[e2e] end of interest

jonathan@dsg.stanford.edu jonathan at dsg.stanford.edu
Fri May 9 19:14:59 PDT 2008

In message <48247C79.70103 at isi.edu>Joe Touch writes

>John Day wrote:
>> At 16:23 -0400 2008/05/08, Craig Partridge wrote:
>>> I don't think it said don't bother touching TCP and below so much as said
>>> they don't matter.  That's certainly what Van said in a more recent talk.
>>> And I think it is right -- if you think you have a game changing paradigm
>>> that can work over existing stuff but might work better over new stuff,
>>> focus on your core idea -- if it works, the rest of the network will
>>> morph to support it.
>> Some time ago, Microsoft had the same idea about dealing with having
>> half an operating system.  Didn't work for them, not going to wor
>> here.  Overlays are building on sand, or trying to sweep the mess under
>> the layer.  They can't fix what is fundamentally an incomplete
>> architecture.
>Does that go for virtual memory too?
>IMO, overlays are as integral to networking as VM is to memory -
>something we didn't put into the original architecture, but isn't a
>stop-gap either.
>VM, e.g., was originally to handle memory capacity limits, but has other 
>benefits that persist even when RAM is plentiful:
>	- providing a linear, contiguous memory view to processes
>	- sandboxing processes from each other
>Overlays have very similar benefits to networking. [...]

[[Caveat: on historical matters, I defer, before the fact, to those
  who were there before me, nevermind those  there at the time! ]]

Hi Joe,

I don't think that's a good analogy. The contemporary literature -- as
collected in Structured Computer Organization: Bell & Newell; or Bell,
Newell and Siewioriek -- shows that sandboxing of process memory and
"linearization" of process memory predates the Atlas and its
"one-level store". Base/bounds registers go back much earlier, and
provide both sandboxing and relocation.  Hm. Didn't sharing of address
spaces, via segments also predate demand-paged virtual memory?

Last, As Seymour Cray put it, "Virtual memory is you don't have".
Does this this VM ==> Overlay networks analogy stretch as far as:

   "Overlay networks you don't really have"?

Joe, I'm guessing you'd disagree.  Personally I don't have a stake
either way. But I'm curious: if the question is posed that strongly,
does anyone care to defend it?

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