Help me understand how much capacity I have

Discussion in 'iPod' started by BBQ BOY, Apr 13, 2011.

  1. BBQ BOY macrumors regular

    Feb 23, 2010
    I have my 80GB iPod hooked up to iTunes. It says 56.6GB free but then says Capacity 74.37GB. Ho much space have I used?
    I am trying to buy an iPad. With that being said I am wondering if I can just buy the 16GB iPad.
  2. drsoong macrumors member

    Mar 24, 2008
    Hard disk manufacturers found it to be an original marketing idea to call 10^9 Bytes a GB or GiB, while in a traditional computer science sense which is based on binary and hence a GigaByte is 1024 x 1024 x 1024 = 2^30 Bytes.

    This explains why the capacity shown is 74.37GB and not 80GB.*

    Now "capacity" means how much it is capable of storing and if you subtract from how much there is still "free", 56.6GB as you said, you know how much space your music takes up, right?

    *With Snow Leopard Apple also adapted the GiB view on storage capacity, which is why on Snow Leopard a "80GB HD" (as sold by the manufacturer) shows a capacity of 80GB. I therefore suppose you were not using Snow Leopard when looking at your iPod's drive?
  3. SidBala, Apr 14, 2011
    Last edited: Apr 14, 2011

    SidBala macrumors 6502a

    Jun 27, 2010
    You are probably using up around 17-18 gigs. But don't assume that just by shaving off 2 gigs you will be okay with a 16GB iPad.

    The '16GB' iPad only has like 12 or 14 GiB of usable space, IIRC.
  4. Chundles macrumors G4


    Jul 4, 2005
    80GB = 80,000,000,000 Bytes

    80,000,000,000/1024 = 78,125,000 Kibibytes (KiB)

    78,125,000/1024 = 76,293.945 Mebibytes (MiB)

    76,293.945/1024 = 74.505 Gibibytes

    Computers incorrectly report GiB (IEC Binary 2^30) as GB (SI 10^9). HDD manufacturers have it right, a Gigabyte DOES equal a billion bytes.

    The confusion comes from assigning the term "Kilobyte" to a unit of 1024 bytes. This is WRONG. Kilo is an SI prefix that can ONLY mean one thousand of something.

    If we'd settled on using binary prefixes back in the day or, like Snow Leopard does now, reported capacities correctly then all this hassle would be a thing of the past.
  5. viggen61 macrumors 6502

    Jul 24, 2002
    New Jersey
    Well, Capacity is the maximum # of units (bytes, liters, pounds, widgets) that something can hold, and "free" means space available for more of the units, so...

    73.37GB - 56.6GB = 16.77GB used

    If you want to put ALL of that stuff that you have in your iPod on an iPad, you'll need at least the 32GB iPad. Of course, there's no rule saying that you must sync everything you have on the iPod to the iPad, and you still have an 80GB iPod to tote your music around on, so maybe you can get by with the 16GB iPad.

  6. BBQ BOY thread starter macrumors regular

    Feb 23, 2010
    If this iPad were for me then without a doubt I would buy the 64GB. This will be used for my children so yes you are correct that I do not need all of the info on it that's on my iPod. Actually I would not put the music nor a lot of the movies on the iPad that are on the iPod.
    The main function of the iPad would be for educational purposes and some kids movies for family trips.

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