Proposal: cache directory tagging convention

[Bryan Ford]

Hi!  I've been referred to this list as the most appropriate place to discuss 
an idea I've recently written up and posted here:

	http://www.brynosaurus.com/cachedir/

The short version: Many applications, especially web browsers but also others, 
create and maintain cache directories of various kinds, often buried 
somewhere in users' home directories, in which they store automatically 
regenerable content that is useful for performance but has little or no 
archival value.  I propose a simple convention by which applications could 
consistently tag their cache directories so that backup, archival, and data 
management software can easily (if so configured) recognize and auto-exclude 
them from backups and such.  In particular such a convention could 
substantially reduce unnecessary backup storage and/or network bandwidth 
consumption caused by backing up users' web caches, which tend to be sizeable 
and under constant churn (thus defeating incremental backup mechanisms), yet 
semantically useless.

While very short and simple in its current preliminary version, the proposal 
is written with the possibility in mind of allowing future extensions leading 
to the possibility of providing richer systemwide controls over application 
cache storage.  I would greatly appreciate your ideas and feedback.

Thanks!
Bryan