Editing Calculator (section)

====Programmable pocket calculators====
The first programmable pocket calculator was the [[HP-65]], in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. Two years later the [[HP-25C]] introduced ''[[continuous memory]]'', i.e., programs and data were retained in [[CMOS]] memory during power-off. In 1979, HP released the first ''[[alphanumeric]]'', programmable, ''expandable'' calculator, the [[HP-41]]C. It could be expanded with [[random-access memory]] (RAM, for memory) and [[read-only memory]] (ROM, for software) modules, and peripherals like [[bar code]] readers, [[microcassette]] and [[floppy disk]] drives, paper-roll [[thermal printer]]s, and miscellaneous communication interfaces ([[RS-232]], [[HP-IL]], [[HP-IB]]).
[[File:HP-65 white background.jpg|thumb|left|The [[HP-65]], the first programmable pocket calculator (1974)]]
The first Soviet pocket battery-powered programmable calculator, [[Elektronika]] ''[[B3-21]]'', was developed by the end of 1976 and released at the start of 1977.<ref>{{cite web |title=Elektronika B3-21 |website=www.rskey.org |url=http://www.rskey.org/b3-21 |access-date=2023-06-07 |archive-date=2015-07-03 |archive-url=https://web.archive.org/web/20150703003847/http://www.rskey.org/b3-21 |url-status=live}}</ref> The successor of B3-21, the [[Elektronika B3-34]] wasn't backward compatible with B3-21, even if it kept the [[reverse Polish notation]] (RPN). Thus B3-34 defined a new command set, which later was used in a series of later programmable Soviet calculators. Despite very limited abilities (98 bytes of instruction memory and about 19 stack and addressable registers), people managed to write all kinds of programs for them, including [[adventure game]]s and libraries of calculus-related functions for engineers. Hundreds, perhaps thousands, of programs were written for these machines, from practical scientific and business software, which were used in real-life offices and labs, to fun games for children. The [[Elektronika MK-52]] calculator (using the extended B3-34 command set, and featuring internal [[EEPROM]] memory for storing programs and external interface for EEPROM cards and other periphery) was used in Soviet spacecraft program (for [[Soyuz TM-7]] flight) as a backup of the board computer.

This series of calculators was also noted for a large number of highly counter-intuitive mysterious undocumented features, somewhat similar to "[[synthetic programming]]" of the American [[HP-41]], which were exploited by applying normal arithmetic operations to error messages, jumping to nonexistent addresses and other methods. A number of respected monthly publications, including the popular science magazine ''[[Nauka i Zhizn]]'' (''Наука и жизнь'', ''Science and Life''), featured special columns, dedicated to optimization methods for calculator programmers and updates on undocumented features for hackers, which grew into a whole esoteric science with many branches, named "[[yeggogology]]" ("еггогология"). The error messages on those calculators appear as a Russian word "YEGGOG" ("ЕГГОГ") which, unsurprisingly, is translated to "Error".

A similar hacker culture in the US revolved around the [[HP-41]], which was also noted for a large number of undocumented features and was much more powerful than [[B3-34]].