[kmm]

And a megabyte is depending on the context precisely 1000x1000=1,000,000 or 1024x1024=1,048,576 bytes*, except when you're talking about the classic 3.5 inch floppy disks, where "1.44 MB" stands for 1440x1024 bytes, or about 1.47 true MB or 1.41 MiB.

* Yeah, I read the article. Regardless of the IEC's noble attempt, in all my years of working with people and computers I've never heard anyone actually pronounce MiB (or write it out in full) as "mebibyte".

[superjan]

Well the 1.44 MB, was called that because it was 1440 KB, twice the capacity of the 720k floppy, and 4x the 360k floppy. It made perfect sense to me at that time.

[okanat]

It may "make sense" but that's actually a false equivalence. The raw disk space for a 3.5" high-density floppy disk for IBM PCs is 512 bytes per sector * 18 sectors per track * 80 tracks per side * 2 sides = 1,474,560 bytes. It is 1.47 MB or 1.40 MiB neither of which is 1440 KB or KiB. The 1440 number comes from Microsoft's FAT12 filesystem. That was the space that's left for files outside the allocation table.

Sectors per track or tracks per side is subject to change. Moreover a different filesystem may have non-linear growth of the MFT/superblock that'll have a different overhead.

https://en.wikipedia.org/wiki/List_of_floppy_disk_formats

[pif]

> I've never heard

It doesn't matter. "kilo" means 1000. People are free to use it wrong if they wish.

[tombert]

All words are made up. They weren’t handed down from a deity, they were made up by humans to communicate ideas to other humans.

“Kilo” can mean what we want in different contexts and it’s really no more or less correct as long as both parties understand and are consistent in their usage to each other.

[bloppe]

If Bob says "kilobyte" to Alice, and Bob means 5432 bytes, and Alice perceives him to mean 5432 bytes, then in that context, "kilobyte" means 5432 bytes.

[lightedman]

Man let a drug dealer give me a binary 'kilo' of some drug. That's almost a free ounce included!

[burnt-resistor]

Such a myopic view when reality and marketing is messier than dramatic self-righteousness. This unnecessary bikeshedding nonsense has already been solved by using mebi, kibi, etc. to disambiguate sloppy abuse of SI units.

[nixpulvis]

Exactly.

If you're talking loosely, then you can get away with it.

[whichquestion]

I worked with networked attached storage systems at pib scale several years ago and we referred to things in gib/tib because it was significant when referring to the size of systems and we needed to be precise.

That being said, I think the difference between mib and mb is niche for most people

[fc417fc802]

Speaking of significant Pib vs PiB is 8x. I assume you meant the latter.

[burnt-resistor]

Interestingly, HD floppies actually are 2 "MB" unformatted without the various overhead. This is how 1.68 "MB" DMF is possible. Extra-high Density (ED) 2.88 "MB" is similarly 4 "MB" unformatted.

[pwdisswordfishy]

> classic 3.5 inch floppy disks

90 mm floppy disks. https://jdebp.uk/FGA/floppy-discs-are-90mm-not-3-and-a-half-...

Which I have taken to calling 1440 KiB – accurate and pretty recognizable at the same time.

[skissane]

> 90 mm floppy disks. https://jdebp.uk/FGA/floppy-discs-are-90mm-not-3-and-a-half-...

That page is part right and part wrong.

It is right in claiming that "3.5-inch" floppies are actually 90 mm.

It is wrong in claiming that the earlier "5.25-inch" floppies weren't metric

"5.25-inch" floppies are actually 130 mm as standardised in ECMA-78 [0]

"8-inch" floppies are actually 200 mm as standardised in ECMA-69 [1]

Actually there's a few different ECMA standards for 130 and 200 mm floppies – the physical dimensions are the same, but using different recording mechanisms (FM vs MFM–those of a certain age may remember MFM as "double density", and those even older may remember FM as "single density"), and single-sided versus double-sided.

[0] ECMA-78: Data interchange on 130 mm flexible disk cartridges using MFM recording at 7 958 ftprad on 80 tracks on each side), June 1986: https://ecma-international.org/publications-and-standards/st...

[1] ECMA-69: Data interchange on 200 mm flexible disk cartridges using MFM recording at 13 262 ftprad on both sides, January 1981: https://ecma-international.org/publications-and-standards/st...

[nixpulvis]

They should be more precise if they are talking about KiB in a context where the difference matters... luckily those contexts are usually written down.