Re: FYI: Directory definitions document

[Ed Gerck <egerck@nma.com>]

Harald Tveit Alvestrand wrote:

> FYI, the following draft just came out:
>
>   Title : Definitions for talking about directories
>   Author(s) : H. Alvestrand
>   Filename : draft-alvestrand-directory-defs-00.txt
>   Pages : 6
>   Date : 21-Oct-99
>
>  Comments welcome!

Harald:

The draft says:

- Information: Something for which one can imagine multiple worlds
  where the item in question has different values. The fact of which
  particular value is true for this world is information.

  This definition is extremely abstract, and intentionally so, but on a
  philosophical level, it's closely related to Shannon's signal-theory
  definition of "information".

But, this is not correct. In particular, if  "The fact of which particular
value is true for this world" is information then information has zero
suprise -- hence, it cannot be Shannon's information.

In other words, information in Shannon's sense is that which is not
expected. If the particular value is true for this world then that value
is expected and has zero information.  Which contradicts the draft's
definition.

I suggest the draft does not redefine information.

I also would tend to think that notification services are built around
directories, but they do not define a new class of directories.  The
inclusion of notification services is thus IMO not necessary. Other
terms seem also not to be necessary (subscription) to define the
basic functionality needed as a common building block.

So, I suggest that the draft should, in general, not redefine or even  define
what is not needed.

Cheers,

Ed Gerck