Kibibyte and mebibyte - WTF?

[Stonent]

Too many people complained that their 500GB drives were only 488GB so now they tend to specify in both on the boxes.

[dfmischler]

But there is no good reason to use binary prefixes for disk sizes.

Agreed.

These units make the speaker sound like a gibbering idiot. 

So don't say them.  If you say, "1 gig ethernet" nobody is confused (decimal).  If you say, "That computer has 16 gigs of RAM" everybody should assume that is 16GiB: 16*1024*1024*1024.  Disk drive sizes are now generally assumed to be decimal.  The most ambiguous case is for a file, but as far as I know all operating systems report binary sizes.  So for, "This file is 15 meg" everybody should realize that is 15MiB: 15*1024*1024.  And they can ask you if they are in doubt.

[c4757p]

There is no such thing as a "formatted size". Your 500 GB hard drive holds 500 GB exactly (once you define what a GB is). The fact that the operating system puts tables of contents into it is no fault of the hard drive (and will vary from system to system depending on configuration, anyway, so it's futile to list). Trying to list a "formatted size" of a hard drive is like trying to list a "printed size" of a piece of paper, accounting for margins.

The overhead is actually quite predictable given a certain disk size and file system. And in particular, what formatted size usually refers to in this context is the advertised size on the packaging. Many manufacturers print both the total and formatted size on the packaging, because this is required by consumer protection laws in some places. Hopefully they have enough quality control to predict the formatted size of the particular drives that they are shipping.

The available space on a piece of paper is quite predictable as well, considering most word processing software uses the same default margin sizes, but we've decided as a society that people aren't so brain-dead as to not understand that the margins will use a bit of the paper. Nobody is enough of a dumbass to come into a store furious that he could only print  6.5x9 inches on his 8.5x11-inch paper. How about we stop treating computer users like kindergartners?

[baljemmett]

Too many people complained that their 500GB drives were only 488MB so now they tend to specify in both on the boxes.

To be fair, I'd be pretty pissed off in that case too.  A thousand-fold discrepancy is pretty harsh, regardless of whether that's a decimal or a binary thousand

[sync]

The most ambiguous case is for a file, but as far as I know all operating systems report binary sizes.  So for, "This file is 15 meg" everybody should realize that is 15MiB: 15*1024*1024.  And they can ask you if they are in doubt.

And that for a value which has a granularity of 1 byte. It's just idiotic to use binary prefixes for file sizes. IFIAK Apple has changed to decimal prefixes.

[alm]

Clearly both base 2 and base 10 prefixes are commonly used for bytes, so it makes sense to distinguish them if we want to specify numbers with less than 10% uncertainty. Since base 10 prefixes pre-date the binary prefixes by about a century and are common both in CS and in other engineering disciplines, I think it would make sense to change the base 2 prefixes. If you think 'kibibytes' sounds stupid, feel free to convince the IEC to change the standard, pronounce it as 'kay eye bytes' or just avoid using base 2 prefixes all together. In the mean time, using TB and TiB will allow us to specify file and disk sizes without guesswork.

[Stonent]

Too many people complained that their 500GB drives were only 488MB so now they tend to specify in both on the boxes.

To be fair, I'd be pretty pissed off in that case too.  A thousand-fold discrepancy is pretty harsh, regardless of whether that's a decimal or a binary thousand

DERP! I was writing from my phone.

[johnwa]

I used to be quite against the new prefixes, seeing them accommodating the 'evil' HDD manufacturers in their attempts to short-change their customers. However, when you look into it, decimal prefixes are already used in some applications - a 28.8kbps modem = 28000 bits/second (forgetting about compression for now). And I realised that attempting to bend the metric prefixes into something that they are not would only result in confusion.

While the prefixes may sound a bit funny initially, their real value is that they allow unambiguous communication. If your meaning is 1048576 bytes, then the only way to communicate this unambiguously, other than writing it out in full, is to say 1MiB. It didn't really take long for me to go from hearing "mebibyte" and thinking "the speaker is a fool", to hearing it and thinking "the speaker values precision and clarity". A lot of programs are starting to use the new prefixes, so it seems that support for them is growing.

[rr100]

Speaking about greedy hard drive manufacturers: I think this part of the issue is exaggerated. Capacities were increasing all the time and still are, we just go the first 2TB "normal size" laptop drive (as in no thicker). Each time they go up one prefix they go up 1000 times (that's 100 000%) and we bicker about losing 2.4% ?! The difference is absolutely staggering, even across multiple prefixes and starting with 2 handicap (K and M) if you take from 10 MB to 3TB for example, that's 300 000 times increase (or if you want 30 000 000%). And we bicker about 10% for Ti vesus T.

The only part where it matters is consistency. If some manufacturer sold a 0.90TB drive and one a 1.0TB drive and have in fact the same capacity, now that would obviously suck for the manufacturer advertising 0.9.

[IanB]

While the prefixes may sound a bit funny initially, their real value is that they allow unambiguous communication.

Unfortunately, they don't succeed even in this. If you write 1 MB I still don't know whether you mean 1,048,576 bytes or 1,000,000 bytes. You still have to disambiguate by providing extra commentary ("1 MB, where M means one million decimal"). Without commentary, I would follow the normal practice of computer science and assume 1024 KB.

[Kjelt]

I would follow the normal practice of computer science and assume 1024 KB.

and what is a KB? Oh you mean kB. You are messing up the prefixes and expect other people to know what you mean? That is exactly why I think it is important to have the new binary prefixes. k means 1000, M means a million PERIOD. not 1024 or 1024*1024.

[westfw]

If you write 1 MB I still don't know whether you mean 1,048,576 bytes or 1,000,000 bytes.

Or maybe bits rather than bytes.

But it's hopeless; the binary "prefixes" are born out of laziness rather than any serious attempt at a meaningful prefix definition.  The roots are back in "Microsoft 4k basic", and "16k S100 memory boards"; there wasn't even a UNIT!

[rr100]

And this is precisely the thinking that created this mess ot of nothing.

[Kjelt]

Indeed, we have a perfect SI prefix system where k (not K  ) is a 1000 but when at a sudden we step into the CS dimension it needs to be something different because some dumbo's in the 70's made that mistake? Naaah mistakes are there to be corrected, people should adapt and move on.
Another generation and no-one will know about this fluke anymore.

[Fsck]

the more amusing thing is that *nix have *iB units
so apparently not all CS are weird

[dfmischler]

the more amusing thing is that *nix have *iB units

Well, some unix/linux systems are using *iB, in some places.  It has not fully penetrated yet.

... into the CS dimension it needs to be something different because some dumbo's in the 70's made that mistake?

"The use of K in the binary sense as in a "32K core" meaning 32×1024, or 32768, can be found as early as 1959."  I don't think it was a mistake to use "K" to mean 1024 in that context at that time.  Thank Dog they didn't use Latin prefixes (e.g. M for 1000, still on my natural gas bill as in "Mcf" for 1000 cubic feet).  That would have been a nightmare 

[amyk]

The only part where it matters is consistency. If some manufacturer sold a 0.90TB drive and one a 1.0TB drive and have in fact the same capacity, now that would obviously suck for the manufacturer advertising 0.9.

Another inconsistency that has always annoyed me about hard drive sizes is that they still need to be an integral multiple of 512 (2^9 aka 0.5K), the sector size. HDD manufacturers should start making "real-sized" drives; if they can make a "2TB" one that shows up as a little less than 1.86TB to the OS, they clearly have the technology to make a "1TB" one that contains exactly 2^40 = 1,099,511,627,776 bytes and shows up as 1.0TB. Then market it as a "REAL ONE TERABYTE" drive!

I still have a 16MB(!) USB drive that really does have a capacity of 16,777,216 bytes, or 8192 sectors.

Regarding communication speeds: again, I've only seen the binary sizes used in things like download progress bars and the like, so it's consistent with the rest of the presentation of sizes in the OS.

[rr100]

I very much prefer a 1.86 TiB drive to a hypothetical 1.0000000000000 TiB drive, thank you.

[sync]

The only part where it matters is consistency. If some manufacturer sold a 0.90TB drive and one a 1.0TB drive and have in fact the same capacity, now that would obviously suck for the manufacturer advertising 0.9.

Another inconsistency that has always annoyed me about hard drive sizes is that they still need to be an integral multiple of 512 (2^9 aka 0.5K), the sector size. HDD manufacturers should start making "real-sized" drives; if they can make a "2TB" one that shows up as a little less than 1.86TB to the OS, they clearly have the technology to make a "1TB" one that contains exactly 2^40 = 1,099,511,627,776 bytes and shows up as 1.0TB. Then market it as a "REAL ONE TERABYTE" drive!

It's not the hard drive manufactures fault. They are real 1 terabytes disks. It's the OS fault displaying the wrong value/ units.

[ovnr]

I've always used the traditional k/M/G prefixes (that is, 1024^n) for CS-related things. I'm not going to start using Mebibytes because it's fucking stupid, and the morons who decided it's a good idea are nuts.

If you cannot deal with the fact that some symbols and prefixes change meaning when changing technical fields, please find something else to do, like knitting. Because god help you if you ever start doing serious math or physics.

No, when I see people use kiBs and GiBs, I laugh at it, because you're a sheep going "baaa" at whatever you're told. Fucking stupid if you ask me.

[c4757p]

No, when I see people use kiBs and GiBs, I laugh at it, because you're a sheep going "baaa" at whatever you're told. Fucking stupid if you ask me.

Oh god. Another dude who thinks it's cool to call people sheep.

Sure, you might be a sheep doing whatever your told. Or, you think it's a good idea for the same reasons as the people who came up with it.

[Monkeh]

No, when I see people use kiBs and GiBs, I laugh at it, because you're a sheep going "baaa" at whatever you're told. Fucking stupid if you ask me.

Why thank you, would you care to insult us some more for being precise and sane?

[sync]

I've always used the traditional k/M/G prefixes (that is, 1024^n) for CS-related things. I'm not going to start using Mebibytes because it's fucking stupid, and the morons who decided it's a good idea are nuts.

Do you use 1024 based prefixes for bandwidths too?

[Kjelt]

I'm not going to start using Mebibytes because it's fucking stupid, and the morons who decided it's a good idea are nuts.
If you cannot deal with the fact that some symbols and prefixes change meaning when changing technical fields, please find something else to do, like knitting. Because god help you if you ever start doing serious math or physics.

It were the scientists and serious ones too who decided to introduce the binary prefixes because there was confusion in the world. And if you are a serious scientist and practitioner there is one thing you do not want and that is that something that has the same name has a different meaning depending on the context.
So give us a good example of serious mathematics or physics where the same prefix has a totally different value?

[IanB]

and what is a KB? Oh you mean kB

No, I mean KB. With an upper case K. As in 1024 bytes. As is the normal typographic convention for that quantity of bytes