If you've ever gone to buy a hard drive
or SSD, and you went to plug it in, you may have noticed that something
doesn't add up. If it's a 1TB drive, it'll only show as 931GB. If it's a 2TB drive,
it'll only show as 1.81, and so on. So what gives? Surely this is false advertising by
the manufacturers! But actually it's not. They are telling the truth. The discrepancy
comes from the units being used. There are some other possible reasons I'll mention at the
end of the video, but those aren't the main focus of this video. So first I'll explain why this
discrepancy happens, and then we can get into the philosophical discussion about who's right and
who's wrong, because it depends on who you ask. So let's take a 1TB drive for example.
1TB is equal to 1000GB. Now stop, because I already see some of you rushing to the
comments to say, "It's not a thousand!" Hold on, I'm going to address that, that's literally the
whole point of this video. Now everyone has heard of kilobytes, megabytes, gigabytes, terabytes,
with the abbreviations, KB, MB, and so on. But have you ever heard of kibibytes,
mebibytes, gibibytes, and tebibytes? Yes, they're actually a thing, and they
use the abbreviations KiB, MiB, GiB, and so on. The difference between them in
terms of number of bytes is that megabytes and the others are powers of 10, whereas
mebibytes and the others are powers of 2. So there's 1024 kibibytes in a
mebibyte, 1024 mebibytes in a gibibyte, and so on. And while they're
pretty close in actual numbers of bytes, the higher you go, the more they diverge.
So if you want the spoiler answer to the question from the beginning of the video, the
reason, for example, that a 1TB drive shows up as 931GB in Windows is that behind the
scenes, Windows is measuring the number of gigabytes or whatever in terms of gibibytes, but
it incorrectly displays the labels as gigabytes. And the same goes for terabytes. It's measuring
and displaying the number of tebibytes, but the units show terabytes. And since a gibibyte
is larger than a gigabyte, 1.074 times actually, if you divide 1000 gigabytes by 1.074, you
get that number 931. That's where that comes from. So if you buy a 1TB drive, you are
indeed getting 1 trillion bytes of storage. Now side note, many people would say that Windows
isn't actually wrong in displaying these units, I'll address that later. Now
you might be thinking, wait, why doesn't Windows use the right units?
And why haven't I even heard of these gibibytes and everything else before?
Well, since the early days of computers, because computers use binary, it's easier to
actually deal with numbers in powers of two. And you probably recognize these numbers, they
come up a lot when dealing with computers. And when they got to 1024 bytes, long story short,
people decided, eh, that's close enough to 1000, we'll just call it a kilobyte. And since
every 10 powers of two is close to its corresponding decimal number anyway, the
other prefixes could just be used too. Except this predictably became confusing
with people using the terms of megabytes and gigabytes and everything else for
both the binary meaning and the decimal meaning. Meaning binary with the powers of two
meaning and decimal as the power of 10 meaning, but still calling them the same thing,
gigabytes and megabytes and whatever. So the IEC, a standards organization came
up with those new prefixes to be used for the binary based units instead, so you
could discriminate between them. And they came up with the names by just taking the
"bi" part of binary and sticking that on, and using that. The problem is those units
never really caught on in the mainstream. They are actually officially
recognized though. For example, the National Institute for Standards and
Technology requires the binary prefixes to be used if you're referring to such units.
But as the difference between the binary and decimal units became larger and more obvious
with bigger drives, many companies and people just started using the decimal meaning
only, which is way more intuitive anyway. And that way they can just keep using the same
unit labels. For example, in 2009, starting with Mac OS 10.6, Macs use the decimal units with their
proper prefix. And since at least 2010, the Linux distribution Ubuntu has also had a policy to use
the official units. If you're using a Mac or most distributions of Linux, then you'll probably
see the same number that shows on the box. I believe hard drive manufacturers have
always used the decimal meaning. And also if you're talking about network
speed, like one gigabit per second, that has always referred to the decimal
meaning also. So a big reason why you rarely see these units and prefixes is because
most people aren't using them anyway, they're just using the decimal meaning of
gigabytes. There are some holdouts though, who are using the binary units,
but displaying the decimal label, namely Microsoft Windows and RAM manufacturers
as big ones. At least in Windows, if you do go to the properties window of a directory or file,
it will show you the exact number of bytes, but for most people I think that is
just going to add to the confusion. So why does Windows do this?
Well, if you go back to 2009, the reasoning was that nobody else
was. So okay, fair enough. At the time, you could make the consistency argument.
I mean that blog post was from before Mac OS had even switched over later that year. But
why Windows still does this really confuses me. And I'm not even saying that I expect
them to start using the binary labels, that would just confuse virtually everyone.
Rather behind the scenes, they could start just showing and measuring in the decimal
units and keep the same label. And honestly, no one would even notice or care. There's not
anyone out there who would say, "Wait a minute, yesterday this Microsoft Word document
was 1.28 megabytes and now it's 1.34. What gives?" Surely a lot of people would notice
that their hard drive capacity has changed, but it would look like their hard drive got
bigger. So I doubt they're going to be mad about it. So if Microsoft is maybe worried that
a change after this long would be confusing to people, well, I would argue there's
nothing confusing about plugging in a drive and seeing the same number that's
listed on the box that you're expecting. I mean, I remember even ages ago buying a
64 megabyte memory card for the Xbox 360 and being pissed when I plugged it in and
saw there was only 61, seemingly. Because back then every megabyte mattered. And even
if there is some compatibility issue behind the scenes with how settings or Windows
operates, what you could do is just change how it's displayed in Windows Explorer only,
which is what would matter for 99% of people. And then just keep using the binary units for
any calculations behind the scenes. And you could even switch those over to use the binary
labels. Now I mentioned RAM manufacturers before, and they also use capacities in powers
of two and display the decimal unit labels. Apparently they do have a legitimate
reason for using the binary units at least, because of the way logical and
physical addressing works in memory. But I still think they should use the right
labels and call them the right thing. Finally, at the beginning, I did mention that there
are some other possible causes for why a drive might show a lower storage capacity,
one of them being a hidden partition. A lot of prebuilt computers will come with a recovery
partition that's hidden, and that will make the main partition show smaller, but that's because
it's actually being used for something else. I've seen some people mention that the
operating system will take up space, but that wouldn't actually reduce the
capacity of the drive that'll just show as space taken up. Others have pointed out that
the file system itself, like NTFS, may take up space on the drive, and while technically
true, that would be relatively negligible, especially the difference compared to
the units that's showing differently. And also, I'm not even sure if that
would reduce the total capacity shown, or if that would also just show as space taken up.
In any case, hopefully this cleared something up, and if you were mad about drives not
being as big as they should be, well, rest assured, you are getting what you
pay for. At least most of the time, there are cases of scam flash drives being
sold on Amazon that say it's like 10 terabytes, but really, they just mess with the firmware,
but that's maybe a whole nother video. So hopefully you learned something. Be sure to
give this video a thumbs up if you enjoyed it, let me know down in the comments what you
think. Did you know about this before? Maybe you're a computer genius,
and you did. Also maybe consider checking out some other recent videos
on my channel, and maybe subscribe. If you do, be sure to click the bell to enable all
notifications. These days, even if you subscribe, YouTube still might not show you the
videos. If you want to keep watching, the next video I'd recommend is where I talked
about secrets of the Windows calculator. There's a lot about it that you might not know
about, so I'll put that link right there. So thanks so much for watching guys,
and I'll see you in the next one.
