HDD does not work up to capacity

[James Tanis]

On Fri, 13 Jun 2003 13:45:30 +0200
Erik Trulsson <ertr1013 at student.uu.se> wrote:

> On Fri, Jun 13, 2003 at 01:32:32PM +0200, freebsd_deamon at gmx.net wrote:
> > this might be an incredible stupid question but since i am not that familiar
> > with disk geometry i ask it anyway:
> > 
> > I just bought an Hitachi DeskStar 180GXP HDD (it's the same as IBM) which is
> > supposed to have a capacity of 61.4 GB but i can only get approx 58 to 59
> > out of it.
> > 
> > why?
> 
> Remember that harddisk manufacturers use 1GB=10^9 = 1000000000 bytes
> (which is arguably the correct definition) while most OS's use 
> 1GB = 2^30 = 1073741824 bytes. 
> This probably accounts for the difference.
> 
> So there is not really any problem, it is just that the gigabytes that
> the manufacturer claims the disk has are not the same size as the
> gigabytes that the OS claims to see.
> 
> > 
> > is there a way arounf it?
> > 
> > some additional data are:
> > 
> > model: IC35L060AVV207-0
> > LBA: 120.103.200 sectors
> 
> According to this the disk has 120103200 sectors, each of which is 512
> bytes.
> This gives a total size of 61492838400 bytes.
> 
> Divide this by 10^9 and you get 61.49 GB
> Divide it by 2^30 and you get 57.27 GB
> 
> Those are probably the numbers you are getting, and if so everything
> should be OK.
> 
> > CHS: 16383/16/63
> > 
> > i am using an ASUS CUL2 m/b
> > 

	Although this is more then good enough a reason, don't also forget about that default 8% that UFS likes to put aside to keep everything nice and tidy :). This may not be relevent, I'm sure there's plenty of places where the OS reports the true size of the partition but I'm not sure that he states where he's pulling his info from. I had always wondered whether they pulled that power of 10 bull, never took the thought process through to doing the math. I just kind of always figured it was too much "work" for them to make sure each hd was perfect so they just kind of looked the other way on the assembly line :P.