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1 kilobyte is precisely 1000 bytes?

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Re: 1 kilobyte is precisely 1000 bytes?

#71

Post by dooglius »

card_zero wrote: post #59
Sophira wrote: post #30

Earlier quoted context omitted.

> Early diskettes always used 1000 Even worse, the 3.5" HD floppy disk format used a confusing combination of the two. Its true capacity (when formatted as FAT12) is 1,474,560 bytes. Divide that by 1024 and you get 1440KB; divide that by 1000 and you get the oft-quoted (and often printed on the disk itself) "1.44MB", which is inaccurate no matter how you look at it.

I'm not seeing evidence for a 1970s 1000-byte kilobyte. Wikipedia's floppy disk page mentions the IBM Diskette 1 at 242944 bytes (a multiple of 256), and then 5¼-inch disks at 368640 bytes and 1228800 bytes, both multiples of 1024. These are sector sizes. Nobody had a 1000-byte sector, I'll assert.

The wiki page agrees with parent, "The double-sided, high-density 1.44 MB (actually 1440 KiB = 1.41 MiB or 1.47 MB) disk drive, which would become the most popular, first shipped in 1986"

Re: 1 kilobyte is precisely 1000 bytes?

#72

Post by dgacmu »

nerdsniper wrote: post #9

Final edit: This ambiguity is documented at least back to 1984, by IBM, the pre-eminent computer company of the time. In 1972 IBM started selling the IBM 3333 magnetic disk drive. This product catalog [0] from 1979 shows them marketing the corresponding disks as "100 million bytes" or "200 million bytes" (3336 mdl 1 and 3336 mdl 11, respectively). By 1984, those same disks were marketed in the "IBM Input/Output Devic…

And networking - we've almost always used standard SI prefixes for, e.g., bandwidth. 1 gigabit per second == 1 * 10^9.

Which makes it really @#ing annoying when you have things like "I want to transmit 8 gigabytes (meaning gibibytes, 2*30) over a 1 gigabit/s link, how long will it take?". Welcome to every networking class in the 90s.

We should continue moving towards a world where 2*k prefixes have separate names and we use SI prefixes only for their precise base-10 meanings. The past is polluted but we hopefully have hundreds of years ahead of us to do things better.

Re: 1 kilobyte is precisely 1000 bytes?

#75

Post by theamk »

cedilla wrote: post #20
nerdsniper wrote: post #9

Final edit: This ambiguity is documented at least back to 1984, by IBM, the pre-eminent computer company of the time. In 1972 IBM started selling the IBM 3333 magnetic disk drive. This product catalog [0] from 1979 shows them marketing the corresponding disks as "100 million bytes" or "200 million bytes" (3336 mdl 1 and 3336 mdl 11, respectively). By 1984, those same disks were marketed in the "IBM Input/Output Devic…

You've got it exactly the wrong way around. And that with such great confidence! There was always a confusion about whether a kilobyte was 1000 or 1024 bytes. Early diskettes always used 1000, only when the 8 bit home computer era started was the 1024 convention firmly established. Before that it made no sense to talk about kilo as 1024. Earlier computers measured space in records and words, and I guess you can see h…

it's, way older in than the 1990's! In computering, "K" always meant 1024 at least from 1970's.

Example: in 1972, DEC PDP 11/40 handbook [0] said on first page: "16-bit word (two 8-bit bytes), direct addressing of 32K 16-bit words or 64K 8-bit bytes (K = 1024)". Same with Intel - in 1977 [1], they proudly said "Static 1K RAMs" on the first page.

[0] https://pdos.csail.mit.edu/6.828/2005/readings/pdp11-40.pdf

[1] https://deramp.com/downloads/mfe_archive/050-Component%20Spe...

Re: 1 kilobyte is precisely 1000 bytes?

#76

Post by stetrain »

pif wrote: post #53
marssaxman wrote: post #47

Earlier quoted context omitted.

That is a prescriptivist way of thinking about language, which is useful if you enjoy feeling righteous about correctness, but not so helpful for understanding how communication actually works. In reality-reality, "kilobyte" may mean either "1000 bytes" or "1024 bytes", depending on who is saying it, whom they are saying it to, and what they are saying it about. You are free to intend only one meaning in your own com…

I understand the usual meaning, but I use the correct meaning when precision is required.

How can there be both a "usual meaning" and a "correct meaning" when you assert that there is only one meaning and "There's no possible discussion over this fact."

You can say that one meaning is more correct than the other, but that doesn't vanish the other meaning from existence.

Re: 1 kilobyte is precisely 1000 bytes?

#78

Post by zephen »

cedilla wrote: post #20
nerdsniper wrote: post #9

Final edit: This ambiguity is documented at least back to 1984, by IBM, the pre-eminent computer company of the time. In 1972 IBM started selling the IBM 3333 magnetic disk drive. This product catalog [0] from 1979 shows them marketing the corresponding disks as "100 million bytes" or "200 million bytes" (3336 mdl 1 and 3336 mdl 11, respectively). By 1984, those same disks were marketed in the "IBM Input/Output Devic…

You've got it exactly the wrong way around. And that with such great confidence! There was always a confusion about whether a kilobyte was 1000 or 1024 bytes. Early diskettes always used 1000, only when the 8 bit home computer era started was the 1024 convention firmly established. Before that it made no sense to talk about kilo as 1024. Earlier computers measured space in records and words, and I guess you can see h…

> 1024 bearing near ubiquitous was only the case in the 90s or so

More like late 60s. In fact, in the 70s and 80s, I remember the storage vendors being excoriated for "lying" by following the SI standard.

There were two proposals to fix things in the late 60s, by Donald Morrison and Donald Knuth. Neither were accepted.

Another article suggesting we just roll over and accept the decimal versions is here:

https://cacm.acm.org/opinion/si-and-binary-prefixes-clearing...

This article helpfully explains that decimal KB has been "standard" since the very late 90s.

But when such an august personality as Donald Knuth declares the proposal DOA, I have no heartburn using binary KB.

https://www-cs-faculty.stanford.edu/~knuth/news99.html

Re: 1 kilobyte is precisely 1000 bytes?

#79

Post by pjdesno »

I had a computer architecture prof (a reasonably accomplished one, too) who thought that all CS units should be binary, e.g. Gigabit Ethernet should be 931Mbit/s, not 1000MBit/s.

I disagreed strongly - I think X-per-second should be decimal, to correspond to Hertz. But for quantity, binary seems better. (modern CS papers tend to use MiB, GiB etc. as abbreviations for the binary units)

Fun fact - for a long time consumer SSDs had roughly 7.37% over-provisioning, because that's what you get when you put X GB (binary) of raw flash into a box, and advertise it as X GB (decimal) of usable storage. (probably a bit less, as a few blocks of the X binary GB of flash would probably be DOA) With TLC, QLC, and SLC-mode caching in modern drives the numbers aren't as simple anymore, though.

Re: 1 kilobyte is precisely 1000 bytes?

#80

Post by adiabatichottub »

EuanReid wrote: post #64
none_to_remain wrote: post #41

Earlier quoted context omitted.

Of course! I was being silly and just thinking of "k" for the smaller one and "K" for the bigger one.

Upper-K is for Kelvin, so can't be mixed in as a prefix in case someone decides to commit physics crimes and talk about temperature-mass (Kkg).

Just throw some Joules on top there and it'll be alright
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