Hard Drive Size Misreporting Universal Question/Headscratcher

[NiteFenix]

Hi everyone.

Just a generalized question which has intrigued me for some time now.

Ever since the dawn of the age of Hard Drives the question of why size is misreported on formatted hard drives has puzzled me ceaselessly.

A quick example is your standard 40 GB Hard Drive (brand is not important). Once you have set it up and formatted it, instead of reporting it as a solid 40 GB Hard Drive, it instead shows as 38 odd GB.

This has become predominantly more apparent, especially lately with the larger LBA IDE and SATA I/II hard drives. In this case a 150 GB Hard Drive would be reported as a 130 GB Hard Drive for example (I'm speaking under correction, this figure is for demonstrative purposes only). That means, that in estimate of about 20 GB of Hard Drive space is in effect "lost".

I've researched it from a personal Point of View and I've come to the conclusion that perhaps the Hard Drive Manufacturing Companies just use the "150 GB" value printed on the label as a "guide" to give you an "idea" of how big the hard drive is, in effect rounding it off. But then I thought to myself "Hang on Jonathan, if that is the case, it would be highly unproffesional on a large company such as Seagate's behalf, and in so doing would be constituted as misadvertising, which in turn would lead to law suits and moral dillemas....the list goes on and on."

I'd like to hear your opinion on this topic. Please feel free to expand on my ideas and come up with your own explanations as to why this is how they calculate the actual size of Hard Drives.

Until next time!

Adios

NiteFenix

[FLG]

HDD manufacturers measure a 1 MB as 1,000,000 bytes and a 1 GB as 1,000,000,000 bytes (makes things easier). Though the standard for 1 MB is 1,048,576 bytes, and the standard 1 GB as 1,073,741,824 bytes.

So, Lets use a 40 GB HDD as an example

40 GB * 1,000,000,000 = 40,000,000,000 bytes

40 GB * 1,073,741,824 = 42,949,672,960 bytes

42,949,672,960 bytes - 40,000,000,000 bytes = 2,949,672,960 bytes

2,949,672,960 bytes/1,073,741,824 bytes = 2.74709702 GB

40 GB - 2.74709702 GB = 37.252903 GB

Real size of the HDD is 37.252903 GB or just 37.25 GB

Hope that clears things up.

[glc]

Apparently you didn't read the sticky threads in this forum - being that this was a question asked constantly, we stickied it. Not trying to give you a hard time or embarass you, but this is standard procedure in Internet forums - sticky threads and the search function.

Sticky: Hard drive showing wrong capacity? Here's why.

[NiteFenix]

My apologies folks. I only realised my mistake after I had posted this article. I looked for it afterward to delete it but could not find it. If you guys want to delete it, by all means go ahead

[glc]

No problem, no need to delete it. Just letting you know for future reference.