[Nottingham] Secure deletion of files

[Paul Sladen]

On Thu, 26 May 2005, Luke Crowe wrote:

Hello Luke,

> Why not just chattr -/+s  filename
> sets secure deletion on a file basis

It was actually written to keep the Ubuntu LiveCDs small, but still keep
them rsyncable so that people working on testing them don't have to
download the disk from scratch each time.

The LiveCDs consist of a huge 3GB filesystem image (ext3) that is compressed
using cloop.  This image is maintained between testing CD versions so that
it is as similar to the previous revision as possible;  and so the unused
portions need to be 'cleaned out' with zeros, otherwise the FS image grows
and eventually doesn't fit on the CD any more.

Unfortunately, the tool originally used (partimage -e) only works on i386
which isn't much use on amd64 and ppc.

The possibility of chattr setting '-s' on every file in the image wasn't
really an option as this same image is the one used whilst running the
LiveCD and (in the next version) will also be the installed image used by
UbuntuExpress:

  http://udu.wiki.ubuntu.com/UbuntuExpress

	-Paul
-- 
It sometimes snows here.  Nottingham, GB