[e2e] a means to an end

David P. Reed dpreed at reed.com
Tue Dec 2 10:08:35 PST 2008

Objects != information.   No need to objectify information anymore than 
need to objectify women.  :-)

Regarding flooding - the alternatives not so black and white as you make 
them out to be.

Search can scale rather dramatically, under the same conditions that 
routing can scale: when things don't move.

The difference is that search doesn't require that the pre-condition of 
static placement be satisfied... a good search strategy adapts its work 
effort to conditions.

Instead of flood first, one could do depth-based search from a landmark 
near the last appearance known, if given a network that is relatively 
static, where things move slowly.

Algorithms are great things.  They can be designed to adapt, while still 
doing well in simple cases.

So "flooding" seems just a straw man argument made by those who don't 
want to consider adaptive algorithms.

David Andersen wrote:
> Interesting discussion.  I sense something fundamental here in the 
> needles vs. haystack side of things:  one can find hay easily without 
> needing to embed location at all, b/c you can flood to find it and 
> expect to find it soon.  For scalability, though, needles need some 
> well-defined rendezvous point.
> That rendezvous point eventually needs to map to a physical 
> realization that stores, at minimum, a mapping that tells you where to 
> get the data you're interested in.  Or could store the data itself.
> This is, of course, assuming that the # of data objects in the 
> universe is substantially larger than the # of globally, independently 
> routable objects in the universe.  Which is probably a reasonable 
> assumption for the medium term.
>   -Dave
> On Dec 1, 2008, at 11:53 AM, Craig Partridge wrote:
>> Hi Dave:
>> So fine, call it datum or message -- the point is that some things that
>> are desired have a single current instance.  That instance may get 
>> replicated
>> eventually, or not, depending on context.  It may be that you can
>> retrieve something similar from other, more widely available,
>> sources/instances/etc.
>> But you haven't responded to the point I made which is that when you
>> want something that is rare, what I've discovered is all systems to
>> date embed location.  If I'm understanding your note, you think I'm
>> saying there's a reference copy/instance that we all must go back to
>> ala the Grail (nope, that's not what I'm saying) or that I'm otherwise
>> intentionally making things rare.  Instead I'm saying, when something is
>> rare (1 instance/instantiation/whatever in the world -- and, by the way,
>> I care about such cases as I used to be a medievalist and occasionally
>> was probably the first person to see a document since it was written 700
>> years ago), I've found that every information retrieval system 
>> (including
>> Van's) embeds a location.
>> Thanks!
>> Craig
>> In message <49340902.2050400 at reed.com>, "David P. Reed" writes:
>>> Interesting.
>>> Your presumption that information is a matter of copies, and that "sole
>>> copy" is a well-defined term, suggests a fundamental difference in our
>>> understanding of the word "information".
>>> Had you used the word "datum" or "message" (two human constructed
>>> concepts), I might agree.  But "information" is not a synonym for 
>>> either
>>> term.  Both are *representations* or *instantiations* of information.
>>> A piece of paper with a number printed on it may be the "sole instance"
>>> of a printed piece of paper with that particular representation of
>>> information.   But if that number represents (say) "the total net value
>>> of my bank account on Dec. 1 2008", it is not at all the only "copy" of
>>> information.
>>> Information typically exists independent of form or 
>>> representation.   It
>>> is a constructed, calculated, computed thing.  It doesn't exist
>>> independently, nor does it exist in sole form.
>>> Yes, I could agree with you that if information were forced to exist in
>>> "single copy" form, it would require some complex and amazing procedure
>>> to copy that piece of information into another place.  But, once 
>>> copied,
>>> it would be smeared across half the universe.  (or alternatively you
>>> could decide, since "place" is really not a very easy-to-define term,
>>> that the information is still in one place, but the universe has now
>>> collapsed significantly, because all the places "containing" (whatever
>>> that means) the information would be "the same place").
>>> But independent of that: why is any information system designed to have
>>> data in a "sole copy"?   Van asks this question, and he is wise to ask
>>> this question.  Most computer systems work by having vast numbers of
>>> copies of data. We constantly see most information representations used
>>> in computation in the form of cached data.
>>> It seems to me that it is a pure fetish, perhaps conditioned by
>>> training, to posit that most information is represented by single
>>> copies.  That way lies "brittle" failure-prone engineering.
>>> Let a thousand representations bloom.  Many of them will be copies of a
>>> datum.  Others will be computable recovery algorithms - some of which
>>> invent an abstraction called "location".   But even that abstraction
>>> called location is not a "place" in the sense of a 4 dimensional 
>>> spatial
>>> metric based coordinate system.   I address a piece of paper by its
>>> title, not its current location in the file folder on someone's desk.
>>> Craig Partridge wrote:
>>>>> Our dear friend, Van Jacobsen, has decided that layering "where" 
>>>>> under
>>>>> "what" with regard to data is neither necessary, nor a good idea.
>>>>> I agree: confusing the container with the information it happens 
>>>>> to hold
>>>>> is a layer violation.  Information is not bound to place, nor is 
>>>>> there a
>>>>> primary instance.  Information is place-free, and perhaps the idea 
>>>>> that
>>>>> there must be a "place" where it "is" is an idea whose time should 
>>>>> pass,
>>>>> and the purveyors of that idea as a holy writ (the OSI layering) 
>>>>> retired
>>>>> to play golf.
>>>> Hi Dave:
>>>> Much as I'd like to believe this particular theory (as it is nice, 
>>>> clean
>>>> and pretty), practical considerations suggest we're not there.
>>>> I've talked with some of the folks working on information and seeking
>>>> to make information place-free, and the answer, so far, that I've 
>>>> gotten
>>>> is that you get part-way there.  If the information is popular or
>>>> "nearby" then there are mechanisms that can be viewed as place-free 
>>>> (and
>>>> a good thing -- it means that the more popular a piece of 
>>>> information is,
>>>> the easier to get easily and perhaps from somewhere locally).
>>>> But if you ask about retrieving an uncommon piece of information then
>>>> you discover "location" crawls out from under the covers.  That is,
>>>> if you ask the question "where do I find the sole copy of item X", you
>>>> learn that somewhere hidden in the name of X is a location -- perhaps
>>>> of X or perhaps of a rendezvous server that knows where X is -- but
>>>> there's the location of something buried in there.
>>>> Thanks!
>>>> Craig

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