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# Hard Drive Capacity

6 replies to this topic

### #1 Lilium

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Posted 01 October 2010 - 08:38 AM

I have an External TB HDD, but my computer says its max capacity is 931gb. Why is that? My other external hdd has the same issue; 120gb hdd, but I can only use 111gb of it? The interesting thing is when I view both hdd's while running Parted Magic, it shows my full capacities and not the lowered ones. Can anyone explain why this is happening?

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### #2 buddy215

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Posted 01 October 2010 - 09:21 AM

Manufacturers make drives in what is known as a decimal size, where Kilo = 1000

So for the example take a 10Gb drive which has 10,000,000,000 bytes.

But a binary Kilobyte has 1024,Bytes, so you have to divide 10,000,000,000 by 1024 ...

10,000,000,000 Bytes ÷ 1024 = 9765625,Kb

9765625,Kb ÷ 1024 = 9536,7431640625,Mb (9536,74Mb)

9536,7431640625Mb ÷ 1024 = 9,31Gb

(If the manufacturers had made a 10Gb drive with 10737418240,Bytes you would have a full 10Gb)
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### #3 hamluis

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Posted 01 October 2010 - 12:24 PM

What Buddy said...in more words , Hard Drive Sizes.

Louis

### #4 Lilium

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Posted 01 October 2010 - 02:44 PM

Okay, I understand. Thank you too Hamluis for the link. I appreciate the both of you responding so quickly. *sigh* It's still kind of lame that I can't use the 70gb of storage I paid \$150 for. Are there hdd's that function on something other than binary, can be used on Windows, and won't limit capacity?

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### #5 hamluis

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Posted 01 October 2010 - 04:39 PM

There is no limit of any sort.

Manufacturers intentionally use a smaller number to determine what makes up a MB, GB, etc. Althoough it can be logically justified, it is not in tune with the standard that is numerically correct for computer application.

You get exactly what you paid for, but it really isn't quite as large as stated by hard drive manufacturers.

It has always been this way, as long as I can remember...which is back to the 3.2GB hard drive days.

Louis

### #6 dc3

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Posted 01 October 2010 - 04:42 PM

Okay, I understand. Thank you too Hamluis for the link. I appreciate the both of you responding so quickly. *sigh* It's still kind of lame that I can't use the 70gb of storage I paid \$150 for. Are there hdd's that function on something other than binary, can be used on Windows, and won't limit capacity?

The link that was posted spells it out in very plain verbiage. Binary is the recognized means of graduation with RAM and hard drives.

Edited by dc3, 01 October 2010 - 05:56 PM.

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### #7 Platypus

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Posted 01 October 2010 - 06:27 PM

SSD manufacturers appear to be using GiB values. My 30GB Vertex has 32,014,069,760 bytes capacity. A hard drive of this capacity would be called 32GB.

But as the others have said, it's vital to recognise that there hasn't been any limiting or loss of capacity when a 1TB drive is reported as having 931GB - it's just two different ways of naming the same capacity.
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