Subject: Re: user-land file systems
To: VaX#n8 <>
From: Stefan Grefen <>
List: tech-kern
Date: 06/19/1995 13:39:41
In message <>  VaX#n8 wrote:
> Also, I'd like to see some kind of callback into user space (daemons?) to
> handle userland debugging of filesystems.  I know they'd be slower, but they'
> d
> be less like to crash your system (and easier to debug), and there really
> isn't any reason IMHO why a user can't access a file of hers as a fs hierarch
> y
> of her own design if she really wants to.  What do you people think?

There is a emerging standart (I don't have the actual draftnumber handy),
which deals with this issue. It's called DMAPI (previous name DMI(G), but was
renamed due to acronym collison with the desktop mamangment interferace (group))

But be careful there are lots of interesting race-conditions out there :-))
(I know firsthand, Convex has a similiar interface in the filesysetem for years
now, and we still find new 'effects' with it).
But loopback NFS can be as bad (at least on multiprocessor systems).

But I think it's a project worth doing, (even to only build an 
unlimited filesystem by automaticly migrating to tape or other machines).


> -- 
> VaX#n8 (vak-sa-nate) - n, CS senior++ and Unix junkie -
> u
> Deal with evil through strength, yet encourage good through trust.    - PGP m
> e

Stefan Grefen                          Convex Computer GmbH, Frankfurt, Germany		       Phone: +49-69-665270
fortune: "You can't make a program without broken egos."