RCLcalculators
RCL, a simulator for Texas Instrument calculators from the 70's.
... specific: TI calculators) an option to have your old calculator under your control again.
Looking for user manuals? go to http://www.rskey.org/CMS/index.php/the-library/12 (The site owner does a great job at preserving the history and the documentation of calculators of the period.)
RCL is targetting developers interested in applying the Von Neumann architecture and attributed grammars and developers with a need to do complex calculations in their applciacation.