Re: should one single search be able to encompass several databases?

[Stig Venaas <Stig.Venaas@uninett.no>]

On Thu, Jul 19, 2001 at 01:28:12PM -0700, Mark Whitehouse wrote:
> I like Kurt's proposal this is exactly what I have been looking for.  How is
> this different from back-meta?
> 
> I would be willing to contribute some resources (i.e. development time) to
> help get this done...  Who if anyone is working on this and what is the
> state of the code?

I like this as well. For filesystems I like very much the stackable
filesystems you have in some BSD implementations. You can mount several
filesystems/layers on top of each other, requests are going through the
top layer downwards, and data/responses travel upwards. On the way down
you can modify requests and on the way up you can modify data/responses.
Something similar might be possible for our backends? For filesystems
this can be used for several things:

o Null filesystem, sort of a symlink, mount something in one place
  in the tree at another place

o Union filesystem, merge data from different filesystems, for
  instance first mount a read-only media cd-rom/nfs and on top a
  harddisk filesystem so that if you write data it gets written
  to the harddisk. For LDAP this could perhaps be a proxy where you
  can add some extra objects or write things to the proxy. Well, it's
  not really a plain proxy then.

o Add ACLs on top of a filesystem without it

o Add compression, encryption capabilities

For LDAP one could perhaps implement layers for charset-conversion
or rewrite attribute names etc. Like back-meta today?

Stig