Mysterious drive capacity numbers....?

[Ric Moore]

On Tue, 2010-12-14 at 19:44 +1100, Karl Auer wrote:
> Hi all.
> 
> I have a conundrum.
> 
> here are lines from "mount" and "df -k" showing a connected USB hard
> disk:
> 
> /dev/sdb1 on /media/nc1 type ext3 (rw,nosuid,nodev,uhelper=hal)
> 
> Filesystem           1K-blocks      Used Available Use% Mounted on
> /dev/sdb1            961432072  57820632 854773440   7% /media/nc1
> 
> Note that the amount used is given as 57,820,632K - about 57GB.
> 
> But 961 - 854 = 107. Where did the extra 50GB go?
> 
> I thought it could possibly be the blocking factor at work - but the
> lion's share if the data on that drive is large files - ISO images, VMs
> and so forth.
> 
> Also, the above numbers are a snapshot from an ongoing backup. The 50GB
> difference has remained constant for some time. Unfortunately I did not
> look at the drive capacities when it was freshly formatted - I suppose
> there could be 50GB of bad blocks...
> 
> My current guess/hope is that it is formatting overhead, though 50GB
> seems a bit excessive.
> 
> Can anyone throw light? Or point me to a good tool for looking at the
> drive (non-destructively)...?
"Disk Utility" is a peach of an app. Give that a whirl. It should be
installed. Ric


-- 
My father, Victor Moore (Vic) used to say:
"There are two Great Sins in the world...
..the Sin of Ignorance, and the Sin of Stupidity.
Only the former may be overcome." R.I.P. Dad.
Linux user# 44256