DLoop comments

[Phillip Susi]

I wasn't sure if I should comment on this by adding to the wiki or here, 
but I decided to go with here.

I have read over this Wiki proposing changes for ubuntu express, and it 
seems overly complex to me.  I have some comments and a much simpler 
proposal.

One issue this Wiki discusses is freeing unused cloop blocks.  As it 
says, this is easily done when initially building the cloop image by 
running a utility to zero out all unused blocks.  Once the livecd is up 
and running, the solution to this problem seems that it should be as 
simple as having the filesystem zero out freed blocks, and have the 
snapshot device mapper notice when it gets an all zero block written to 
a page that has been COW'd it can discard the memory.  That should be a 
rather simple thing for the mapper device to do.


The rest of the Wiki seems to be about the debs.  It seems to me that a 
simple solution would be to modify dpkg so that it can remove the 
binaries from the .deb once installed.  Then when you go to install the 
package on another filesystem, it can simply pull the binaries back from 
where they were installed to the first time.  That would avoid the 
duplication of binaries in both the .deb and the livecd filesystem, and 
shouldn't be very difficult to implement.

What do you think?