General dependencies discussion (was: ARTICLE - ESR gives up on Fedora)

[Bill McGonigle]

On Feb 26, 2007, at 20:46, Nigel Stewart wrote:

> If all of this sounds deluded, I am relying on you all here
> to point out the show-stopping flaw... :-)

I think it's a good idea.

As a transition mechanism you might think about writing an RPM or deb  
filesystem.   Taking the RPM instance:

   mount -t rpmfs /var/lib/rpm /rpm

   ls /rpm/htop
   current@ 0.6.4-2.fc6/ 0.6.5-1.fc6/

   ls -l /rpm/htop/current
   lrwxrwxrwx 1 root     root           32 Feb 27  2007 current ->  
0.6.5-1.fc6


   ls -R /rpm/htop/0.6.5-1.fc6/

   /rpm/htop/0.6.5-1.fc6/usr/bin/:
   htop

   /rpm/htop/0.6.5-1.fc6/usr/share/applications:
   htop.desktop

   /rpm/htop/0.6.5-1.fc6/usr/share/doc/htop-0.6.5:
   AUTHORS COPYING ChangeLog INSTALL NEWS README

   /rpm/htop/0.6.5-1.fc6/usr/share/man/man1:
   htop.1.gz

   /rpm/htop/0.6.5-1.fc6/usr/share/pixmaps:
   htop.png

and you could then populate the 'traditional' filesystem with  
symlinks.  It's not ideal, but it's a start.  I stole that part from  
the Fedora /etc/alternatives mechanism.

Now, if an RPM was just a cpio archive you'd be done.  But you have  
pre- and post-install scripts that get run, mechanisms for helping  
with /etc/ configuration, etc.

How do you get away from /etc?  To be thorough you'd need read/write  
parts of the RPM and checksummers that know how to ignore those.   
Might as well include versioning of those read/write parts since  
you're starting from scratch.

Also, cpio isn't a random-access format like ZIP, so you have to  
redefine RPM.  I'd probably re-use the .jar format - I think it has  
everything you're likely to need.

Cool idea, keep at it!

-Bill

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