Mysterious drive capacity numbers....?

[Karl Auer]

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)...?

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/kauer/                   +61-428-957160 (mob)

GPG fingerprint: DA41 51B1 1481 16E1 F7E2 B2E9 3007 14ED 5736 F687
Old fingerprint: B386 7819 B227 2961 8301 C5A9 2EBC 754B CD97 0156
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