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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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Why are we seeing another article on this very issue?
Everyone understands HD manufacture's measuring systems. Failing that, we could just have billy fix up windows to overstate drive capacity to all windows users and they would never know any better.
No more Micro$oft bashing from me. Its like bashing at the special olympics.
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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I need to clear the 101th bit of that byte.
1 4m l33t. 1 4m d4 b0mb. 1 hax0red da 0xF49B5Cth byte 0f dat file.
0o1232 the number of the beast. (a music by Iron Maden)
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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.
"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. "
No, it does not. Eg. How many bytes are there in kilobyte? Anwer: 1024 not 1000. Thus we should not use the prefix 'kilo' as 2^10 because it is defined as 10^3. The SI-system works fine, we should not let people who still measures stuff with someones thumbs and feet ruin it.
Every time this issue comes up, and somebody proposes to abandon the use of K = 1024, people react saying that would be bad, because K = 1000 doesn't fit with power-of-2-based storage in computers.
./ religious wars' should be stopped. And I think it will: ifconfig, for example, already reports bytes transmitted/received as GiB, MiB, ...
That may very well be, but that's not the point. We can still use binary prefixes. But it doesn't make any sense to use the same prefix with different meanings. It makes perfect sense to use different prefixes, and to use different symbols for them. That way there is no confusion.
I never understood this really. CS is, of all fields, a field where it is important to be unambiguous. One byte wrong, or even one bit, and the computer doesn't understand it, or misunderstands it. Yet where it comes to defining storage units, we hijack the established 'kilo' and make it mean 1024 instead of 1000. Not even always: 1kbps is never 1024 bits per second, always 1000 bits per second.
I say, where it makes sense to use binary prefixes, let's do it. And let's be clear about it. The current 'Look ma, I'm using binary prefixes but I made them look exactly like the usual decimal prefixes so I can create confusion and
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Somehow I get the feeling that it's mostly Americans who refuse to accept that kilo=10^3, mega=10^6, giga=10^9. (Please read on before moderating as troll/fb.)
I guess that's because you aren't used to kilo, mega and giga, except to the (incorrect) power-of-2 definitions. To someone who lives pretty much anywhere else in the world (ie. where metric units are used), kilo has always been 10^3 and mega has always been 10^6. Well, except in most fields of CS (but not telecommunications or HDD capacity).
What's happening is that several different fields of science are slowly starting to overlap, and suddenly there's real confusion: for someone, kilo=10^3, for someone else it's 10^3 EXCEPT in some cases it's 2^10.
This source of confusion should be fixed now when it's still possible. It may seem to this audience that Computer Science == Life (and most of you probably don't need to think about data in terms of telecommunications) and therefore you think kilo=2^10 is standard, but for a huge majority of people it simply is not so.
Kilo has always been 1000 and will always be 1000. It's us the computer people who have made a mess of it, and we're also responsible for cleaning it up.
Mmmm, standards compliance....