[Right Wing Professor]

A calculator doesn't write back to the same tape that it read from, either, but it still performs calculations and computations, and can (for most of them) still qualify as a Turing Machine.

Sure it does. The 'tape' in a calculator includes the 32 or whatever bits in the microprocessor register, which it certainly reads from and then writes to.

[Southack]

"The 'tape' in a calculator includes the 32 or whatever bits in the microprocessor register, which it certainly reads from and then writes to."

Of course. Who knows, perhaps there is an old mechanical calulator that takes input from punched tape and writes output to a different tape.

But back to the bigger picture,

You seem to be arguing that a Turing Machine MUST write back to the identical tape that it read from.

In contrast, I am saying that writing output to ANY tape, even a different one, is still an acceptable Turing Machine.