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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."
In the grand scheme of things, drive capacity issues seem to revolve around lawyers more than consumers.
I wish that the major manufacturers would stop putting 1 BIG drive in the system, and put 2 normal sized ones in and MIRRORED.
As somebody who gets blasted by customers when they failed to do their backup, an out of the box, pre mirrored system would be far better for the consumer than properly labelling those lost 200 MB.
Sorry, that's my partially related rant for this evening.
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I think it's a little odd that he claimed that Hard drive makers have "Always" done this. I very specifically remember advertisements for hard drives being "One Billion Bytes" (with like a 14 point small print letting us know that it was indeed 1000000000 bytes). After that "billion bytes" became gigabytes and the font became smaller.
I've also heard that for some drive makers "gigabyte" means 1^20*10^3 (i.e. one thousand megabytes) and things like that.
autopr0n is like, down and stuff.
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.
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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.
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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.
I have to agree here. I've been using computers since the early 80's and the "kilo" or "mega" notation was well understood then to be an approximation, at least in my circles, to their decimal prefix equivalents.
... use it; point out to the rest of the world that MB is inaccurate and should mean 1000*1000 bytes, that MiB in fact *means* 1024*1024 bytes and this will solve our confusions within a generation.
"A kilobyte in a computer is 1024 bytes only because in base-2 it is simpler to count in 1024's than in 1000's"
That said, and everyone learned that back when people had to learn about computers (instead of growing up with them), this approximation is *still* just an approximation.
Just because you grew up thinking a kilo meant 1024 because you're in a non-metric country doesn't mean a kilo means 1024. It means your predecesors didn't bother using a different name for a different number (back when "the world will never need more than maybe 10 computers").
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