Shadow filesystems [was Re: Pair donates 20,000 to Poul-Henning Kamp??]

[Brad Knowles]

At 5:43 PM +0300 2004/04/16, Jari Kirma wrote:

>  I played with the idea of "reliable undelete" functionality some time ago.

	After a catastrophic wipeout when I was a student at the 
University of Oklahoma about 20 years ago (causing me to work 36 
hours straight to re-create all my hard work), I created a set of 
shell script tools to replace the "rm", "mv", "cp", etc... programs 
with something that would use a "~/.Trash" directory and then 
compress the files, etc....  When I first created these scripts, they 
were very popular, and widely used by the student community.  IIRC, I 
posted a fairly final version of those scripts to comp.sources.*.

	ECN staff had a disagreement with me over these tools, thinking 
it unwise for people to get used to the "new" behaviour, which might 
lead them to get seriously screwed when they used "rm" somewhere else 
and it didn't act in the way they expected.  However, it wasn't until 
after I had another massive wipeout (this time using vi to write a 
file into the wrong filename), that I decided that I agreed with them.

	So, I removed the scripts from my bin, although others could 
always go to the newsgroup archives and pull down their own version 
if they wanted.  I don't think anyone did.


	If you really want to make something like this work, you have to 
cover all possible avenues of destruction, not just creat(), 
unlink(), and rename routines.  Introduce a real filesystem 
versioning scheme, and I would gladly welcome your work.

	But please don't violate POLA, and please don't help to create a 
different set of user expectations that would cause users to get 
seriously hurt if/when they're on another OS.

-- 
Brad Knowles, <brad.knowles at skynet.be>

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
     -Benjamin Franklin, Historical Review of Pennsylvania.

   SAGE member since 1995.  See <http://www.sage.org/> for more info.