Right, so I was wondering whether someone could clear something up for me. Why is it that retailers sell Hard Drives of 80GB, 160GB, 320GB, 500GB, 750GB, 1TB etc, yet when they arrive, and you've got them properly placed etc, you go to check and find that they aren't actually what they've been labelled as. My current system is suppose to have a 160GB HDD, I've actually got 152.65 (of which is devided into four partitions, one of which is the system recovery). I've recently purchased a new system too (which came today). Ordered a 500GB Hard Drive, and once again, it isn't what I've got. I've actually got something like 465GB's. I've checked the disk managment tools too, on both fronts, yet there is nothing 'spare' to add. Whats going on?

Hard drives are labeled in 1000mb/1gb and when you format it, it goes to the 1024mb/1gb format that software uses.

I don't understand.

There are two ways you can count space on your hard drive. One is in base ten, in which case 1000^3 = 1,000,000,000 bytes is a gigabyte. The other, is in base 2, which is used because 2^10 is 1024. In which case 1024^3 is also a gigabyte (in fact, the nomenclature of this has been officially changed, so that this sort is now know as a GiB - gibibyte, which stands for a gigabinary byte).

For example, with your 160GB HDD, which should have 160,000,000,000 bytes, the actual number of GiB, which Windows uses, should be a lot less.

I think it is false advertising. They should display a '500GB HDD' as a 465GB HDD if that is all you are going to get out of it.

It's not really false advertising, since even though the GiB and GB are officially separate, both binary and decimal uses of GB are still so common its not actually false, and also because decimal is more intuitive to understand.

In most cases, Latin prefixes indicate numbers divisible by 10, i.e:

kilo- = 1,000 mega- = 1,000,000 giga- = 1,000,000,000

and so on.

When it comes to computer data, the prefixes are altered slightly, because the numbers are all powers of 2 (2, 4, 8, 16, 32, 64, 128, 256, 512, 1,024, etc.)

In this situation, the prefix "kilo-" refers to the closest number to 1,000 that is still a power of 2, in this case 1,024. This applies to the other prefixes as well.

On the label, 1 gigabyte is 1,000 megabytes. However, a computer treats 1 gigabyte as 1,024 megabytes.

So if a drive is labeled 500GB, it's based on a factor of 10, but in your computer, it's all in powers of 2. Do the math and it all works out. You still have 500,000,000,000 bytes.

I hate Computer Science. :( But you seem to be right. Just checking I wasn't being screwed over or anything.

Nope. By conventional mathematical logic, you get every byte you paid for. It's just that computers have a weirder way of defining how to divide them up into KB, MB, GB, etc. =p

To be fair, binary is a lot more logical than base 10. More numbers are factors of 2, binary is a lot simpler to show intuitively, and the only reason we use base 10 is because that's how many fingers we have.