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Hard Drive Capacity Confusion, Lucidly Explained
mrklin writes "James Wiebe of wiebetech.com has written a clear example of how hard drive capacity is calculated (PDF file) by hard drive manufacturers (base 10) and OS (base 2). He failed to name how the capacity should be described, though."
Ah, and therein lay the crux of the matter. The problem is that *everywhere else* kilo-, mega-, etc. prefix units (to stop the megapolis argument) they denote powers of 10. A megavolt is a million volts. A kilometer is 1000 meters. A gigahertz is a billion hertz. Only in computer science have people redefined the units to refer to anything other than powers of 10. *That* is what the debate revolves around, and that is what is IMO the mistake of people early on. The solution is to make kilobytes officially be 1000 bytes (as the IEC has) and use a different unit for the powers of two.
The author at one point in the article says that operating systems have historically not documented how size is counted. Like the engineers at a drive manufacturing company aren't smart enough to know that if you calculate a kilobyte in base 2 you are going to calculate a megabyte, or gigabyte in base 2.
Yes if you are smarter then your average computer user, which is to say smarter then a really dumb rock you should know that what's reported on a drive is not the actuall size.
It still hacks me off. It's like a soda manufacturer deciding it's ok to redefine an ounce so that they can claim that their drink is larger then it is or just use a smaller container and claim it's still the same size.
Does it matter, yes and it will matter more as storage capacity increases.
If you use a computer it does all calculations in binary, it only makes sense for the capacity of the drive to be calculated in binary.
Environmentalists are their own worst enemy. ~tricklenews.com
Like the engineers at a drive manufacturing company aren't smart enough to know that if you calculate a kilobyte in base 2 you are going to calculate a megabyte, or gigabyte in base 2.
That's where the standard agrument fails, because mega, kilo, giga, terra, et al are base 10 prefixes not base 2.
Your hair look like poop, Bob! - Wanker.
This is a big issue for those who use RAID arrays based on intercahngeable hard drives. This is a common practice among large corporations, and drive manufacturers' nonstandard descriptions of sizes make it very difficult to mix manufacturers within an array.
Buying from company A gives you 120GB=120 billion bytes, and buying from B gives you 120GB=128,762,169,664 bytes. If we have an array of 10 disks at the larger size and swap one out for the smaller size, the disks cannot be treated as interchangeable anymore, and the array loses much of its efficiency, or is forced to waste the extra space on the larger drives.
The bottom line is that this costs money. Companies are locked into using one supplier and must pass up opportunities for good deals. The lack of flexibility and occasional screw ups by interns who don't check which drive is which uses up the IT department's time.
Nobody really cares whether a GB is 1 billion or a funny number that comes from base 2, but a lot of people with a lot of money care whether 1 GB from company A equals 1 GB from company B. One of these days the industry will have to standardize.
It's just as bad as monitor sizes-they measure those at funny angles and have different sized black margins around the viewable area. Just a couple months ago a manager here ordered a new 19 inch monitor and was so annoyed by the margins that he sent it back to be replaced. We gave him an old, lower quality monitor with the settings adjusted to minimize the margin. Some guy in IT took the new one home with him, and wrote it off as trashed defective equipment.