How do you measure hard disk capacity?
Posted on 25/10/07 17:16 by geno 888                             
How do you measure hard disk capacity?

It is not uncommon that customers are fooled by the way hard disk capacity is measured, that is different from the way computers measure the same thing. In fact, many people wonder why after installing the disk the total capacity shown by the operating system is lower than expected.

HDD manufacturers define one gigabyte as one billion bytes, whereas the operating system (i.e. the computer) shows the real value. A gigabyte is technically defined as 1.074 billion bytes. The greater the capacity, the higher is the difference between advertised value and actual capacity. For 1 TB disks, the difference is around 10%.

Not all people, however, are happy of this. On a news published at Ars Technica is reported that in 2005 a woman named Sara Cho sued Seagate alleging that the company's use of binary when reporting hard drive sizes constituted false advertising.  As reported at Ars Technica:

Seagate has agreed to issue a refund equal to five percent of a drive's original purchase price, provided the hard drive was bought between March 22, 2001 and September 26, 2007. Alternatively, customers can request a free set of Seagate's backup and recovery products (valued at $40).

More detailed information can be read here.

 

Reactions
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By none (guest), Thu 25 Oct 2007 20:57
Does the Seagate settlement mean they're going to stop their deceptive practice of over-reporting HDD capacity?
By Web-Junkie, Thu 25 Oct 2007 21:59
About bloody time this false advertising was brought out into the open! I hope ALL Hard Disk manufacturers will now be forced to compensate customers for this dishonest advertising! Monitor manufacturers now have to state the VISIBLE size of the screen, so it's about time Hard Disks had the REAL FORMATTED capacity given! So does that mean I now have to sue Seagate in the UK to get my compensation for my 2 Seagate hard drives I purchased in 2003? I doubt this will benefit anyone though, we won't see new HD's suddenly format to the 'real' capacity they quote for the same money!!
This message was edited at: 25-10-2007 22:00
By FidelC, Fri 26 Oct 2007 05:15
FidelCI always wanted to sue M$ for underestimating my HDDs supergrin ..and then Geno for spreading false rumors about 1GB =1.074 billion bytes. devil
By Bekali (guest), Fri 26 Oct 2007 07:54
Or operating systems should count 1KB=1000B, or HDD and Optical Media should have 1KB=1024B . Otherwise the consumers will not be happy. cool The CDs have proper labeling Smilie , but DVD and HDD not. Frown Me, wont 1KB=1024B cool
By pinkish, Fri 26 Oct 2007 11:07
FidelC, that remark is funny biggrin anyway, i don't really see what the problem is, so it's less... so what? it's been like this forever, it's not like you don't know!!!
By Powderhorn, Fri 26 Oct 2007 14:30
Yes, it's been this way forever, but with each order of magnitude, the problem becomes worse. On a 20MB HD in the mid-'80s, the discrepancy was 4.6%. On a 1GB HD in 1995, the difference was 7.9%. But now, on a 1TB HD, the gap has swelled to 9.1%. This is nearly double the "error" reported 20 years ago, and common parlance has not differentiated terabytes from tebibytes, nor can we expect it to anytime soon. That said, in other areas, such as flash media, the rated GiB are correct, as they are in system memory. Regarding monitor size, that was not an edict from up on high when the transition was made to LCDs -- companies themselves agreed to use the viewable diagonal as opposed to the CRT case-diagonal standard. FWIW, I think diagonal measurements are a crock to begin with, but we're one step closer to honesty there. As for the fact the CDs were rated in MiB, while DVDs (and, apparently, HD formats) have reverted to GB, it's all about marketing. If you think the data loss is bad at 4.7GB to 4.37GiB, just think about the fact that the standard is called DVD5. I'd expect that at some point, this will all be sorted out, but with hard drive companies fighting it tooth and nail. If people went to the gas station and got 9.1% less gas than they were expecting, Congress would be holding hearings. Of course, the hearings would just be for show because Big Oil owns the government, but that's a different rant. I doubt the Seagate lobby is all that strong.
This message was edited at: 26-10-2007 15:00
By FidelC, Fri 26 Oct 2007 21:06
FidelC@pinkish: Thanks. I know everybody knows that I should have known, but there I was opening a fresh 2-5 pack of freshly bargained mini DVDs childishly hoping to fit 2 x700mb rips on them and seeing those nasty Imgburn messages related to shrinkage. And there was no cold water to blame.. cry p.s when bytes bite dont turn the other cheek. old wisdom
This message was edited at: 26-10-2007 21:10
By punistation, Sat 27 Oct 2007 03:02
punistationSigned. We've been screwed by this "conventional wisdom" for too long. NEXT: ISPs advertising their plans using the THEORETICAL MAXIMUM speeds.
By tiker (guest), Fri 2 Nov 2007 20:04
I'm glad this has finally happened! Now someone please go after sandisk for their false flash card sizes!
By pnoytechie (guest), Fri 29 Feb 2008 15:54
"HDD manufacturers define one gigabyte as one billion bytes, whereas the operating system (i.e. the computer) shows the real value. A gigabyte is technically defined as 1.074 billion bytes." What? BILLIONS? FidelC already pointed this out (though via joke) and the author didn't even bother to rectify it?

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