Case in point: I just bought a 320 GB hard drive to replace the 120 GB one in my computer.

What do I get when I plug it in? My computer tells me it can hold 297 GB. For those keeping score, 297 is less than 320.

In what bizarro universe does 297=320?

What about that 500 GB external hard drive I got last month? Nope, 465.

I love this wonderful new world of broken math! I’m cutting my car payment and rent checks by 8-odd percent, post-haste!

Yes, I realize the technical cause of this: I know that a “bit” does not equal a “byte.” Thus, the formatted drive is not as large as advertised.

The nerds pipe in, “but it IS 500 GB… when it’s not formatted for use…” I know! That’s not an excuse, that’s mealy-mouthed technical gobbledy-gook. When your box says 500 GB in 72 pt bold slab-serif (I measured! I own a pica stick!), I think I could be forgiven for expecting it to hold 500 Giga-something-usefuls!

Do you remember that scene in Arrested Development where G.O.B. performs a magic trick that turns one hundred dollars into one hundred pennies? And everyone’s impressed merely because he threw around 100 shiny things? (OK, there were impressed because it’s an absurdist comedy, but let’s move on.) It’s like that: sure, you’ve got one hundred of something, but it’s not as useful as you were led to believe.

How long until we, as customers, finally call hard drive manufacturers on their lies? When everyone plugs in their first shiny 1000 GB drive to discover it only holds 920? That’s a entire placeholder digit you’ve been robbed of!

It’s a set percentage that you’re losing every time, so it’s only going to keep looking worse as drives get larger, gang.

(Aside: why, after 30 years, do we still not have one single disk standard – hard drive, floppy, CD, flash, or otherwise – that works flawlessly on both a Mac and a Windows PC? Did someone not think that’d be useful some day?)

Is there any other product that can get away with this? Boxes of cereal and bags of chips come to mind, with their “Contents may have settled” (read: the bag is half empty) warnings.

Of course, this will never change. The first manufacturer that puts the true useful size of their hard drives on the box will go bankrupt. After all, who would buy a 465 GB drive off the shelf when the one right next to it claims it has 500 GB, even though they’re truly equivalent? It’s the same reason hotels, telecommunication companies, and airlines (and, well, every business) advertise a low price and then kill you with the fees. It’s all about getting people in the door, then gutting them.

Am I off my rocker? Is this not a big deal? Are there other products that instantly become 8% less useful as soon as you want to use them? (Insurance co-pays? You’ve got to pay a set percentage of the costs before insurance will pay the rest?)

Another aside: I feel a little remorseful about using a picture of a Seagate drive box, because, discounting the expected capacity lie, their packaging is refreshing and, frankly, delightful. Scan their boxes when you’re at the store next time. And check out their instruction manual:

Update

October 20, 2009: Interesting… when you update to OS X Snow Leopard (10.6), hard drives now show their “advertised” capacity. The 160GB hard drive in my macbook now says that it’s 159.96GB.

Now, are they lying? Like, does the hard drive fill up just as fast? I’m not sure what voodoo they’re working behind the scenes, but, golly, it feels better.

One weird part: when you plug in an iPod or an iPhone, you don’t see the advertised capacity. Why would they show you the nice round numbers for any old hard drive, but not on their marquee products?