When is 500GB not 500GB

[expat]

Today I bought an external hard drive, mainly to use a picture backup, however once it was plugged in I noticed the following:

On the box an nice big red label, 500GB  
Plugged in and get 499,983,024,128 Bytes followed by a capacity of, 465GB.

So is the drive 500GB or not. Is counting the bytes and then converting them to GB, which is not the capacity GB a little fraudulent. I wanted a 500GB Capacity and not a 465GB.

Matt

[machineman9]

I think sometimes they give it in GiB, which messes up the values a bit.

But yeh, 465GB does sound like a 500GB HDD

Cant remember how they do scam you out of that little bit (the actual figures) but they do  ::)

[MWISimmer]

It's a decimal thing, counted in multiples of 1000 not 1024.

Yes it's marketing and nothing more, but ALL regular HDDs are measured the same way. So whilst it's true you're not getting your "advertised" capacity, it's not far off.

8 bits to a byte
1024 bytes to a kb
1024 kb to a Mb
1024 Mb to a Gb
etc..

So..

1024x1024 bytes = 1 Mb = 1048576 bytes
1048576x1024 = 1Gb = 1073741824 bytes

x 465 = 499289948160 which when divided by 100,000,000 equals as near as 500Gb as doesn't matter.

Hope that helped.. it confused the hell out of me just working it out

[expat]

It's a decimal thing, counted in multiples of 1000 not 1024.

Yes it's marketing and nothing more, but ALL regular HDDs are measured the same way. So whilst it's true you're not getting your "advertised" capacity, it's not far off.

8 bits to a byte
1024 bytes to a kb
1024 kb to a Mb
1024 Mb to a Gb
etc..

So..

1024x1024 bytes = 1 Mb = 1048576 bytes
1048576x1024 = 1Gb = 1073741824 bytes

x 465 = 499289948160 which when divided by 100,000,000 equals as near as 500Gb as doesn't matter.

Hope that helped.. it confused the hell out of me just working it out  :P  ;D ..and may still be wrong  ;)

So it is a accepted fraud by the various hard drive companies. Wonder what would happen if I took it back on the grounds that it only has a usable capacity of 465?

Matt  

[NickN]

The size is there however access to every byte is based on several things and one item is mentioned above.. the math and how you calculate space

the reason it does not register as 500GB is because of the conversions howver there is also 2 other areas that affect this value..

1. Windows formats the drive.. the larger the cluster used in the format, the less drive space after the format

So if you were to use 64K as the cluster size instead of the standard 4K the amount of disk space lost to system would be much greater. Some 3rd party disk software will show you the breakdown based on the cluster size selected before format.


2. If this drive will have the OS on it, typically Windows reserves a space which is not seen in Windows and the amount reserved can vary based on the total size of the Windows drive/partition. This space can be anywhere from a few MB to 1-5GB

[HarvesteR]

also, a poorly partitioned HD can also show up i windows with some space missing, simply because it was never mapped during partitioning

but, mainly, companies advertize 'nominal' HD size capacities, which is a fancy word for 'rounded up'  :P

i know.... bummer... well, that's how the cookie crumbles these days  ::)

Cheers

HarvesteR

[Mazza]

It's kinda like RAM , 1Gb is not 1Gb it's 1024Mb and so on...

[machineman9]

It's kinda like RAM , 1Gb is not 1Gb it's 1024Mb and so on...

Not quite, but I know where you are coming from...

The way it is worked out is that 1024Mb make a Gb. It is just equal to that.

Its base 2, binary. Each of those 0s and 1s in binary make up different amounts, like this:

0000000000
That is '0'. Reading right to left each number goes up in the base 2 format... so from right to left it is 1,2,4,8,16,32,64,128,512,1024 etc. If they are '0' then they arent used, if they are '1' then they are. To write the number 15 it would be as simple as 00001111. 1+2+4+8=15

I dont know the exact reason for using 1024 as the base for a gigabyte, but it is there using the base 2 binary format.

[pepper_airborne]

It is the only thing a computer can do, in essence all it does is moving 1's and 0's around and basic math with them.

[homebrewer]

It sounds to me like the drive was already formatted for you. Someone correct me if I am wrong, but is it not possible to only get 137Gb out of a drive larger than that if the unformatted drive is not correctly formatted (for Windows)?