[X4U] External HD: 750 gig to 699 when formatted. Why???

[Randy B. Singer]

On May 24, 2009, at 10:27 AM, Germain M. wrote:

> I bought a SimpleTech 750gig external HD. It was Windows formatted  
> in the first place. Once mounted, info window showed the drive had  
> 699 gig free. As suggested in the instruction manual (and as should  
> be done) anyway), I reformated the drive Mac OS Extended journaled.  
> Still 699 gig free. Is there a way te recover this huge amount of  
> lost gig? What are they used for and by what (whom)? Are there some  
> hidden Windows programs and files left on the HD. If so, how to et  
> rid of them to recover that space?


Most of that "lost space" was lost in the advertising department of  
your hard drive's manufacturer.

Manufacturers sell the drive based on a base 10 calculation of size:  
1GB=1000MB, 1MB=1000kb 1KB=1000bytes, etc.

But hard drives are actually measured (formatted) in the real world  
using a base 2 calculation like this: 1GB=1024MB, 1MB=1024kb,  
1KB=1024bytes, etc.

So you're not really losing anything, it's just deceptive marketing.  
1GB actually equals 1073.741824MB, (1024(b)x1024(k)x1024(m)). So for  
every GB you lose approximately 74MB.  So, for instance, a 120GB  
drive, with a 74MB/GB "loss" should have 8880MB less when formatted,  
or be about 111GB formatted.

A 750GB drive should have a 55,500MB loss when formatted, for a total  
formatted size of about 694.6GB.  You got off easy.

http://answers.yahoo.com/question/index?qid=20071212184510AAP3XoY

This comes up all the time, and I've been surprised that after all  
these years that there hasn't been a false advertising lawsuit over  
this.  (There *was* a lawsuit over a similar situation in advertising  
the size of computer monitors.)

___________________________________________
Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)

Macintosh OS X Routine Maintenance
http://www.macattorney.com/ts.html
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