People seem to suggest that one needs to start a new kernel to keep multiple Mathematica (MMA) notebooks independent e.g. Kernel management link. But I did not do so and still found my two notebooks running independently.
I opened the first notebook and entered
Then, in the second notebook, I entered
and it gave me
instead of '3' thereby indicating that the two notebooks are independent. When I go to 'Evaluation >> Quit Kernel', I find only one option 'Local' in both the notebooks indicating that both notebooks are using the same kernel 'Local'.
So, how can multiple notebooks run independently despite being on the same kernel?