[cap-talk] Price of resource accountability

[Matej Kosik]

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Baldur Johannsson wrote:
> Curiously enough I have been thinking/experimenting a bit with exactly
> this issue.

Likewise.

> 
> Three kinds of resources for an protection domain come up in my mind:
>   1. memory ( for storing programs both text and state )
>   2. cpu-time ( for running an protection domain )
>   3. inter protection domain messaging ( to prevent flooding )
> 
> Both 1. and 2. are familiar to anyone who as studied KeyKos/Eros/Capros as
> they can be achieved by sub-spacebank and sub-meter respectively.
> But what about 3.? I havent seen it used/mentioned so far except in
> the Agorics Inc.
>  paper titled "Digital Silkroad" under the concept of "postage".

I do not think that problems (1) and (3) are inherently separate. At
least in my current attempt to address this problem for Pict

	http://altair.sk/mediawiki/upload/4/48/Memics2008.pdf
	(work in progess)

these two problems are addressed at once.

Some details are in the article. Although I do not regard the
proposition very trustworthy until I implement it and test it. But I
have the belief that it can be solved.

I am somehow hesitating to turn to schemes described in the Digital
Silkroad article---especially in non-distributed and closed environment.
There must be a simpler solution. Although in a distributed environment
they seem inevitable (even though they are beyond my imagination how to
implement them).

> 
> So I ask you(plural) this: are these three types of resources inter-fungible?
> If that is the case I suggest that an third type of datum primitive (besides
> capabilities and normal bit pattern datums) be added to both protected
> domain state
> and messages: some sort of an quota currency ( basically an big number
> say 256 bit one).
> 
> Also that the additional behaviour would be added:
> The kernel deducts x amount from an protected domains quota currency
> amount when said domain is acquiring more memory, creating other
> domains and sending messages.
> And such operation would fail (with indication) if the domain doesnt
> have enough of the quota currency.
> The kernel adds x amount to an protected domains quota currency when
> it receives an
> message from another domain and releases memory.
> 
> Quota currency would, as noted above, also be part of every message
> giving the option of
> a sending domain passing more of it to receiving domain if so desired
> by the programmer at
> the time.
> 
> If anyone is interested in a spec for capForth Actors I clobbered
> together then dont hesitate
> to ask for it. Though here is a fair warning: it is an documentation
> written by an programmer
> for himself and assumes familiarity of the Actor Model, capabilities,
> Forth and Dual Stack Machines.
> 
> I hope this post of mine is pretty free of rambling and need for clarifications.
> Cheers
> -Baldur
> _______________________________________________
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> cap-talk at mail.eros-os.org
> http://www.eros-os.org/mailman/listinfo/cap-talk
> 

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