The copy computation
Assume you have 2 identical copies of a tape
- How much energy does is take to clear them both?
- Answer: The same as clearing one tape by itself
- Clearing the first tape may cost energy
- Use the information from the first to erase the second
- The two tapes contain no more information than one
How much energy does it take to copy a tape?
- Intuitively: None (same information in one tape as two)
- How do we do it?