Snow Leopard Reports Hard Drive Capacity Correctly (In Base 10)

Snow Leopard Reports Hard Drive Capacity Correctly (In Base 10)
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ZDNet reports that Snow Leopard has changed the way it calculates disk capacity from earlier versions of OS X: now it’s actually accurate, and you can better judge when a disk is really, actually full.

When it’s running Snow Leopard, your Mac shows you the same gigabyte count on your drives as now generally appears on the manufacturer’s box, calculated in base 10, and not in base 2, which is what Leopard, all earlier versions of OS X and all current and earlier versions of Windows uses. This Apple knowledge base article explains:

A 200 GB drive shows 200 GB capacity (for example, if you select the hard drive’s icon and choose Get Info from the Finder’s File menu, then look at the Capacity line). This means that, for example, if you upgrade from an earlier version of Mac OS X, your drive may show more capacity than in the earlier Mac OS X version.

My own tests confirm: a 4GB Cruzer thumb drive in my Snow Leopard Mac shows up with a capacity of 4.01GB. Leopard reports the same drive’s capacity as 3.74GB. (Click to enlarge the screenshot on the right.)

Kudos to Apple for leading the charge on this change for the better, which will reduce age-old consumer confusion and questions about why a drive seems smaller in the software than it says it is on the box. This change also raises two other interesting questions: Is this new “found space” part of the reason why Snow Leopard “saves” you disk space? (Because if it is, SL isn’t actually saving you anything–it’s just an accounting adjustment.) More importantly for the rest of the market: When will Windows follow suit?

Snow Leopard fixes disk capacity bug [ZDNet]


  • Well they are technically taking the correct side in the whole base two/base ten, kibibyte/kilobyte argument but certainly going against the flow of quite a few years of practice.
    Doing this does put them inline with hard drive manufacturers so at least people will be less confused, which is more important now as more and more of the easily confused are wanting to use computers 😛
    Personally, I see it as a dumbing down and probably a bit of a marketing gimmick. I prefer the base two system but I may be biased because I’m an Engineer.

  • Hi All,
    This is a mistake on Apples side.

    The hard drive industry had to follow suit when there competitors started calculating in base 10 thus giving them a size advantage.

    Mega,Giga, Tera -Bytes are all base 2 this is really fudging the reasults and total BS.

  • I prefer base 2 and will probably refer to 2KB as meaning 2048bytes till the day i die.

    The irony is mac users probably rarely buy a hard drive separately so they wouldn’t know anything about the base2 to base10 discrepancy issue.

  • Just another example of infantilization of the consumer.

    I can’t say my car has five wheels just because there is one in the boot.

    A drive with 1024GB is a 1TB drive – a drive that has 1000GB does not.

    Anyone who wants to force software or hardware to report it any other way is either Obsessive Compulsive or in advertising.

    People are sadly getting used to getting less for their money because the advertising tells them they are “really” getting more.

    You believe it because you want to not because it’s actually true.

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