Subject: Re: kern/1781: 'magic' symbolic link expansion
To: None <netbsd-bugs@NetBSD.ORG>
From: Ty Sarna <>
List: netbsd-bugs
Date: 11/24/1995 03:54:30
In article <>,
Peter Seebach  <> wrote:
> That's what HP says about cdf's, and all they did was break find, cpio,
> tar, and the like, and get abused.  I never saw them do a whole lot of
> good.

But CDFs are different. If you want to argue against magic components,
fine, but how about arguing on their own mertis (or lack thereof) rather
than some other scheme's? Arguing that magic components are bad because
CDF is bad is a strawman.

> >I doubt the overhead is much more than any other "special case" processing
> >happening now, and the lookups could be cached just as easily as any other.
> *what* special case processing?  I don't see any yet.

Uh, how about symbolic links? Which, incidentally, broke a lot of
things. I've never seen breakage of magic components under AFS (though
AFS breaks some things for other reasons)

> But mostly, why should we charge every user of every system everywhere
> *anything* for this feature?

Could be said for almost any feature.

> I don't like the idea of losing kernel space and processor time to this
> without more study of what we're trying to accomplish, and how we want
> to go about it.

The processor time has got to be quite negligable. I don't think two
more instructions (probably) per uncached lookup is going to be
really significant. Especially compared to the overhead of the

> A new type of file, which looks like a symlink, but has extra frills,
> might make more sense; we already have established that new file types
> will show up.

So you're arguing for something *more* like CDF's???

> I just dislike the idea of putting more clever awareness into symlinks.
> What next - environment variables?  Inline tcl or perl?  Hmph.

Absolutely right. And a merged VM/buffer cache is bad becauase next it
will lead to calls for merged stdio buffers as well, right?

> Of course, I'm a bit of a purist; I still think that the net should be
> mounted as a filesystem, and that ifconfig should just echo commands
> to the special files that read them.  The filesystem model is a great
> beauty, and I don't think we should fill it with cruft for short term
> convenience.

This sounds like the arguments against symlinks.