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I see this repeated time and time again, and every time it isn't true.

This is what my console shows when it sees a 1 TB drive:

[ 1.629496] sd 2:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB)

If you multiply those 2 numbers (1953525168 x 512 bytes), you arrive at 1000204886000 bytes, or 1000.204886 GB. You can write to every single one of those bytes/sectors, none of them are reserved.

Your choice of filesystem dictates the maximum amount of space you can use on the drive, but the drive itself is giving you all of the capacity you asked for, and if you don't use any filesystem at all, you can write 1TB to it.

The confusion comes from Microsoft Windows being involved. Windows measures in IEC units, but displays the value as an SI unit.

So, for example, it will tell you that a 16000000-byte file is 15.26 MB. It isn't. It's 16 MB; it is also 15.26 MiB. Likewise, Windows will tell you that a 1 TB harddrive is 931 GB. It isn't, it's 1000 GB; it is also 931 GiB.

If I'm a cable vendor, and you ask me for a reel of 8 kilometres of cable, and I give you a 5-mile reel, I gave you what you asked for. 5 is less than 8, but 5 miles is not less than 8 kilometres. 931 is less than 1000, but 931 GiB is not less than 1000 GB.



> I see this repeated time and time again, and every time it isn't true.

What isn't true? That they're using a definition that's technically correct but doesn't align with the lay definitions of the units?

I don't think you can call that untrue, no matter how prescriptivist you get.

And it's worse than that, because other technical users also mean powers of 2^10.

And it goes far beyond Windows, and has nothing to do with file systems.


Gibibyte is not a different definition of gigabyte. They’re different units.


I though it was SI retroactively standardizing the Ki Mi Gi prefixes in an attempt to fix things, and before that the common usage of GB was just 2^30 Bytes.

The SI system can give a definition of GB, but that doesn't mean they have given the definition of GB.


Neither. G is the SI suffix Giga, and always means 1,000,000,000. GiB is an IEC unit, not an SI unit. They're from entirely different bodies.


When they shorten it to “G” they are absolutely trying to deceive.


On reading this on iOS I selected the word and pressed “look up”. It seems that iOS strips out formatting in its dictionary, make superscript full size. Not ideal. Gigabyte “a unit of information equal to one thousand million (109) or, strictly, 230 bytes.”


That's exactly what he meant.




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