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Re: Re: [colorforth] DARPA takes aim at IT sacred cows


From: "Samuel A. Falvo II" <kc5tja@xxxxxxxx>
>>http://www.eros-os.org/essays/ACLSvCaps.html

>I've read it, and their arguments contradict the 
>simple mathematical proof that ACLs and capabilities 
>are semantically equivalent.

But they're not -- they're opposite sides of the same
matrix. Oh, okay, I'll let you finish your paragraph:

>If capabilities represent the vertical columns on a 
>permissions matrix, then ACLs represent the horizontal 
>rows.  They both express *exactly* the same level of 
>information.

ANYHOW, this is true as far as it goes: but it doesn't go
far enough. Both ACLs and capabilities can express the same
thing when you look at a frozen moment of time, but both
behave very differently in a real, running system; and this
is just what you'd expect from two different ways of looking
at the same thing.

The nice thing about capabilities is that they're a natural
way for computers to operate. A pointer is a capability.

> Samuel A. Falvo II

-Billy



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