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MiB vs MB; GiB vs GB and IEEE 1541

Tech Report has a poll going – Poll: Gigabytes vs. gibibytes.

You may not know it, but the world of technology is split into two camps right now. For one camp, megabytes, gigabytes, and terabytes are all powers of 10. Hard drive makers are part of that clique, as is Apple, at least since the release of Mac OS X 10.6 Snow Leopard. For the other camp—the traditionalists, if you will—those same units are powers of two. On that side of the ring, we find Microsoft, memory vendors, and just about anyone who doesn’t know the difference.

The issue is whether you are counting in base 2 like a computer or base 10 like a human. Engineering has always uses thousands as a convenient grouping so measures are reflected with kilo, mega, and giga prefixes to indicate thousands, millions, or billions. It is convenient, yet maybe a bit deceiving, that 2 to the 10th power is very close to ten to the third power. So ten with a 3, 6, or 9 exponent is sorta’ like 2 with a 10, 20, and 30 exponent.

This really wasn’t an issue when data storage was measured by thousands. Whether a thousand was 1024 or 1000 didn’t make much difference. When storage went up to a million, the difference between power of 2 round off and base ten became that of 1,048,576 or 1,000,000 and when talking billions 1,073,741,824 versus 1,000,000,000. That means an error of 2.4% for thousands, 4.9% for millions, or 7.4% for billions. A couple of percent is a ‘reasonable’ error but getting towards 5% or more can be an issue. For terabytes, the error starts getting close to ten percent.

Another factor is that devices like hard drives are becoming less connected to binary addressing schemes like other memory devices. Hard drives are also the most common (cheapest) for terabyte storage, too, and where people are most likely to being trying to purchase storage space rather than addressing convenience (i.e. speed). So sales efforts have to be a bit less deceiving and that may be why a terabyte drive is advertised as TiB so a buyer knows he’s getting a 1,000,000,000,000 rather than 1,099,511,627,776 bytes of storage.

So if you’re use to MB and GB and see something like MiB or GiB, you’ll know someone is following standards and trying to be honest with you.

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