Subject: [netatalk-admins] persistent DIDs

From: Michael M Han <[email-masked]>
Date: Mon, 13 Apr 1998 13:12:51 -0700

Okay, persistent DIDs have become *very* desirable to me and I'm
trying to find a short-term solution (even if it's limited) until
persistent DIDs can be issued The Right Way, which I'm assuming will
take quite a while. I'm running netatalk w/ asun's 18.2 patches on a
Solaris2.6 SparcStation2.

Is anyone aware of ways to get persistent DIDs from netatalk? The only
things I could think of, HFS-mounted filesystems, which I'm assuming
store DIDs natively, and maybe AFS (which produces an FNUM-analog but
I'm not sure about DIDs), aren't supported by netatalk from what I can
tell. Or, to be more clear, netatalk doesn't seem to care if the
filesystem is willing to provide a usable DID and generates a
non-persistent one as it goes (from my reading of
etc/afpd/directory.c). This does make a certain sense since it's all
well-and-good for a single filesystem to be providing real DIDs but
that doesn't help a volume spanning multiple, heterogenous
filesystems...

Can anyone think of any ways to get my afpd volumes to provide
persistent DIDs in the short term? Copious thanks to anyone who can
help me out here.
_____
Michael Han ([email-masked])                     voice: (415) 502-7542
Interactive Learning Center Consultant                        (415) 476-4309
San Francisco, California 94143-0840                     fax: (415) 476-4653
"I had lately learned that another way of writing FALL IN LOVE is WALK THE 
PLANK." - Jeanette Winterson

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From: Jonathan Peterson <[email-masked]>
Date: Tue, 14 Apr 1998 09:00:04 +0100

>Okay, persistent DIDs have become *very* desirable to me and I'm

*Unknown Acronym Alert!!* Can someone tell em what a persistent DID is?

Thanks,

--------
Jon Peterson	[email-masked]	+44 (0)171 613 5300

Give me liberty or give me death or give me coffee.

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From: Michael M Han <[email-masked]>
Date: Tue, 14 Apr 1998 09:29:27 -0700

Oops, sorry about that. Directory IDs are an inode-ish unique number
assigned to each directory on a Macintosh volume. The are complemented
by FNUMs (File Numbers?) for files. Anyway, netatalk currently has
some trouble with DIDs, which causes odd problems with volumes shared
by afpd.

Essentially, a Macintosh requires that DIDs be permanent, but due to
various problems with providing them in netatalk, they aren't
permanent (the way the numbers are assigned has very important
differences from inode numbers assigned on Unix filesystems). As a
result, Mac software that's looking for things on afpd volumes
sometimes can't find what it's looking for. It's looking for a DID it
expects hasn't changed, but afpd *has* changed the DIDs. There are
better (and maybe more accurate) explanations of the situation in the
list archives and maybe in an FAQ.

Previously...
>*Unknown Acronym Alert!!* Can someone tell em what a persistent DID is?
_________
mike ([email-masked])
Garlic gum is not funny
 - The collected wisdom of Bart Simpson

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From: Edan Idzerda <[email-masked]>
Date: Tue, 14 Apr 1998 15:49:45 -0400 (EDT)

> some trouble with DIDs, which causes odd problems with volumes shared

I believe that Netatalk makes up DIDs that are only consistent 
during each session.  So, it doesn't really have trouble with them, 
it just gives you trouble if you expect your alias to last between
sessions :)

I think that CAP uses some extra process to manage them.  I believe
that DIDs have been discussed on this list before, with no resolution
that I can remember.  If it were easier to search the netatalk-admin
archives I'm sure one could find it.

So yeah, persistent DIDs would be a nice thing, but it's going to take
a very motivated individual outside of umich to get it done anytime 
soon, as I don't believe its a priority for them.

- edan

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From: Bill Stewart-Cole <[email-masked]>
Date: Tue, 14 Apr 1998 14:56:44 -0500

>*Unknown Acronym Alert!!* Can someone tell em what a persistent DID is?

Something that has been DONE and will NEVER be undone?

(Just kidding)

DID = Directory ID. MacOS expects every directory to have a permanent
unique ID because this allows for the beloved File System Specifier data
structure (aka FSSpec) to do magical file tracking even if you do things
like dismount volumes and re-arrange directory structures. The FSSpec and
it's descendants in the Alias Manager are a large part of why Mac users can
be so smug about not knowing or caring about full pathnames and
re-arranging folders.

Netatalk doesn't preserve DID's and so you can end up with programs that
normally perform magic with FSSpec's and the Alias Manager getting quite
confused. Quark, as an example.

----
Bill Stewart-Cole
Finan Publishing