"All Hewlett-Packard pocket calculators feature RPN logic- the most sensible logic system a pocket calculator can have!"
Illustration of HP's four-level stack system.
"If you will look at the keyboard of any HP calculator shown in this catalog, you will see that none has an "=" key. Nor are there any keys for parentheses. None are needed.
Instead, all HP calculators have a key like this: ENTER. Thanks to this key, and RPN logic, you get four major advantages you don't get with most other calculators."
Short explanation of RPN by HP, 1975.
"All Hewlett-Packard pocket calculators feature RPN logic- the most sensible logic system a pocket calculator can have!"
This beautiful short introduction to #RPN (Reverse Polish Notation) is from Hewlett-Packard's Pocket Calculator Buyer's Guide printed in 1975.
18.01.2026 17:38 β π 6 π 1 π¬ 0 π 0
photo of the R47 calculator IRL
R47 officially goes on sale, early bird discount available here: https://47calc.com/ #calculators @calculators #rpn #hp
07.11.2025 00:14 β π 9 π 2 π¬ 0 π 0
SwissMicros Model R47 RPN Calculator
www.swissmicros.com/product/mode...
#SwissMicros' R47 is a new RPN-based programmable scientific calculator.
Its software has been refined over many years, born from the vision of a dream calculator developed by a team of engineers and mathematicians, all dedicated #RPN enthusiasts.
18.01.2026 11:48 β π 6 π 0 π¬ 0 π 0
On January 4, 1972, Hewlett-Packard introduced the HP-35, the world's first scientific handheld calculator, revolutionizing computation with its Reverse Polish Notation and key functions like trig and logs. A milestone in portable computing!
04.01.2026 07:30 β π 3 π 1 π¬ 0 π 0
HP-41C calculator from 1979
01.01.2026 22:26 β π 280 π 56 π¬ 6 π 3
MINUTEMAN * 6X, an RPN calculator introduced by Commodore in 1974.
Display of the MINUTEMAN * 6X, an RPN calculator introduced by Commodore in 1974.
Back of the MINUTEMAN * 6X, an RPN calculator introduced by Commodore in 1974.
The MINUTEMAN * 6X was an early calculator by #Commodore from 1974, the company that was later famous for legendary computers like the Commodore 64 and the #Amiga family. The #MINUTEMAN supported #RPN (reverse Polish notation), had a 2-level stack and arithmetics for integers and currency values.
18.01.2026 09:57 β π 7 π 0 π¬ 0 π 0
It may come... Plans are, in fact, maturing...
11.01.2026 17:29 β π 3 π 0 π¬ 0 π 0
Picture of the illuminated Niagara Falls at night. Seen are the Niagara River in the front, the falls in the center, and the city in the background.
The nightly illumination of the Niagara Falls is controlled by software written in #Object_Pascal with #Embarcadero #Delphi.
#Pascal_programming
marvel-b1-cdn.bc0a.com/f00000000142...
delphi.org/2017/04/the-...
www.niagaraparks.com/events/event...
28.12.2025 16:48 β π 6 π 1 π¬ 0 π 0
Like all TRURL apps, TRURL B supports and is based on #RPN, i.e., Reverse Polish Notation.
16.11.2025 17:16 β π 3 π 0 π¬ 0 π 0
Screenshot of TRURL B on macOS Ventura 13.7.8
Screenshot of TRURL B on macOS Ventura 13.7.8
A new #TRURL app has been released. TRURL B follows the design of the famous calculators created by Dietrich Lubs and Dieter Rams for the German company Braun.
It implements all fundamental operations plus power, square, square root, and the inverse operation.
sourceforge.net/projects/tru...
21.10.2025 14:04 β π 8 π 1 π¬ 1 π 1
Screenshot of the Lazarus IDE with TRURL's RPN engine and a test app using this library and FPCUnit.
The RPN engine of the #TRURL project has been released in version 1.2 (Gimel). This new version introduces a square function for your calculator apps.
#RPN #Reverse_Polish_Notation #Pascal programming.
trurl.sourceforge.io
doi.org/10.5281/zeno...
doi.org/10.5281/zeno...
21.10.2025 08:19 β π 8 π 0 π¬ 1 π 1
Screenshot for a test app of Segmitator 1.2. It shows how the input number 4.2E-6 is displayed (as 42E-7) in both text mode and as a graphic representation.
TRURL's #Segmitator 1.2 has been released. The new version includes support for high-res displays, setting the size of the decimal separator, and output of limited length.
#TRURL
trurl.sourceforge.io
21.10.2025 07:54 β π 7 π 0 π¬ 0 π 1
The Apple Pascal Poster. This poster depicts graphically the Syntax of the Pascal programming language. Coloured line graphic on a black background.
Apple's legendary #Pascal syntax poster from 1979. It was created by Jef Raskin to adapt the syntax of Bill Atkinsonβs #Apple_Pascal compiler. The poster was over the desk of every programmer at #Apple and over the desks of many programmers outside of Apple.
vintagecomputer.ca/the-history-...
19.10.2025 13:39 β π 21 π 8 π¬ 2 π 0
Banner image of the 2025 Pascal Conference with portraits of the invited keynote speakers.
Announcing the 2025 Pascal Conference
in Sundern, Germany, 18-21 September
pascalconference.com
30.08.2025 18:35 β π 11 π 5 π¬ 1 π 0
Screenshot of Lazarus 4.0 on macOS 13.7.5 Ventura.
The Lazarus IDE for Free Pascal has been launched in version 4.0. This major new release introduces multiple novel features, including new event types, extended support for Cocoa, optional docking, more debugger options and extended components.
#Lazarus_IDE #FreePascal
www.lazarus-ide.org
08.05.2025 23:47 β π 12 π 2 π¬ 0 π 0
Screenshot of the source code of TRURL's segmitator 1.1.0 with a demo app
Version 1.1.0 of TRURL's segmitator has been released. It features support for exponential notation, error messages and improved handling of small numbers.
trurl.sourceforge.io
github.com/jwdietrich21...
codeberg.org/jwdietrich/t...
19.04.2025 13:54 β π 3 π 1 π¬ 0 π 0
Screenshot of the source code of TRURL's RPN Engine 1.1.0
Version 1.1.0 of TRURL's RPN engine is available. This version introduces optional HP-like behaviour to the roll-down function of the stack.
trurl.sourceforge.io
github.com/jwdietrich21...
codeberg.org/jwdietrich/t...
doi.org/10.5281/zeno...
19.04.2025 13:51 β π 3 π 1 π¬ 0 π 0
Screenshot of TRURL G 1.2.1 on macOS 13.7
#TRURL G has been updated to version 1.2.1. This is a recommended bug-fix release that addresses an issue with the erroneous display of small numbers and makes the roll-down feature more HP-like.
TRURL is available from trurl.sf.net.
16.04.2025 20:03 β π 2 π 2 π¬ 0 π 0
Screenshot of MacPaint 1.5 (1985)
MacPaint screenshot with Japanese Lady (1984)
Source code of the HVContrain procedure:
PROCEDURE HVConstrain(VAR newPt: Point);
VAR dh,dv: INTEGER;
BEGIN
IF shiftFlag THEN { constrain to horiz or vert }
BEGIN
IF hConstrain AND vConstrain THEN { still chosing direction }
BEGIN
dh := ABS(newPt.h-ptConstrain.h);
dv := ABS(newPt.v-ptConstrain.v);
IF (dh > dv) AND (dh > 1) THEN vConstrain := FALSE;
IF (dv > dh) AND (dv > 1) THEN hConstrain := FALSE;
END;
IF hConstrain THEN newPt.v := ptConstrain.v; { horiz }
IF vConstrain THEN newPt.h := ptConstrain.h; { vert }
END;
END;
MacPaint was a revolutionary app that demonstrated the capabilities of early #Macintosh computers. Jeffrey Starr reviews its source code in his blog. The code in #Pascal and assembly language, while still in old procedural style, is an example of good programming practice.
ztoz.blog/posts/macpai...
06.04.2025 21:10 β π 7 π 2 π¬ 1 π 0
Screenshot of TRURL G 1.2 on macOS 13.7.4 Ventura
Screenshot of TRURL G 1.2 on macOS 13.7.4 Ventura, showing an error message.
#TRURL G 1.2.0 (Columbia) has been released. This new version introduces extended error-handling capabilities.
trurl.sf.net
23.02.2025 09:14 β π 7 π 1 π¬ 0 π 0
Screenshot of a test app for segmitator. It shows two virtual seven-segment displays implemented with different techniques (ASCII and graphics)
Screenshot of parts of Segmitator`s sourcecode in Object Pascal.
#TRURLββs #Segmitator library has been updated to version 1.0.1, implementing a bug fix.
trurl.sf.net
23.02.2025 08:52 β π 7 π 1 π¬ 0 π 0
Get my art book 'Worlds Beyond Time!' https://linktr.ee/70sscifiart
Publishers Weekly says my "obvious love for the form animates the volume." And I'll animate again! I'll never stop animating volumes
Chief Curiosity Counselor
Retro tech, early web & vintage computing. 80s, 90s, 2000s nostalgia. Follow for daily posts.
Childless Cat Man Pro Science Pro Choice Pro Democracy Reject Project 2025 I pay for good journalism and give it away. Merchant of love oil. Hapless actor. Be of good cheer! The North will rise again!! https://www.sexualecstasy.org/?cp
Data Scientist by day. Geek by night. π€
Co-Founder of MakerSpace Bonn & OKLab Bonn.
"Du bist das Ergebnis 3,8 Milliarden Jahre evolutionΓ€ren Erfolges. Benimm Dich gefΓ€lligst auch so." (Urheber unbekannt) | WG-Chefin von #zweikΓ€tzkes
Physiker, Autor, WissenschaftserklΓ€rer, Kolumnist. Wien, Europa, MilchstraΓe & Umgebung. Glaube nicht alles, was du denkst!
https://ko-fi.com/florianaigner
museum geek, cs, father, husband, ally, believer in equity, guitarist, photography, philosophy, art, lover of love - i don't like bigots. tell me how i can help. he/him
Amateur astronomer - Astronomy for Everyone show since 2009 https://www.youtube.com/c/astronomyforeveryone
Writing a book. Have dogs.
Tell jokes - I used to tell dad jokes. Sometimes he'd laugh.
Something with computers for a living.
I don't really do DMs.
Social Justice Bard. They/them. Gay; tired.
Renee Nicole Good was murdered by ICE and ICE has not faced justice.
4-level Reverse Polish Notation
4-bit microprocessor "Nut" 1LF5-0003 ca. 400kHz
319+124 Registers
12 alphanumeric LCD
4 input/output ports
FOCAL programmings
Bad at writing profiles. Cat dad to Gnocchi and (Potato) Latke (they are in my profile picture, behind and under a couch, no way to add alt text)
He/him.
Feminist rabbi. I like democracy and inclusive education. #ParshaChat
βοΈSammlerin der Sonnenstrahlen im Leben βοΈ
Patientensprecherin #Twankenhaus
#EhlersDanlosSyndrome #hEDS #SFN #MCAS
#kptbs #dis #DissoziativeIdentitΓ€tsstΓΆrung #Trauma #NotJustSad, #ADHS, v.A. #Autismus
#rareDisease #SelteneErkrankung
#Assistenzhund
Who knows me better suggests that integrity, intellectual curiosity, analytical depth, pragmatism, and vision are my defining characteristics.
Socratic reasoning compels me to challenge assumptions, and uncover the deeper truths that shape our world.
π©πΉπ₯°βοΈSciCommπ³οΈβπ
β’ Postgrad Archaeology StudentπΊ(Portrayal of the past in media)
β’ Computer Scientist π©βπ»
β’ Lesbian Poetess π
β’ Novelist - prehistory/antiquity
β’ EDXRF/Gamma/Xray Spectroscopy β’οΈ
β’ Astrophotographyπ
β’ ASD/ADHD/Tourette's/CPTSDπ΅βπ«
β’ Weaverπ§΅
