 343,597,383,680 bytes.

    So if you convert 320,000,000,000 bytes into gigabytes, using the actual 1024 bytes per KB, 1024 KB per MB and 1024 MB per GB, you get 298.02 GB.

    This is an industry standard way of representing hard drive matter how corrupt it seems.
  3. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    Apple used to have that explanation around, now they just say "1GB is eqaul to x, formatted capacity may be less"
  4. chriswheat macrumors regular

    Jun 26, 2007
    I did a quick google search for a better explanation of this phenomenon:

  5. iEdd macrumors 68000


    Aug 8, 2005
    It's not really corrupt, but a little sneaky. They did say 320GB, NOT 320GiB.

    Wikipedia says:
    GB = Gigabyte, GiB = Gibibyte (a "true" gigabyte")
    1 Gigabyte = 1000 Megabytes = 1000000 kilobytes = etc
    1 Gibibyte = 1024 Megabytes = etc

    Apple dictionary says:
    1 Gigabyte = 1024 Megabytes

    So uh... I think the GiB notation was introduced to avoid confusion between 1000 and 1024 xs to a y, but instead just increased confusion. :eek:

    Now if someone says "I have 1GB", it can mean either. Do flash drives use TRUE gigabytes (ie. GiB)? I'd imagine they would, as RAM and flash memory increases by powers of 2.
  6. Halcyon thread starter macrumors 6502

    Sep 21, 2006
  7. tamvly macrumors 6502a


    Nov 11, 2007
    Actually, the stated capacity of a hard disk drive by manufacturers is the "unformatted" capacity of that disk. Formatting the disk into sectors reduces the effective capacity of the drive, because of the small gaps required between each sector. Full track blocking (one sector per track) is almost never used these days. Hard disks are composed of cylinders (the number of platters) and tracks (like the tracks on a vinyl LP only they are concentric) and, finally, sectors..

    A gigabyte is 1024 x 1024 x 1024 bytes, or 1,073,741,824 bytes. So a 320GB disk is actually 343,597,383,680 bytes.

    The reduction in capacity is simply, once again, the result of formatting.
  8. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    They note, "1GB = 1 billion bytes; actual formatted capacity less."

    They just don't tell you that "actual formatted capacity less" means about 7% less.
  9. MacBram macrumors regular

    Jan 28, 2002
    Zeeland, Nederland
    Not really, as noted above 320 x 1024 x 1024 x 1024 =343 "GB"

    Since 320 is the nice round marketing number given that everyone uses, it is evident they are using the 1000 base method of figuring size.

    This means, as far as the computer is concerned, the capacity is 298 GB using 1024.

    Therefore, 297 is only losing 1GB for formatting.
  10. cjcooper macrumors newbie

    Nov 6, 2008
    Was there a successful lawsuit against Seagate for doing just that? Simple because the industry has a standard formula for calculating a hard drive's size and not doing that was considered false advertising? I wonder how much money I could get from Apple now?

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