Re: Re: Removing FIred admins

[Valdis.Kletnieks () vt edu]

On Sat, 14 Feb 2004 09:27:30 +1300, Steve Wray said:

> DRM (Digital Restrictions Management)could,effectively, 
> make DRM compliant PCs such that there are programs
> that they cannot run, hence they would not be Turing complete.

Well.. actually you got that backwards.

A machine can be Turing complete and still not be able to run every
possible program - that was the point of the Turing halting problem
(which happens to be the same thing as Godel's Theorem phrased differently).

For it to be Turing-*incomplete* there have to be almost no programs that
it can run.  Basically, if it has enough smarts to run a simulator of a
Turing Machine, it's Turing-complete - and all you need for THAT is a
decrement instruction, a 'test and skip next if zero' instruction, and
a branch instruction.

One guy even managed to get rid of conditional branches/skips:
http://page.mi.fu-berlin.de/~rojas/misc.ps

On the other hand, it's quite possible to end up looking like a WebTV,
where there *isn't enough* user-accessible functionality to become
Turing-complete, which is (a) what the DRM crew wants and (b) what I
think you actually meant to say... :)

> I didn't mean that DRM would help in firing sysadmins.

It would probably suffice against the average MCSE. ;)

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