Re: CTree/ETree

[David.Empson@bbs.actrix.gen.nz]

In article <jmk3.729494778@crux1.cit.cornell.edu> jmk3@crux2.cit.cornell.edu (Jay Krell) writes:
> >From: David.Empson@bbs.actrix.gen.nz
> >Subject: Re: CTree/ETree
>  
> >CTree is the []
> >ETree is the []
>  
> >I wasn't aware that CTree and ETree actually appeared in the catalog
> >tree, and I didn't think they had filenames.
>  
> How did you know about CTree and ETree? Is it obvious with some knowledge of
> HFS?

I've read the HFS documentation in Inside Mac Volume 4.  The Catalog
tree and Extent tree are special files, in that their first extent is
specified by a field in the volume information record (block 2).  If
they occupy more than one extent, there will be further entries in the
extent tree.

I don't understand enough about HFS's B-tree structure to go into more
detail than this, at present.  I tried looking through an HFS volume,
going by the description in Inside Mac, but couldn't fathom the
indexing method.  It seemed to bear no relationship to the documentation.

> Nifty List shows them as open files, but I don't think that means they are
> in the catalog tree. Maybe it is just some convenience for the FST to have them
> as open files. I'm ignorant in this area, though.

Probably just for convenience.  I think the HFS FST has made up the
filenames just to be consistent.  I wonder what happens if you try to
close them?  :-)
-- 
David Empson

Internet: David.Empson@bbs.actrix.gen.nz    EMPSON_D@kosmos.wcc.govt.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand