Wow! here's one to chew over

. Thanks for volunteering me guys -

Alan, as you were first to volunteer me, don't worry, I'll get you back for this

.

Ok Den, firstly you will never get the capacity that is stated on a hard drive once it is formatted and even in the raw (unformatted) state it will not match the size stated on the drive itself.

In addition to that, even if you know the actual true raw size of the drive (not the one stated on the label), it will not match the formatted size, although this difference is quite small and is taken up by the file system of the operating system and of course the operating system itself. So Junebug is right, but there's more. The big difference comes about because of the differences of two mathematical systems.

I think we are all familiar with Metric. This is the system in every day use around the world and is a system based on the mathematical power of 10. This gives us numbers in this sequence:

1-10-100-1000-10000-100000-1000000.

Fine. All nice and easy.

Computers on the other hand, count using binary. This is a mathematical system based on the power of 2. This system gives us a numerical sequence of:

1-2-4-8-16-32-64-128-256-512-1024-2048-4096 etc.

So, our every day metric system goes like this:

kilo = 1,000

mega = 1,000,000

giga = 1,000,000,000

With binary used for computer data storage it goes like this:

Kilobyte = 1024

Megabyte = 1,048,576

Gigabyte = 1,073,741,824

Terabyte = 1,099,511,627,776 (1024x1024x1024x1024)

That's what makes up the big difference. When the computer calculates the hard drive capacity (using binary) it takes 1,073,741,824 bytes (actual gigabyte) for every 1,000,000,000 bytes (Decimal or manufacturer's gigabyte) which is why the overall capacity will seem less than that stated by the manufacturer.

To confuse matters even further, computers also use decimal counting (CPU clock speed for example)

Then there is the manufacturing, sales and marketing side of things. It is far easier to term Hard Drive sizes in decimal rather than binary so it was decided that a gigabyte would be 1000,000,000 bytes etc. It also made the disks look bigger (theyre not in actual fact. They are the same size but just specified differently).

All in all, 1397.26 sounds about right for your drive. The bigger the drive capacity, the bigger the difference. Without doing the maths I think it's somewhere around 7 or 8% of what is stated on the label (decimal). That's why, when you install and format your drive, it shows up as less than you thought you bought.

Phew, I think that's about it. If I try to go any further with this I'll need therapy. Someone else can do the maths if they want to - over to you Junebug

(well you didn't think you'd get away with volunteering me did you?)

Hope that helps.