The Museum of HP Calculators
The HP-17B was a pocket business calculator with algebraic logic. This model had an unusually sparse looking keyboard with a single shift key and shifted functions on only about 40% of its keys. Most of its functions were in menus. It had a two-line dot matrix screen like the HP-27S but it always showed a menu on the bottom line. (Usually the main menu with its FINancial, BUSiness, SUM, TIME and SOLVE submenus.)
The calculator used a form of algebraic logic with parentheses (but no precedence) in which pending operations were left in the display. For example if the user pressed "1+(2×3", the calculator would show that expression in display. On pressing ")", the calculator would evaluate the part in the parentheses and display 1+6. Like the majority of algebraic calculators, however, most unary functions were postfix (RPN) so you still typed 5 LOG not LOG(5).
Even though it was algebraic, it also had a four-level stack with roll up and roll down commands (▲ and ▼). This was called the "history stack" and the equivalent of X on an RPN model was called the "calculator line". The number on the level above could be retrieved into the current expression on the calculator line with the LAST key.
Other features included: