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Talk:Trusted computing base

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This is an old revision of this page, as edited by Heiser (talk | contribs) at 05:36, 19 February 2008 (Lampson isn't the original source of the term). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.





hi anyone I just want to know how command control communicatiob and intelligent systems[C3I] actice as a main part of the information technology sector rather than defence. please comment any idea

thanks

Not sure how to fix this

From the article:

barring any reason to believe otherwise, a computer is able to do everything that a general Turing machine can.

This is wrong for two reasons:

  • It is a fundamental given of computer science that no real computer is able to do everything that a general Turing machine can. To be able to do so would require infinite amounts of memory, for instance.
  • It isn't even relevant. A General Turing Machine is a model of computational ability, which is not even approximately related to satisfaction of security constraints. A perfectly behaving, sandboxed environment (e.g. like a flawless implementation of javascript in a web browser) is capable of emulating a general Turing machine just as well as any computer (i.e., it has limitations based on the size of memory available to it, but can otherwise perform the same calculations). This doesn't mean that it is insecure.

I'm not sure what model should be used to describe a computer without security restrictions, but any Turing-machine related model is not appropriate for this. JulesH 14:36, 3 May 2007 (UTC)[reply]

Historically incorrect

The article credits a 1992 paper by Butler Lampson et al for the term TCB. In fact, it was used 11 years earlier in John Rushby's famous separation-kernel paper [Rushby, 18th SOSP]. This might be the original definition, but I'm not sure. (I'll ask John next time I see him.)