Talk:Reversible computing

message: I'm reinforcing the point above regarding the Practical logical reversibility section, which at the very least needs an initial sentence explaining that the reversibility of an "undo" command is not the same sort of reversibility in the discipline of thermodynamics.  The main thrust of this article is entropy.  This section, however, is in no way about the limits and/or reduction of accrued entropy as it applies to computation.  Any undo function as discussed in this section increases the statistical disorder of the system by increasing W (the number of ways the bits may be arranged to achieve the energy of the system) and heat is wasted to facilitate this additional work.  Undo functions - meta or not - do nothing to mitigate entropy.  From the perspective of entropy undoing something is the same as doing something computationally. Entropy is increased similarly in either case.  I question this section's relevance to this article.Wolfworks (talk) 06:50, 15 March 2008 (UTC)
thread_title:  "Undo"?? 

message: I oppose the proposed merge.  While Landauer's principle could be a section of a general 'physics of computing' article, its importance to reversible computing doesn't really make it a subtopic any moreso than the Church-Turing thesis or the Third Law of Thermodynamics.  Discussion of the subject does take up the bulk of the article, but that really speaks more to the lack of any further useful information provided.--207.245.10.241 (talk) 00:51, 17 February 2009 (UTC)
thread_title:  Merge with Landauer's principle? 

message: I'm removing this, recently contributed by :
Logical information is stored as the physical state of the system. Changing the state of a physical system requires force, although this energy is not necessarily lost. The energy of the system can be conserved, but for non-reversible functions this energy is simply discarded by dissipating the energy into the environment. This can be easily imagined with a simple TTL "and" gate that is recieving up to two high inputs but only contributing up to one to the system. The transistors in the chip dump this energy through electrical resistance. But if this energy is not discarded, but rather captured, either in memory or by the effect of reversible logic, then the information is still available and the energy is still "in the system."
It seems to me that there are a number of problems here -- eg "Changing the state of a physical system requires force, although this energy is not necessarily lost".  Also the example of the TTL gate is misguided.  It doesn't help to think about signals; rather, what we're dealing with here is operations on memory, storing back into that memory.  And it is certainly not that "energy" from a "high input" is being dumped into the system.  Rather, it is that you have to expend energy if you want to push through an irreversible change.  So setting one bit A equal to another bit B, regardless of the previous state of B is more of a classic case.
Can I suggest that if more physical examples are desired, these be taken from reliable sources, not original research.  Jheald (talk) 09:35, 26 March 2009 (UTC)
thread_title:  Removed new paragraph 

message: ...because this is all gibberish to the layperson.  —Preceding unsigned comment added by 98.110.59.236 (talk) 04:14, 4 May 2010 (UTC)
thread_title:  Any chance we can get this article in English? 

message: Is reversible computation fundamentally different from non-reversible computation in terms of computability or complexity? E.g. are there Turing-complete versions of reversible computation?
74.125.59.1 (talk) 20:22, 1 October 2010 (UTC)
thread_title:  Turing-Complete? 

message: The section:
"For computational processes that are nondeterministic (in the sense of being probabilistic or random), the relation between old and new states is not a single-valued function, and the requirement needed to obtain physical reversibility becomes a slightly weaker condition, namely that the size of a given ensemble of possible initial computational states does not decrease, on average, as the computation proceeds forwards."
Shouldn't this conclude;
"...possible initial computational states does not increase, on average, as the computation proceeds forwards."?
User:Wozama 11:20, 9 June 2011 (UTC)
thread_title:  Reversible Computing 

message: yeah, no, somebody is riding their crackpot hobby horse here 2A01:CB0C:CD:D800:DD3A:6C0:249E:DC45 (talk) 08:37, 25 May 2023 (UTC)
thread_title:  " the second law of thermodynamics itself can be understood to be a direct logical consequence of the underlying reversibility of physics,"