I believe it is RPL for the HP-50.
RPN was the initial language style system for HP calculators. Stack limited to 4 levels.
RPL started with HP-28c; stack limited only by memory.
Regards,
Steve
On Mon, May 21, 2012 at 6:44 AM, willowvst <willowvst@...> wrote:
You mean RPN... I was tempted by the new HP39GII with a grey scale screen; colour screens seem to be power hungry but a grey scale screen would improve the appearance of the HP50.
It's interesting, we know HP for RPN (in calculators); but one of the strengths of the HP50 is the algebraic mode.