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    Hacker Public Radio

    Hacker Public Radio is an podcast that releases shows every weekday Monday through Friday. Our shows are produced by the community (you) and can be on any topic that are of interest to hackers and hobbyists.

    Advertise

    Copyright: © Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) License

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    Latest Episodes:
    HPR4744: HPR Beer Garden 21 - Mild Oct 08, 2026
    Show notes

    This show has been flagged as Clean by the host.

    In this episode we look at a very old style of beer known as Mild. Paul, in the absence of any locally available Milds has a Guinness, Dave tastes Banks's Mild and Kevie Samples 1950s Burton Ruby Mild .

    Connect with the guys on Untappd :

    • Dave
    • Paul
    • Kevie

    The intro sounds for the show are used from:

    • https://freesound.org/people/mixtus/sounds/329806/
    • https://freesound.org/people/j1987/sounds/123003/
    • https://freesound.org/people/greatsoundstube/sounds/628437/

    The next 3 beer styles to be reviewed:

    • Bitter
    • Pale Ale
    • Trappist

    Provide feedback on this episode.


    HPR4743: wl-copy Oct 07, 2026
    Show notes

    This show has been flagged as Clean by the host.

    wl-copy is a command in the wl-clipboard package, and allows you to copy and paste data from your Linux Terminal on a Wayland desktop.

    Copy an arbitrary string to your clipboard using wl-copy:

    
    $ wl-copy "hello world"
    

    Paste it anywhere on your system as usual (with Ctrl+Shift+V or a right-click and Paste).

    You can copy from output, too:

    
    $ echo "hello wide world" | wl-copy
    

    You can redirect to wl-copy:

    
    $ echo "hello world" > example.txt
    
    $ wl-copy < example.txt
    

    You can use wl-paste to paste from your system clipboard:

    
    $ wl-paste
    
    "hello world"
    

    Provide feedback on this episode.


    HPR4742: OLF Call for presentations open Oct 06, 2026
    Show notes

    This show has been flagged as Clean by the host.

    OLF Conference

    The Conference the artist previously known as the Ohio Linux Festival, is returning to it's 2003 beginnings on the campus of Dreese Laboratories at Ohio State University

    Starting at noon on Friday Nov 20 and running all day Saturday 21 Nov 2026, during this event, Open Source projects, developers and visitors can exchange ideas and knowledge.

    Interviewees

    HPR is no stranger to OLF , and we interview the team as a call for presentations is now open.

    Vance has been using Linux since 1997 and was active in the Western Pennsylvania Linux Users Group from 2003 to 2017. In addition to general desktop use, he has an interest in system and network administration. Vance currently lives in Pittsburgh and works in quality assurance for safety equipment. Vance first began volunteering with Ohio LinuxFest in 2006. He worked on producing audio recordings of sessions starting in 2009, served as Speaker Chair for the 2014 through 2017 conferences, and was Birds of a Feather Chair from 2018 to 2020. He took on the Conference Chair role from 2021 through 2023, then returned as Speaker Chair starting in 2024.

    Email

    Beth Lynn currently lives in Pittsburgh and works as Senior System Engineer. She has over twenty years experience in managing, building and collaborating with teams within Free Software Expertise in GNU/Linux distributions such as Red Hat Enterprise Linux, Fedora, Ubuntu, and SUSE. From 2002 to 2011 Beth Lynn led the Western PA Linux Users Group, which began at Carnegie Mellon University.

    Beth Lynn first came to OLF as an attendee in 2003. She immediately signed up to help at future conferences. When a mix up occurred in the venue early in the OLF history, Beth contacted Jon “maddog” Hall and others for help, which saved that year’s conference (close to the date of the event). Due to her longevity with OLF over the years she has been a speaker, conference chairperson, and fundraiser. When the original conference chairpersons retired from leadership roles, Beth Lynn stepped up to keep the conference running smoothly as the Director. In 2007 Beth applied and defended 501(c)(3) non-profit status for the organization.

    Beth Lynn Eicher is passionate about the ideals of FOSS and in growing community across the country and world in this movement. She attends other Linux- FOSS conferences and is well known across the country. In 2013 she was asked to speak at the Free Software Foundation Conference held at Harvard University on the topic of “Closing the Digital Divide”. There she reported on the successful deployment of 100 Edubuntu PCs to schools in Ghana, Africa that served mostly orphaned children. Beth Lynn went to Ghana with a team from Computereach, training in networking, pc repair, the GNU/Linux command-line, and the Edubuntu desktop environment.

    Email

    Links

    • Main web site: https://olfconference.org/
    • News page (announcements): https://olfconference.org/news/
    • RSS Feed of news: https://olfconference.org/feed/
    • CFP: https://olfconference.org/call-for-presentations/
    • YouTube channel: https://www.youtube.com/@OLFConference
    • Livestream videos: https://www.youtube.com/@OLFConference/streams
    • Edited videos: https://www.youtube.com/@OLFConference/videos
    • Facebook: https://www.facebook.com/ohiolinux/
    • LinkedIn: https://www.linkedin.com/groups/1828509
    • X/Twitter: https://x.com/ohiolinux
    • Matrix (unofficial): https://matrix.to/#/#olf:matrix.org
    • Mailing list (announcements only): https://lists.ohiolinux.org/mailman/listinfo/olf-attendees
    • https://hackerpublicradio.org/correspondents/0459.html
    • https://www.osu.edu/
    • FreedomBox
    • hpr4256 :: Birds of a Feather Talk at OLF 2024

    Travel Times

    Country Typical Travel Method Example Destination Approx Duration Typical Budget Cost (One Way)
    USACarCincinnati, Ohio1h 40m–2h 10m$20–40
    USABusCincinnati, Ohio2h–3h$20–45
    USATrainCincinnati, Ohio2h–3h$25–60
    USAAeroplaneChicago, Illinois1h 10m flight$70–180
    USACarCleveland, Ohio2h–2h 45m$25–50
    USABusCleveland, Ohio2h 45m–4h$25–55
    USATrainCleveland, Ohio2h 30m–4h$25–70
    USAAeroplaneDetroit, Michigan1h flight$70–180
    USACarDayton, Ohio1h 15m–2h$15–30
    USABusDayton, Ohio1h 30m–2h 30m$15–35
    USATrainToledo, Ohio2h 30m–3h 30m$25–60
    USAAeroplanePittsburgh, Pennsylvania1h flight$70–180
    USACarPittsburgh, Pennsylvania3h–3h 30m$35–65
    USABusPittsburgh, Pennsylvania3h 30m–5h$25–60
    USATrainPittsburgh, Pennsylvania3h 30m–5h$30–70
    USACarIndianapolis, Indiana2h 45m–3h 15m$30–55
    USABusIndianapolis, Indiana3h 30m–5h$30–65
    USATrainIndianapolis, Indiana4h+$40–80
    USAAeroplaneIndianapolis, Indiana~1h flight$70–180
    USACarFort Wayne, Indiana2h 30m–3h$30–50
    USABusFort Wayne, Indiana3h 30m–5h$25–60
    USACarErie, Pennsylvania2h 30m–3h$25–50
    USABusErie, Pennsylvania3h 30m–5h$25–60
    USATrainErie, Pennsylvania3h–4h 30m$25–65
    USACarCharleston, West Virginia2h 45m–3h$30–55
    USABusCharleston, West Virginia4h–5h 30m$30–70
    USACarLouisville, Kentucky3h–3h 30m$35–60
    USABusLouisville, Kentucky4h–5h 30m$30–70
    USAAeroplaneLouisville, Kentucky~1h flight$70–180
    CanadaCarWindsor, Ontario3h–3h 30m$35–65
    CanadaBusWindsor, Ontario4h–6h$40–80
    CanadaAeroplaneToronto, Ontario~1h 15m flight$100–250

    Provide feedback on this episode.


    HPR4741: HPR Community News for September 2026 Oct 05, 2026
    Show notes

    This show has been flagged as Explicit by the host. New hosts Welcome to our new hosts: Trurl Last Month's Shows Id Day Date Title Host 4717 Tue 2026-09-01 Visit with a blind Ham operator Archer72 4718 Wed 2026-09-02 Programmable Logic Controls - Episode 2 Whiskeyjack 4719 Thu 2026-09-03 How to use a multimeter, introduction and basic usage number9 4720 Fri 2026-09-04 Robert A. Heinlein: Earlier Novels Ahuka 4721 Mon 2026-09-07 HPR Community News for August 2026 HPR Volunteers 4722 Tue 2026-09-08 Show and tell: AI tropes Trollercoaster 4723 Wed 2026-09-09 friedcamp interviews part 3: The fried telephone system Kristoff 4724 Thu 2026-09-10 HPR Beer Garden 19 - Lager Kevie 4725 Fri 2026-09-11 HPR Beer Garden - Tasting and reviewing beers Kevie 4726 Mon 2026-09-14 Trurl's intro show Trurl 4727 Tue 2026-09-15 friedcamp interviews part 4: The free Lantern Kristoff 4728 Wed 2026-09-16 Programmable Logic Controls - Episode 3 Whiskeyjack 4729 Thu 2026-09-17 Living under a rock MrX 4730 Fri 2026-09-18 Playing Civilization VI Part 1 Ahuka 4731 Mon 2026-09-21 A Website Hacked Lee 4732 Tue 2026-09-22 Webp Klaatu 4733 Wed 2026-09-23 Static Adict Episode 1: Pulse Demon TheDUDE 4734 Thu 2026-09-24 HPR Beer Garden 20 - TuxJam Half-cut Special Kevie 4735 Fri 2026-09-25 hpr4715 :: friedcamp interviews part 5: Yvon Masyn Kristoff 4736 Mon 2026-09-28 How to replace the battery in a car key fob Ken Fallon 4737 Tue 2026-09-29 Keep spare parts for Ethernet run Archer72 4738 Wed 2026-09-30 Programmable Logic Controls - Episode 4 Whiskeyjack Comments this month Past shows hpr4673 (2026-07-01) "First contact conversation" by Archer72. Dave Lee (thelovebug) said: "Baofeng naming conventions" (2026-09-16 07:07:02) hpr4677 (2026-07-07) "UNIX Curio #10 - Checksums and Hashes" by Vance. Cli said: "Systemd Topics" (2026-09-13 05:19:58) hpr4702 (2026-08-11) "MakeACopy is an open-source document scanner app for Android" by Ken Fallon. Archer72 said: "What's not to like? " (2026-09-09 21:55:48) hpr4709 (2026-08-20) "Peertube: my two penneth" by Kevie. Kevie said: "links" (2026-09-08 08:15:24) This month's shows hpr4718 (2026-09-02) "Programmable Logic Controls - Episode 2 " by Whiskeyjack. Trey said: "OpenPLC" (2026-09-02 22:40:23) Whiskeyjack said: "Reply to Trey on OpenPLC" (2026-09-03 16:05:35) hpr4719 (2026-09-03) "How to use a multimeter, introduction and basic usage" by number9. Ken Fallon said: "Thanks !" (2026-09-03 07:43:52) Archer72 said: "Thanks! Quite interesting!" (2026-09-03 09:49:32) Trey said: "Excellent episode" (2026-09-03 12:52:57) xmanmonk said: "Great show!" (2026-09-03 19:14:51) Whiskeyjack said: "Fluke Meters" (2026-09-03 22:39:30) brian-in-ohio said: "welcome" (2026-09-06 12:54:51) Kevin O'Brien said: "Endorsing comment" (2026-09-06 14:25:11) Jim DeVore said: "I learned a few things!" (2026-09-07 21:15:48) hpr4721 (2026-09-07) "HPR Community News for August 2026" by HPR Volunteers. Th3Dud3 said: "Sorry for getting your name wrong Kevie" (2026-09-09 16:27:10) hpr4722 (2026-09-08) "Show and tell: AI tropes" by Trollercoaster. Trey said: "This is so true" (2026-09-08 10:57:10) Steve Barnes said: "Re: This is so true" (2026-09-08 20:13:53) Ben said: "Great text" (2026-09-10 21:08:25) Antoine said: "AI writes very well" (2026-09-11 00:11:36) Trollercoaster said: "Re: This is so true" (2026-09-12 08:10:11) Trollercoaster said: "Re: Great Text" (2026-09-12 08:25:13) Trollercoaster said: "Re: AI writes very well" (2026-09-12 22:45:17) Antoine said: "Re #7 - Brazilian ... logic?" (2026-09-13 15:09:10) candycanearter07 said: "cool ep" (2026-09-13 20:05:22) Trollercoaster said: "Re: cool ep" (2026-09-15 17:50:02) hpr4723 (2026-09-09) "friedcamp interviews part 3: The fried telephone system" by Kristoff. Cli said: "Background noise." (2026-09-13 05:22:10) Whiskeyjack said: "Dial telephones" (2026-09-26 21:15:53) hpr4724 (2026-09-10) "HPR Beer Garden 19 - Lager" by Kevie. Gan Ainm said: "Märzen" (2026-09-14 15:32:33) Th3Dud3 said: "The reason why the USA uses Adjuncts in our Lager" (2026-09-14 18:07:03) hpr4726 (2026-09-14) "Trurl's intro show" by Trurl. candycanearter07 said: "hello!" (2026-09-15 23:22:59) hpr4732 (2026-09-22) "Webp" by Klaatu. Henrik Hemrin said: "Now I will consider webp as an alternative." (2026-09-26 17:16:21) hpr4733 (2026-09-23) "Static Adict Episode 1: Pulse Demon" by TheDUDE. brian-in-ohio said: "good show" (2026-09-23 14:44:12) Antoine said: "Never listened about" (2026-09-23 22:41:53) hpr4736 (2026-09-28) "How to replace the battery in a car key fob" by Ken Fallon. Lee said: "Replacing battery" (2026-09-29 20:24:03) Mailing List discussions Policy decisions surrounding HPR are taken by the community as a whole. This discussion takes place on the Mailing List which is open to all HPR listeners and contributors. The discussions are open and available on the HPR server under Mailman. The threaded discussions this month can be found here: https://lists.hackerpublicradio.com/pipermail/hpr/2026-September/thread.html Events Calendar With the kind permission of LWN.net we are linking to The LWN.net Community Calendar. Quoting the site: This is the LWN.net community event calendar, where we track events of interest to people using and developing Linux and free software. Clicking on individual events will take you to the appropriate web page. Provide feedback on this episode.

    Full show notes at the publisher

    HPR4740: Robert A. Heinlein in the 1960s Oct 02, 2026
    Show notes

    This show has been flagged as Clean by the host.

    The 1960s were when Heinlein produced some of his most famous works. And they started to bring him fame outside the Science Fiction community, which was most unusual.

    Heinlein in the 1960s

    Heinlein had interests that he tended to keep hidden in the early years while he was establishing himself as a writer, particularly as he was feeding the lucrative Juvenile market. These included things like sex, nudism, and unusual political and religious views. But when Scribners rejected Starship Troopers he not only abandoned writing Juveniles, but decided he could be a lot more open about his views. And this resulted in his most famous novel. This is the one novel that people who are not science fiction fans are likely to have read, particularly in the 1960s.

    Stranger In A Strange Land (1961)

    This novel won just about every award possible: Hugo, Locus, Prometheus. It was the first science fiction novel to crack the New York Times Best Seller list. And the Library of Congress named it as one of 88 “books that shaped America”. And it even introduced a new word to the English language: grok.
    The stranger in the title is Valentine Michael Smith, an infant born to one of the astronauts, and then raised by Martians. He is brought back to Earth by a later mission, and his adventures in this strange land are what the book is mostly about. But in so doing, Heinlein writes a satire on religion and also espouses very different approach to love and sexuality than was considered proper at the time. And this attracted the hippies of the 1960s, for whom it became a Bible, much to the annoyance of Heinlein who did not appreciate them knocking on his door. The book had the original title of “The Heretic”, and was intended to challenge social norms about religion and monogamy. Heinlein’s own take on the reaction to the novel was that he was surprised that some readers thought the book described how he believed society should be organized, explaining: “I was not giving answers. I was trying to shake the reader loose from some preconceptions and induce him to think for himself, along new and fresh lines. In consequence, each reader gets something different out of that book because he himself supplies the answers … It is an invitation to think – not to believe.”
    The book also exemplifies the characters that Heinlein managed to put into most of his stories. Michael is the naive young man who needs to learn better, and Jubal Harshaw is the wise old man who becomes his mentor.

    Podkayne of Mars (1963)

    The heroine of this book, Podkayne, is a teenage girl who is invited along with her younger brother on a luxury cruise with their uncle Tom from their home on Mars to go to Earth. We learn along the way that Mars was once a prison colony (echoing Australia), and that Podkayne’s family are of Maori ancestry. In the United States, at least, this would count as “colored”, and reflects Heinlein’s subversion of racist ideas in his works. Much of the travelogue on the luxury liner reflects Heinlein’s own experiences as depicted in his non-fiction book Tramp Royale which covers his own world cruise. But old uncle Tom is actually a diplomat using the kids as cover, and they get kidnapped by people who want him to take a certain position at talks to held at Luna. Podkayne’s brother Clarke is portrayed as a genius but lacking certain qualities of empathy, and in the end he manages to get her killed. The publisher rejected this ending an insisted on one where she lived. Later Heinlein published a version with both endings and invited people to vote on which one they preferred, and the one where she died won. Heinlein’s own objection was that it was like changing the ending to Romeo and Juliet into one where they both lived happily ever after. Since then the book has been published with Heinlein’s preferred ending.

    Orphans of the Sky (1963)

    This is basically a couple of novellas from 1941put together as a complete novel. The first novella, Universe, was recognized by the Science Fiction Writers of America by including it in their volume The Science Fiction Hall of Fame, Volume Two. This is a story about a generation ship, i.e. a ship that will take generations to arrive due the speed of light limit. In this case, the people who understood what this was all about are long dead, and we learn that at one point there was a mutiny and the the ship’s officers were killed. In Universe, the descendants of the remaining people think the ship is all there is, it is the Universe to them. In the second novella, Common Sense, a few people find some of the old records and work out what the situation is. Then, seeing a star growing larger ahead of them, they take a life boat and land on a habitable moon of a giant planet.
    This is part of the Future History, as Rhysling and his “Green Hills of Earth” are brought up, and it is also referred to in Time Enough For Love, where it is revealed that this ship is the sister ship to the one the Howard Families stole in Methusaleh’s Children. But being that this is from 1941 it does not show the polish and mastery of Heinlein’s other work of the 1960s.

    Glory Road (1963)

    Some stories make you wonder if they are Fantasy or if they are Science Fiction, and this is one of them. Of course, Heinlein would just call it Speculative Fiction and not worry about it. A former soldier has just been discharged from a war in Southeast Asia. The country is not mentioned, but this is 1963 and Vietnam was just bubbling up into people’s consciousness. With nothing to do, he meets up with a gorgeous woman who invites him on a quest. This takes them to other worlds and involves a certain amount of swordplay, culminating in a sword fight against Cyrano de Bergerac. The woman turns out to be the Empress of many worlds, and the quest was to retrieve the Egg of the Phoenix, a cybernetic device containing the memories and personalities of most of her predecessors, and now she has to absorb all of this, which is fine for her but leaves or hero pretty useless. Finally he goes looking for another quest.
    This is a really good novel, and was nominated for the Hugo, but it lost out to Clifford Simak’s Way Station. We should probably discuss Simak at some point, he was an important writer with a distinct style.

    Farnhams’ Freehold (1964)

    This novel attempts to be satire on race relations, but is in my view a failure. A nuclear war happens, and a group of people in a fallout shelter find that they have been transported into the future (or is it an alternative universe?). The war pretty much destroyed the societies of the northern hemisphere, leaving things open for the Africans and other southerners to become dominant. And of course the blacks enslave the whites and re-enact the worst excesses of the ante-bellum American South. When I am in the mood to go back and re-read some Heinlein, this is not one I pick.

    The Moon Is A Harsh Mistress (1966)

    This is one of Heinlein’s best novels, set on a lunar colony. The moon has been used as a penal colony, but of course most of the people there now are descendants of the people originally exiled there. The Warden runs things, but as long as the grain shipments are on schedule he doesn’t bother much with the affairs of the “Loonies”. The background here is fascinating, describing a nearly anarchic society. Men out number women two to one, leading to some interesting marriage customs, including something called “line marriage” which is a type of group marriage. The wise old man role is played by Professor Bernardo de la Paz (Prof), while the young man he mentors is Manuel O’Kelly-Davis (Mannie). Mannie is computer technician who discovers the big mainframe computer that runs everything has become sentient. And since the computer has the acronym HOLMES, he names it Mycroft Holmes (Mike), for Sherlock’s smarter brother. They all become involved in a revolution against the Earth government, which in theory is led by Prof, but in fact is led by Mike. Since he is a computer, and keeps his sentience a secret, he creates a persona of Adam Selene to be the figurehead
    I said that the background of this lunar colony is fascinating in itself, but the book is also a discourse on the nature of government, libertarianism, and what it means to be free. That was something Heinlein was prone to do, and it did not always work well. In some of his last works he tended to pontificate in a way that left the story behind, but in this novel the story is interesting all the way through. This the novel that popularized the acronym TANSTAAFL, which means There Ain’t No Such Thing As A Free Lunch, and which is the motto of the Loonies. Hazel Stone, of The Rolling Stones, appears here as a 12-year-old girl involved in the revolution, and both she and Mike also appear in later works of Heinlein. I recommend this book highly.
    This novel won the Hugo award (by the fans), was nominated for the Nebula Award (by the writers), was named one of the Top 10 novels in the Locus poll, and won the Prometheus Hall of Fame Award.

    Links

    • https://en.wikipedia.org/wiki/Stranger_in_a_Strange_Land
    • https://en.wikipedia.org/wiki/Podkayne_of_Mars
    • https://en.wikipedia.org/wiki/Orphans_of_the_Sky
    • https://en.wikipedia.org/wiki/Glory_Road
    • https://en.wikipedia.org/wiki/Farnham%27s_Freehold
    • https://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress
    • https://www.palain.com/science-fiction/the-golden-age/robert-a-heinlein/heinlein-in-the-1960s/

    Provide feedback on this episode.


    HPR4739: Happy by shower # 3 Oct 01, 2026
    Show notes

    This show has been flagged as Explicit by the host.

    We focused, until now, on things external as examples. Let’s proceed to internal. Before, I want to note that any of these is a formula. It’s not like we can repeat a past experience we ourselves or someone lived, and feel the same thing. It’s not a guarantee, and not even the idea in sharing. It’s only this: to share and to provoke reflection.

    I was abused as a child. Hard as it is, and unerasarable, also hard was to tell someone important and do not be trusted. Child abuse is associated with multiple disorders further in life. Remembering what I passed is a relief in what gives respect to where I am now. Not to authorize me to feel anger, or as a free pass to throw everything to the air without feeling guilty — that would make something, but not good after all —, but to recognize better what is real and what is important now, and that’s much more relevant, and influential to my being in the world, than that past experience.

    Coincidences sometimes make me “wow”. When I ask, and even when I don’t directly ask, specific direction in choices, or in what to trust, it’s not rare to receive something that I see as very clear. Even when it comes as a reproach, remembering me about what I should and could be doing, but am not because of many excuses, even then, I’m still impressed, and feeling loved, because someone cares specifically – about – me .

    In general, remembering something that gave me a bad taste when thinking about before, and then, as of now, feeling differently about that event, gives me a sense of maturity. Like, what a child I was to pay so much attention to this, or to that, and now those things, unimportant as they are, don’t matter any more.

    I find myself trying to remember a word, or a concept or memorized Bible verse. Sometimes I forget, and then I go to a chain of thoughts about and end up remembering, or forget about and it comes to mind minutes or hours later. Those are “aha!” moments, as discovering something, very beautiful, for the first time. Some people have a wrong notion of memory, as if it was created once and evoked latter. No, every moment one evokes a piece of information, he is reworking that piece, and every experience after the creation of the memory potentially affects that bit of information we call a part of the memory. It’s not static, it’s dynamic. And so it’s not objective, is it?

    Yeah, that’s it.

    Thank you and bye bye.

    Provide feedback on this episode.


    HPR4738: Programmable Logic Controls - Episode 4 Sep 30, 2026
    Show notes

    This show has been flagged as Clean by the host. -------------------- 01 Introduction This is the fourth episode in an 8 part series. 02 In the previous episode we looked at the Allen Bradley PLC2, one of the very early successful Programmable Logic Controllers. In this episode we will look at another early PLC, the Siemens S5 series, and use it as an example of both how PLCs became more sophisticated, as well as an example of a different approach to the overall software architecture. Again, I will only touch on this topic lightly, this is not a course on how to program PLCs. However, I will give you enough technical detail to give you are rough idea of what they were like. -------------------- 03 S5 Historical Background Siemens are the largest PLC vendor on a global basis, and have been since the early days. Their first PLC was the S3, released in 1975, two years before Allen Bradley released the PLC2. There seems to be almost no information available on the S3, so I can't say much about it. In 1978 or 1979, sources are unclear about the exact date, Siemens released the S5 series. This was a huge step forward in capability and was the foundation of their PLC product line until replaced by the S7 series in the mid 1990s. In this episode I will focus on the U series, which were an upgrade to the original S5. -------------------- 04 A Complete Family of PLCs Fully developed, the Siemens S5 series was a complete family of products covering the entire size spectrum from smallest to largest. Siemens covered the entire industrial control market, and there was almost nothing they didn't have somewhere in their catalogue. You could spend an entire career using nothing but Siemens products for everything. 05 At the lowest end were the S5-100 series, consisting of the S5-100, 102, 103, 90, and 95. These covered everything from the small "shoebox" all in one form factor to ones which overlapped the mid range in terms of capability except for their compact I/O cards which were smaller and slower than the full size models. The S5-115 formed the mid range, coming in a "full size" form factor in terms of packaging and rack size. The S5-135 and S5-155 extended the S5-115 in terms of speed and memory. 06 In this episode I will focus on the lower end S5-100 series for the sake of simplicity, and will not make any reference to any additional capabilities of the larger models. It will be much too time consuming and confusing to try to cover everything, and there wouldn't be much point to it. -------------------- 07 Data Memory Types If you recall the previous episode, the Allen Bradley PLC2 had a data table, or memory system, that was a single linear range of memory with all I/O and internal capabilities mapped into fixed numerical addresses. Allen Bradley were to abandon this approach in their later PLC5 series introduced in the mid to late 1980s, but we won't cover that here. The Siemens S5 series however took the approach of having different types of memory addresses for different purposes. I will describe those for the S5-100 series now. 08 Input and Output Addresses The standard I/O modules for these compact PLCs had 8 inputs or 8 outputs per I/O module. These module plugged into a flat bus (as opposed to an enclosed rack) with slots numbered from 0 through 31 in decimal. Each of these slots had an associated byte number, and each I/O point on the individual modules had a bit number. 09 Input and output addresses had the following format. Letter , number, decimal point, number. The letter was either I or Q. I indicated inputs. Q indicated outputs. The first number was the byte number, which corresponded to the physical I/O module slot. The second number was the bit number within the byte, starting from zero. 10 So "I2.3" indicated an input module located in the third slot (numbered from zero) and addressed the fourth input (numbered from zero) on that module. Outputs worked the same way. For example "Q 5.1" 11 Analogue modules could be located slots 0 through 7. Analogue if you recall, refers to voltages which have varying levels rather than just on or off, and can represent things like temperature. Each analogue module was assigned 8 bytes per slot, starting at address 64 and going up to 127. In practice many of these so called "analogue" modules had nothing to do with actual analogue voltages, but rather any advanced module which needed more address space was used here. Even later high density digital I/O used these addresses. 12 Each of these addresses could be addressed as bytes or words. In this case input bytes were indicated by an "IB" prefix, and input words were indicated by a "IW" prefix. Output bytes used a "QB" prefix and output words used a "QW" prefix. 13 Flags Flags are individual bits of internal memory that are used for storing intermediate logic values. These began with an "F" prefix. An S5-103 had a total of 2048, numbered from F0.0 to F255.7. 14 Counters Counters started with a "C" prefix. An S5-103 had 128 of these numbered from C0 to C127. 15 Timers Timers started with a "T" prefix. An S5-103 had 128 of these numbered from T0 to T127. 16 Data Blocks Programs needing to deal with byte and word memory could create what were known as "Data Blocks". These were blocks of PLC memory that could be created as the discretion of the programmer. An S5-103 could have a maximum of 254 data blocks numbered from DB2 to DB255. Two additional data blocks were reserved for the PLC's internal operations. Data blocks could contain up to 255 16 bit words. 17 However, the actual number and size of data blocks would in practice be limited by available memory. Even 20 kilo bytes was considered to be a large memory, and this had to be shared with the program. A data block would be "called" to make it the current data block. Then individual words would be addressed with the "DW" prefix. For example "DW5". -------------------- 18 Program Blocks If you recall with the PLC2, there was a "main" program and a series of optional numbered subroutines. In the S5, programs were split into "blocks". These were Organization Blocks Program Blocks Function Blocks Sequence Blocks An S5-103 could have up to 256 of each of these blocks. 19 Organization Blocks When the PLC started up, it would look for Organization Block 1 and begin execution there. You could consider this to be the equivalent of the "main" function in a C program. Organization blocks had an OB prefix. For example OB1. With a very simple program in a very small S5 PLC, all of the program logic could be simply put in OB1. However, with larger programs , it was convention to put the logic in subroutines and simply have OB1 call each subroutine. 20 Program Blocks These had a PB prefix. For example PB10. Normal ladder logic style programming would go in these. It was convention to split up a program into pieces and put piece in its own program block. Normal practice was to have a program block correspond to a particular part of the machine. 21 Function Blocks These had an FB prefix. For example FB64. Function blocks differed from program blocks in that they could take parameters. This allowed you to write an FB that performed some sort of complex data transforms and re-use it by calling it with different parameters. Some instructions could only be used in FBs, not in other types of blocks. There were also built in FBs in some CPU models which performed certain operations such as converting BCD (or Binary Coded Decimal) to normal integer. 22 Sequence Blocks These has an SB prefix. For example, SB25. These were like PBs, but were intended for controlling sequences of operations where each SB performed as single step of the sequence and multiple blocks were used for a sequence. -------------------- 23 Programming Languages The S5 series offered four different programming languages. These were Ladder (abbreviated as LAD) Statement List (abbreviated as STL) Control System Flowchart (abbreviated as SCF) GRAPH 5 24 You should be familiar with ladder if you listened to previous episodes. Briefly however, it is a graphical programming language which followed the appearance of electrical ladder wiring diagrams which were familiar to engineers, technicians and electricians working with manufacturing equipment. 25 Statement List is a text based programming language which resembles an assembly language for an abstract processor architecture. Boolean logic results were calculated and saved on a stack, while integer values were operated on directly from memory or in two accumulators, ACCU1 and ACCU 2. 26 Control System Flowchart is a graphical language that takes the form of rectangular blocks with one or more inputs and an output. These blocks are laid out on a screen and then wired together rather like logic gates in a electronic schematic. 27 GRAPH 5 is Siemens' implementation of the GRAFCET (Graphe Fonctionnel de Commande Étapes Transitions) IEC 60848 flow chart standard. The IEC are the International Electrotechnical Commission, an international standards organization. 28 I will focus on Ladder and Statement List, as these were by far the most commonly used and we have limited time to discuss the S5. -------------------- 29 Statement List As mentioned above, Statement List can be thought of as the assembly language for an abstract CPU architecture. The firmware in the S5 PLC will run the instructions in an interpreter. 30 The RLO Boolean or bit oriented instructions operate on a logic stack known as the RLO, or Result of Logic Operation. Boolean operations typically take one operand. When a boolean operation is executed, if the RLO is empty it simply loads the operand onto the RLO. If the RLO is not empty, then the instruction is executed using the operand and the RLO, and the result replaces the value on the top of the RLO stack. Some boolean instructions do not take an operand, but rather work on the two topmost values on the RLO. If you are familiar with languages such as FORTH, this should sound very familiar. 31 The Accumulators Word oriented instructions work on two accumulators, ACCU 1 and ACCU 2. A load instruction will load a word or byte value from a memory location or a constant into ACCU 1. The value that was in ACCU 1 then gets shifted into ACCU 2. A transfer instruction will write the value in ACCU 1 to memory. The remaining word oriented instructions will operate on the values in ACCU 1 and ACCU 2, and place their result in ACCU 1, overwriting the existing contents. So for example, an add instruction will add the value in ACCU 2 to the value in ACCU 1, leaving the sum in ACCU 1. 32 Ladder As mentioned above, ladder is a graphical programming language which has the appearance of an electrical control ladder diagram as used with actual relays. The is by far the most common programming language used with PLCs. A ladder program however is just another way of presenting statement list. 33 To put it another way, a statement list program can be displayed on a computer screen as either lines of text, or a graphical symbols laid out in a meaningful pattern. All valid ladder programs can be represented as statement list. However, not all valid statement list sequences can be represented as ladder. Statement list is inherently more flexible than ladder, which means that you simply can't always translate both ways fully. 34 None the less, most typical control logic can be represented as ladder, and ladder is the preferred representation as it is quicker to understand at a glance when debugging a software or hardware problem. On the other hand, some statement list instructions have no ladder equivalent, or the algorithm may not lend itself to being represented in ladder. In these cases normal practice is to put the simple control logic in ladder in Program Blocks, and put the non-translatable statement list logic in Function Blocks. 35 Control System Flowchart and GRAPH 5 Like ladder, CSF and GRAPH 5 are actually implemented in statement list, and many of the considerations mentioned above apply to those as well. However, I won't go into any further detail on these here. -------------------- 36 Programming Software and Hardware There were two ways of entering a program into an S5 PLC. One way was the hand held programming terminal. The other was via the STEP 5 programming software. 37 Hand Held Terminal Like many if not most PLC vendors, Siemens sold a hand held programming terminal. There were a series of these, an example being the PG 605. This was a box like a large calculator which had buttons and a small display. The buttons corresponded to various instructions and a numeric keypad, and the display would show the current instruction being entered. To use it you would plug a cable attached to the hand held terminal into the programming port on the front of the PLC CPU module. You could then enter or view the program, one instruction at a time. 38 STEP 5 Programming Software The other way of programming was to use software running on a PC. Siemens called their software STEP 5. This was an integrated editing and debugging program. Originally it ran on CP/M. 39 Siemens sold their own portable PCs with the software preloaded, and with additional built in hardware features such as an EPROM burner. These computers were also known as "PGs". STEP 5 was later ported to MS-DOS by running it on a CP/M emulator which people would use to run it on an off the shelf PC such as a laptop. Later still a native MS-DOS port was produced. 40 This had modes for Statement List. Ladder, and Control System Flowchart. GRAPH 5 was a separate program. You could toggle between STL, LAD, and CSF modes, and if the software could translate what was there form one mode to another, it would. 41 The PC would be connected to the PLC by a cable which had an interface box in the middle. This could be used to download a program to the PLC, upload a program to take a backup, modify a running program, or debug a running program. -------------------- 42 Instructions I won't list all the instructions, as that would take too long. I will instead give a brief overview of them. I will deliberately skip over obscure instructions that would take too long to explain. 43 Basic Operations Boolean Operations There is a full set of boolean operations including and, and not, or, or not, set, reset, and assign. The assign operation would assign the RLO value to the address of the specified operand. 44 Load and Transfer The Load instruction would load the value of a memory address word or byte or a constant into accumulator 1. There are about 2 dozen variations on the load instruction. The transfer operation would write a word or byte from accumulator 1 into memory. There are about a dozen variations of the transfer operation. 45 Timers and Counters There are 5 different types of timers. Timers take the value in accumulator 1 as their preset when started. There are up counters and down counters, which count up and down respectively. Again, these take the value in accumulator 1 as the preset. 46 Arithmetic Operations The only native arithmetic operations in the S5-100U series are addition and subtraction. These add or subtract the values in accumulator 1 and 2. Another set of add instructions allows adding a constant. However, the 103 and 95 CPUs offered integer multiple and divide as integrated function blocks, FB242 and FB243. You would call these function blocks with the desired parameters and they would return their results in other parameters. 47 Comparison Operations There are a complete set of integer comparison operations which operate on the values in the two accumulators. These include greater than, greater than or equal to, etc. The boolean result is saved on the RLO. 48…

    Full show notes at the publisher

    HPR4737: Keep spare parts for Ethernet run Sep 29, 2026
    Show notes

    This show has been flagged as Clean by the host.

    Quick show on what I used to run 25 feet of Ethernet cable

    Amazon

    Cable Matters 10Gbps Snagless Cat 6 Ethernet

    Cable, 25ft, Blue 24 AWG Bare Copper, Gold-Plated

    RJ45, PoE++, 550MHz

    Other supplies

    • 1/2 inch length of blue pex tubing from local hardware store

    • Leftover from previous project

    • Electrical tape

    • Extendable pole which has a clamp and a trigger mechanism for use with wasp spray

    • Hyper Tough 3/4 inch Hex Shank Spade Drill Bit

    • Random Hyper Tough (maybe 3/8 inch) drill bit All purpose

    • White silicone sealant

    Reference

    hpr4654 :: What's in my component Box?

    Images

    First part of cable run, internet router side.

    Ethernet cable, with electrical tape to pex pipe.

    Extension pole with pex pipe attached by electrical tape.

    Angle cut on pex pipe.

    Taped pex pipe with cable, ready to feed to other side.

    Extension to other side of the mobile home.

    Success! Fed through the other side.

    8 foot extension, suitable to hang an antenna.

    Silicone to seal the holes.

    Provide feedback on this episode.


    HPR4736: How to replace the battery in a car key fob Sep 28, 2026
    Show notes

    This show has been flagged as Clean by the host.

    Replacing battery

    Remove the emergency key

    Pry open the fob around the seam with a blunt knife or similar

    Note the polarity of the battery, ie which way up the battery is.

    Replace the battery and close.

    Emergency usage

    Use the emergency key to enter the car.

    Hold the key fob to the Start/Stop button

    Press the Start/Stop button

    Links

    • https://en.wikipedia.org/wiki/Nissan_Micra#Fifth_generation_(K14;_2016)
    • https://en.wikipedia.org/wiki/Button_cell
    • https://en.wikipedia.org/wiki/Near-field_communication
    • https://www.youtube.com/watch?v=IBP5EEm1oSI

    Provide feedback on this episode.


    HPR4735: hpr4715 :: friedcamp interviews part 5: Yvon Masyn Sep 25, 2026
    Show notes

    This show has been flagged as Clean by the host.

    https://www.instructables.com/member/masynmachien/

    https://www.masynmachien.be/

    https://www.instagram.com/masynmachien/

    Provide feedback on this episode.


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