There are already several friends who, not being understood in computer science, ask me the same question. They don't understand why their HDD has less gigs than advertised.
When we buy a hard drive, pendrive, Mac or iPod (which of course has its hard disk inside) its capacity is indicated on the product packaging. For example 32GB, 128GB, 320GB, 500GB, 1TB disks, that is, "Gigabytes".
En English byte, not to be confused with a “bit”, is translated by octet. 320Gbytes is 320GigaBytes, abbreviated 320GB.
Well, we bought a MacBook Air with 128GB solid disk SSD, we went through the box, we got home and plugged it in. When we look at the capacity it has, we are surprised:
The same happens with an external hard drive, pendrive or iPod ... The 128GB have become just over 121GB. If you want to check how many appear on your computer you just have to enter the folder "OTHERS" of the Launchpad and launch the tool "Disk Utility", where in the left sidebar you can select the discs you want and in the lower right corner of the screen the information appears.
Loss varies according to the advertised size hard drive, but there is always a difference. Have you been cheated on? Yes and no.
This difference is due to various factors. The main reason is that computer scientists and marketing aces they do not conceive of mathematics in the same way.
As seen in the screenshot above, the total disk capacity actually indicates 121 billion-odd bytes: 121.332.826.112, to be exact. Consequently, one has to think that the album does indeed have those “gigs”. And that's what the marketing gurus insist on saying to sell us a "128GB" disk. It sounds great but it is not totally true.
The problem, as we have already seen, is that 1 kilobyte does not equal 1000 bytes, but 1024 bytes. Consequently, 1 gigabyte is not equal to 1.000.000.000 bytes, but to 1.073.741.824. Consequently, to have “real” 128GB, the disk would have to be 134.217.728.000 bytes, instead of 121.332.826.112. Marketing is incapable of multiplying by 1024.
To avoid possible accusations of deception or worse, manufacturers and sellers always indicate that the "Actual size may be smaller".
Here, the bottom of the MacBook Air spec page on Apple's site.
Contrary to what we are told in this message, it's not formatting what makes the difference, but how to “simplify” the calculation. The argument often used is that "it's easier for the customer." Personally, I would say that 128GB, written nicely and conspicuously on the product label, sells better than an exact number like 121.33GB.
As of today, “giga marketing” is lighter than “gigabyte”.
Learn more - Apple offers Fusion Drive on the entry-level 21,5-inch iMac
Totally uncertain, it is the manufacturers, not marketing, who make the hard drives of that size and not the real one. As you say, the manufacturers dictate that 1MB is 1000KB instead of 1024KB that the theory says.
I want to say that the marketing of the manufacturers (who are the ones who put the labels and make the boxes) round it up so that the consumer does not get confused. Thanks for the input.
Something similar happened to me, a friend was furious because if the laptop said that her disk had 450 GB instead of 500 and more when she saw that my MacBook Pro marked 499.7 GB of capacity, she thought that it had been stolen until I explained how it worked the matter and calmed down more when he saw that when I went to BootCamp instead of dialing 499.7 it marked only 457 GB
The explanation of the article is wrong. A kilobyte if they are 1000 bytes (10³) the problem is that base 10 is used, and what if they are 1024 bytes is 1 kibibyte, or what is the same 2 raised to 20.
I wanted to put 2 to the power of 10
You are right that in digital electronics, the decimal system that has base 10 is not used, that is, the set of numbers that are used to generate all the others are 10, so when we want to know how many different possibilities we can generate with Three digits in decimal would raise the base of the system to 3, which is 10. In the case of digital electronics, which is the one on which writing on hard drives and data memories is based, the system used is base two. In other words, this time it is two digits, the "0" and the "1" that are used to generate all the other numbers. We then call this system BINARY. To know the possibilities that exist when we have 3 digits, we raise BASE 3 to 2, that is, two raised to three, which is 8 possibilities. In our case two raised to 10 is what actually gives 1024, since the capacity is calculated by powers of 2. If you realize it, this is what I have done to be able to reach the capacity of 134.217.728.000. Thanks for your input!
Buff, you made me have to think… 😉.
The calculation is correct, what I am going to is that depending on the measurement in base 2 (binary) or in base 10 (international system) the denomination of the multiples of the byte varies. It would be kibibyte for base 2 and kilobyte for base 10. I'm not saying that your calculation was wrong, but, being pejiguero, the multiples of the base 2 byte must be called differently according to what the IEC8000-13 standard says:
«The unit was defined by the International Electrotechnical Commission (IEC) in December 1998 and established the storage standard of 1024 bytes with the nomenclature of KiB instead of kB as it was previously and call it kibibyte, to differentiate it from kilobyte, since it is then gave many errors among them. " (Wikipedia source)
So if the manufacturer of the hard disk gives you the data in kilobytes, the operating system in kibibytes, but then they also mistakenly call it kilobyte, the thing ends in confusion for the vast majority of consumers.
Thanks for answering, I find it a very interesting topic.
Thanks for the new clarifications about the Kibibyte. Users who read us will now have a much clearer concept.
Not only do they have this problem, the worst is that the system, programs etc ... that in a normal disk need 35 gigabytes in the ssd they need almost 60, check it and you will see, they have sold us the well-sold motorcycle, be careful with what you buy.
Please could you answer me this …… I have an ibook g4 with a 40 GB disk but after doing several formatting for about 5 months, I see that the number of GB's has decreased until it reaches the one that right now, I have 37,14 GB's. this is why they explained earlier?
Because although 40gb's appeared before, it has now dropped in capacity despite the fact that at one time it said that its capacity was 40bg?
in short, more explicit. when I got my machine and formatted it for the first time, it said that its total capacity was 40GB. now after several formats the total capacity says that it is 37.14gb's.
is something happening with my hard drive =?