It is possible to have any number of Calc mode buffers at once.
Usually this is done by executing M-x another-calc, which
is similar to C-x * c except that if a *Calculator*
buffer already exists, a new, independent one with a name of the
form *Calculator*<n> is created. You can also use the
calc-mode to put any buffer into Calculator mode, but
this would ordinarily never be done.
The q (
calc-quit) command does not destroy a Calculator buffer;
it only closes its window. Use M-x kill-buffer to destroy a
Each Calculator buffer keeps its own stack, undo list, and mode settings
such as precision, angular mode, and display formats. In Emacs terms,
variables such as
calc-stack are buffer-local variables. The
global default values of these variables are used only when a new
Calculator buffer is created. The
calc-quit command saves
the stack and mode settings of the buffer being quit as the new defaults.
There is only one trail buffer, *Calc Trail*, used by all Calculator buffers.