[geeks] Re: [rescue] RE: Absolutely nothing to do with 'Small schools.& elections'

[Ken Hansen]

See below, my responses will have ** infront of them...

Ken

-----Original Message-----
From: Joshua D. Boyd [mailto:jdboyd at cs.millersville.edu]
Sent: Wednesday, June 20, 2001 4:19 PM
To: 'geeks at sunhelp.org'
Subject: RE: [geeks] Re: [rescue] RE: Absolutely nothing to do with
'Small schools.& elections'


OK, I'm with you so far (and your are acurate according to my much more
recent taking of Computational Models).

** Nice to know it hasn't changed, and my memory hasn't faded (yet)...

So, we can have a display that indicates the state.  However, the display
on my notebook if front of me doesn't tell me the internal state of
the machine. Likewise, I have an eithernet device, and it's output
doesn't indicate the state of my machine.

** Either net? Is that a dual=port NIC? ;^)

** Think IMSAI 8080 or SWTP 6800 machine from the 1970's that is a display too...

So, the problem at hand is:  Is it possible to remain true to the Turing
machine while having a display and ethernet.  Now, we could map the
display and ethernet packat buffer to the tape, and create some states
that do things like update the display to the new display buffer, or send
the current packet buffer.

** Why not? You have just overloaded the operation of
** the symbols to include doing things that are not
** reflected on the tape - is that a deal killer?

The problem is that the turing machine doesn't have direct memory
indexing.  All it knows is that it can move back a byte or forward a byte,
and that presumably there are infinite bytes in either direction.

** What do you call moving the tape? The tape is
** the memory, that was the inovation/value-add
** of the Turing machine model...

So, how would be know where how to find the display and packet buffers?

** They indicate the state of the machine, why have buffers?

On a like note, in string lamda calculus, is there a solution to this
problem?  Just represent the display as a really long list passed as part
of a variable?

** You've lost me - Calculus eluded me, that is
** one reason why I have a Humanities degree!

I know what lamda calculus is, but it wasn't covered at all in school, so
I know very little about it.

** You are one up on me!

--
Joshua Boyd

On Wed, 20 Jun 2001, Ken Hansen wrote:

> The definition of a turing machine is that you have a box, and a tape running through it, infinitely long in either direction. The tape is one symbol "wide" (think movie negative).
> 
> The turing machine starts in an initial state. Then, based on the symbol/value of the frame of the tape inside the machien, it can either move to the left or right a discrete number of frames, and mark the current frame with a new value.
> 
> As the machine dances through these operations, it will be in different states, most likely related to the last symbol read from the tape.
> 
> Nothing I am aware of says the turing machine can or can not have a display indicating the current state of the machine (when you work through examples in school, you typically have a table that you fill in with the state of the machine at various points in the processing of the tape.).
> 
> That is about the sum total of my memory of turing machines, any more details will require me to pull out my Discrete Mathematics text from 15 years ago...
> 
> Now, the Turing test, is a whole different thing... ;^)
> 
> Ken
> 
> -----Original Message-----
> From: Joshua D. Boyd [mailto:jdboyd at cs.millersville.edu]
> Sent: Wednesday, June 20, 2001 3:58 PM
> To: 'geeks at sunhelp.org'
> Subject: RE: [geeks] Re: [rescue] RE: Absolutely nothing to do with
> 'Small schools.& elections'
> 
> 
> So, would the display be part of the tape, or is each display state a
> machine state?  Would these just be a machine state for each pixel in the
> display?
> 
> --
> Joshua Boyd
> 
> On Wed, 20 Jun 2001, Ken Hansen wrote:
> 
> > Display? We couldn't even imagine a computer being able to display anything, we just "knew" what was going on in the game... Geez, anyone can play if you can just see the game in front of you... ;^)
> > 
> > Ken
> > (Seriously though, I know of no reason why a turing machine couldn't have a display - it has a state, and it needs to communicate it to the user, so I would imagine in the strictest sense it would have to have a display, but the display may not be of a form familiar to today's "pampered" users, maybe a series of blue LEDs, or a scrolling LED array, like those found in grocery stores... ;^)
> > 
> > -----Original Message-----
> > From: Joshua D. Boyd [mailto:jdboyd at cs.millersville.edu]
> > Sent: Wednesday, June 20, 2001 3:18 PM
> > To: 'geeks at sunhelp.org'
> > Subject: RE: [geeks] Re: [rescue] RE: Absolutely nothing to do with
> > 'Small schools.& elections'
> > 
> > 
> > Is it really a turing machine if it can drive a display?
> > 
> > --
> > Joshua Boyd
> > 
> > On Wed, 20 Jun 2001, Ken Hansen wrote:
> > 
> > > Ever tried to play Doom on a Turing machine? That was rough... (but it did run Linux!)
> > 
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> 
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