the 16 vs. 32 bit
On Mon, Oct 07, 2002 at 03:52:49PM -0700, Sam Leffler wrote:
...
> Sounds to me like the real issue for you is insuring unique m_tag_id values.
> We're certainly less likely to have collisions with a 32-bit value than a
> 16-bit value and expanding this way gives you your "field ID" too. I guess
> the question I have is whether the existing API's that search only by
> "cookie" are sufficient for your needs. If so then I'm ok with changing
> things. Otherwise we have an API incompatibility with openbsd that I'd like
> to avoid.
i wonder what do we gain by moving to 32 bit m_tag_id -- because there is
is still no strict guarantee that we have no conflicts
if people randomly choose "cookies", and also, using the same reasoning
for allocations one could argue that having the cookie chosen as the number
of _days_ since the epoch, will still give low conflict probability while
still fitting in 16 bits.
Also, those modules that require one or a very small number of different
annotations (e.g. all the ones currently using m_tags) would just need
the "cookie", whereas others with a large set of subfields could as well
consider the field_id as part of the opaque data.
cheers
luigi
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Luigi RIZZO, [EMAIL PROTECTED] . ICSI (on leave from Univ. di Pisa)
http://www.iet.unipi.it/~luigi/ . 1947 Center St, Berkeley CA 94704
Phone: (510) 666 2988
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