Subject: Re: [netatalk-admins] DIDs - an idea -or- I didn't read the AFP specs completely yet
From: Sak Wathanasin (sw@nan.co.uk)
Date: Thu Apr 16 1998 - 18:30:38 EDT
In reply to Gary E. Bickford's message of the 15/04/98 at 19:03 -0500,
> At 5:08 PM -0500 4/15/98, Donald L. Nash wrote:
> >This won't work and cannot easily be made to work because DIDs are only 32
> >bits long. I looked into using inode numbers combined with major and minor
> >device numbers to create an inode-based DID that worked for volumes which
> >span filesystems, but had to give up on it because inode numbers are 24 bits
> >long and major and minor device numbers are each 8 bits long. I couldn't
> >figure out a way to cram 40 bits into 32 without the possibility of
> >collision. :-)
>
> Yeah, I didn't work out the details (mainly 'cause I don't know whereof I
> speak :) - but your last point reminds me of gray coding, which does just
> that, and the result is always unique, though not sequential. I forget how
> it works...
>
> GEB
Isn't there a more basic problem than craming 40 bits into 32? inodes get
reallocated, don't they? What happens when you delete a directory and create a
new one straight away?
Sak Wathanasin
Network Analysis Limited
178 Wainbody Ave South, Coventry CV3 6BX, UK
Internet: sw@nan.co.uk
Phone: (+44) 1203 419996 Fax: (+44) 1203 690690
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