Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators follow their operands, in contrast to prefix or Polish notation (PN), in which operators precede their operands. The notation does not need any parentheses for as long as each operator has a fixed number of operands.
A scientific calculator is an electronic calculator, either desktop or handheld, designed to perform calculations using basic and advanced mathematical operations and functions. They have completely replaced slide rules as well as books of mathematical tables and are used in both educational and professional settings.
The HP-65 is the first magnetic card-programmable handheld calculator. Introduced by Hewlett-Packard in 1974 at an MSRP of $795, it featured nine storage registers and room for 100 keystroke instructions. It also included a magnetic card reader/writer to save and load programs. Like all Hewlett-Packard calculators of the era and most since, the HP-65 used Reverse Polish Notation (RPN) and a four-level automatic operand stack.
RPL is a handheld calculator operating system and application programming language used on Hewlett-Packard's scientific graphing RPN calculators of the HP 28, 48, 49 and 50 series, but it is also usable on non-RPN calculators, such as the 38, 39 and 40 series. Internally, it was also utilized by the 17B, 18C, 19B and 27S.
The HP 33s (F2216A) was a scientific calculator marketed by Hewlett-Packard. It was introduced in 2003 as the successor to the HP 32SII, and discontinued on the introduction of its successor the HP 35s in 2007.
The HP-41C series are programmable, expandable, continuous memory handheld RPN calculators made by Hewlett-Packard from 1979 to 1990. The original model, HP-41C, was the first of its kind to offer alphanumeric display capabilities. Later came the HP-41CV and HP-41CX, offering more memory and functionality.
The HP-20S (F1890A) is an algebraic programmable scientific calculator produced by Hewlett-Packard from 1987 to 2000.
The HP-27S was a pocket calculator produced by Hewlett-Packard, introduced in 1988, and discontinued between 1990 and 1993. It was the first HP scientific calculator to use algebraic entry instead of RPN, and though it was labelled scientific, it also included features associated with specialized business calculators.
HP calculators are various calculators manufactured by the Hewlett-Packard company over the years.
There are various ways in which calculators interpret keystrokes. These can be categorized into two main types:
The HP 9800 is a family of what were initially called programmable calculators and later desktop computers that were made by Hewlett-Packard, replacing their first HP 9100 calculator. It is also named "98 line". The 9830 and its successors were true computers in the modern sense of the term, complete with a powerful BASIC language interpreter.
The Hewlett-Packard Voyager series of calculators were introduced by Hewlett-Packard in 1981. All members of this series are programmable, use Reverse Polish Notation, and feature continuous memory. Nearly identical in appearance, each model provided different capabilities and was aimed at different user markets.
The HP-25 was a hand-held programmable scientific/engineering calculator made by Hewlett-Packard between early January 1975 and 1978. The HP-25 was introduced as a cheaper alternative to the ground-breaking HP-65.
The HP-15C is a high-end scientific programmable calculator of Hewlett-Packard's Voyager series produced between 1982 and 1989.
The HP-16C Computer Scientist is a programmable pocket calculator that was produced by Hewlett-Packard between 1982 and 1989. It was specifically designed for use by computer programmers, to assist in debugging. It is a member of the HP Voyager series of programmable calculators. It was the only programmer's calculator ever produced by HP, though many later HP calculators have incorporated most of the 16C's functions.
The HP-28C and HP-28S were two graphing calculators produced by Hewlett-Packard from 1986 to 1992. The HP-28C was the first handheld calculator capable of solving equations symbolically. They were replaced by the HP 48 series of calculators, which grew from the menu-driven RPL programming language interface first introduced in these HP-28 series.
The HP 35s (F2215A) is a Hewlett-Packard non-graphing programmable scientific calculator. Although it is a successor to the HP 33s, it was introduced to commemorate the 35th anniversary of the HP-35, Hewlett-Packard's first pocket calculator. HP also released a limited production anniversary edition with shiny black overlay and engraving "Celebrating 35 years".
The HP-55 was a programmable handheld calculator, a lower-cost alternative to the HP-65. Introduced by Hewlett-Packard in 1975, it featured twenty storage registers and room for 49 keystroke instructions. Its outward appearance was similar to the HP-65, but its silver band went through between the display and the keyboard like HP-45, and the functions of some keys were different from HP-65, and it did not have a magnetic card reader/writer. Like all Hewlett-Packard calculators of the era and most since, the HP-55 used Reverse Polish Notation (RPN) and a four-level automatic operand stack.
In computing FOCAL character set refers to a group of 8-bit single byte character sets introduced by Hewlett-Packard since 1979. It was used in several RPN calculators supporting the FOCAL programming language, like the HP-41C/CV/CX as well as the later HP-42S, which was introduced in 1988 and produced up to 1995. As such, it is also used by SwissMicros' DM41/L, both introduced in 2015, and is implicitly supported by the DM42, introduced in 2017.
The HP-30 or Spice series are RPN Scientific hand-held calculators introduced by Hewlett-Packard in 1978. Some models are programmable.
