[lug] directory/image/cd file space usage differences

[Alan Robertson]

"qqq1one @yahoo.com" wrote:
> 
> Recently I noticed that I get a slightly lower value
> returned by du when I run it on an image vs the cd the
> image is burned onto vs the directory the image was
> produced from.  What accounts for this?  Example
> below.


Different filesystem formats.

In the case of the image, it includes indirect blocks that Linux needs to
represent the image in the ext2 fs you're probably running.  So, you've
wrapped the image in the ext2 FS format.

The ext2 filesystem format has different metadata layout requirements than
the iso format the CD uses.

	-- Alan Robertson
	   alanr at unix.sh