Hacker Public Radio

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.

Episodes

  1. 3d ago

    HPR4722: Show and tell: AI tropes

    This show has been flagged as Explicit by the host. Obviously, I'll need to introduce why I'm the best person to explain this concept and how I did my research. After that, I dive into the core of he episode: the research. The Ultimate Guide To Spotting AI Generated Text That Every Writer Needs To Read. That title already has two tells: Title case : every word capitalised, which conveniently cannot be read out loud Hyperbole : a promise of ultimacy, for a ten minute podcast For most of this episode I am not myself, I am the machine, and every sentence I say is an example of the thing it describes. This page is the key to that part of the show: the tells in the order you hear them, with what they sound like in the recording. Most names come from tropes.fyi , so you can look them up there and get the longer explanation. As also stated in the podcast: these aren't errors. They are ordinary figures of speech that human writers have used for centuries. The tell is the density. Part one: Vocabulary Prestige vocabulary : words nobody uses out loud. e.g. delve, harness, utilise, robust, foster Grand nouns for ordinary things : e.g. tapestry, landscape, realm, ecosystem, paradigm Magic adverbs : imply significance, carry no information. e.g. quietly, fundamentally, arguably, remarkably Avoiding the verb "to be" : plain "is" swapped for something that sounds busier. e.g. serves as, stands as, represents, marks Invented concept labels : an abstract problem noun (trap, creep, paradox, inversion) welded onto a domain word, then used as if it were established. e.g. "the fluency trap", "prestige creep" Vague attributions : authority without a name. e.g. "experts agree", "industry reports suggest", "observers have noted" Appeal to familiarity : consensus claimed rather than proven. e.g. "a classic", "famously", "as we all know" Promotional register : describing turns into selling. e.g. unlocks, seamless, unprecedented Part two: Sentence shapes Negative parallelism : the "it's not X, it's Y" pattern, and the most reported tell of all. e.g. "This isn't a stylistic quirk, it's a structural signature." Not X. Not Y. Just Z. : the same move tripled, building tension for a reveal that needed none. e.g. "Not a habit. Not a tic. A tell." Sets of three : one tricolon is elegant, three in a row is a stuck needle. e.g. "it arrives in threes, it lands in threes, it exhausts in threes" Short punchy fragments : emphasis manufactured by full stops instead of earned by content. e.g. "Short. Parallel. Relentless." Self-answered questions : asks what nobody asked, answers it immediately. e.g. "The problem? Nobody asked." Anaphora : the same sentence opening until it becomes furniture. e.g. "They open sentences the same way. They open the next one the same way." Trailing "-ing" analysis : shallow significance bolted onto a finished sentence. e.g. "highlighting its enduring importance", "reflecting broader trends" False ranges : "from X to Y" where there is no scale and no middle. e.g. "from cesspit to citation" Filler transitions : connect nothing to nothing. e.g. "it's worth noting", "importantly", "notably" The interjection reflex : every sentence broken in half, whatever the punctuation. e.g. em-dash, double hyphen, comma pair, colon Comma-clipped tail : a short phrase hung off a comma instead of landing the point. e.g. "above the content, and save." Part three: Tone Manufactured suspense : the buildup arrives, the revelation does not. e.g. "here's the thing", "here's the kicker" Patronising analogy : teacher mode, uninvited. e.g. "think of it as a Swiss Army knife for condescension" Forced figurative language : a metaphor picked for cleverness rather than clarity. e.g. "Picture a bicycle. Now picture that the bicycle is prose." Stakes inflation : everything is historic. e.g. "a pivotal moment in the evolution of reading itself" False vulnerability : honesty performed, never risked. e.g. "let me be honest with you here. Genuinely honest." Assertion in place of evidence : e.g. "history is unambiguous on this point", "the evidence is clear" "Imagine a world where..." : the futurism sales pitch, pleasant outcomes if you accept the premise. e.g. "imagine a world where every paragraph carries a quiet intelligence" Quotable one-liners : slide bait that survives being pulled out of context because it never had any. e.g. "Every bite is a chance to be here, now, fully." The collaborative "we" : one author, plural pronoun. e.g. "we will unpack each one in turn" Sycophancy : not a figure of speech but a training artefact, and the fastest way to spot raw chatbot output. e.g. "What a genuinely profound question." Part four: Formatting Title case headings : see the top of this page Bullet lists where prose would do : the document turns into a slide deck. e.g. this page, from here to the bottom Bold-first bullets : every item opens with a bolded keyword and a colon. e.g. yes, also this page, I know Emoji as punctuation : rocket for aspiration, key for insight, sparkles because the paragraph ended Em-dashes : mid-sentence, twice, sometimes three times, where a comma would have done the job The find and replace tell : double hyphens everywhere, because someone removed the character and kept the habit Unicode decoration : arrows and curly quotes nobody typed on a keyboard. e.g. Input → Processing → Output One thought per line : paragraphs abolished. e.g. "It happened. Alone. On a Tuesday." Part five: Composition Announce then answer : says what the text is about to do instead of doing it. e.g. "This guide will explore what those signs look like." Rapid-fire historical analogies : authority borrowed from a list, with no argument underneath. e.g. "Marconi. Sony. Apple. Print, radio, web, mobile." The metaphor that will not end : e.g. the garden that stays a garden for six sentences, then becomes a north star that moves the needle Self-echo : a word from earlier returning as if it were being paid off, when it is the same narrow vocabulary surfacing again One point diluted : the same idea in five coats, sounding like progress. e.g. "put differently", "to rephrase", "in other words" Fractal summaries : every section summarises itself, including the one you are inside. e.g. "In this section we explored composition." The tie-back : closes by looping the answer back to the original question, long after the point was made. e.g. "So, to answer your question..." Concede and dismiss : e.g. "despite its fluency, it faces challenges typical of automated systems. Despite those challenges, it endures." Signposted conclusion : competent writing does not need to announce that it is ending. e.g. "in conclusion", "to sum up", "in summary" The conclusion that refuses to end : clause stacked on clause, quieter and more meaningful each time. e.g. "the real AI generated text was the paragraphs we scrolled past along the way" Engagement bait : e.g. "Agree?" plus a pointing emoji Tells on the list that did not fit in the episode The recording would have run to forty minutes. These are worth knowing anyway. Reasoning leak : the text narrating its own decisions instead of just making them. e.g. "I want to be exact about my own role here." Premise stacking : a paragraph of evidence in front of the point, so the point has been made twice before it arrives Compulsive counting : states the number of items before listing them. e.g. "Five things we wish to discuss" Excessive enumeration : a listicle disguised as prose. e.g. "The first wall is... The second wall is..." Belaboring the unnecessary : defending a minor point against an objection nobody was going to raise Synonym cycling : refusing to repeat a noun. e.g. the dashboard, then the interface, then the portal, then the analytics hub Wh-headings : the default shape a model reaches for when naming a section. e.g. "What this means", "Why it matters" Content duplication : the same paragraph appearing twice, because the model lost track of what it had written Why this is not a detector guide Liang, Yuksekgonul, Mao, Wu and Zou, Stanford, published in Patterns (Cell Press) on 10 July 2023. Seven commercial GPT detectors were run over 91 TOEFL essays written by non-native English speakers and 88 US eighth grade essays. Average false positive rate on the TOEFL essays: 61.3 percent. 89 of the 91 essays were flagged as AI generated by at least one detector. All seven agreed on 18 of them. The US eighth grade essays came back near perfect. Plainer word choice, lower perplexity, reads as machine to the software. Feeding the TOEFL essays through ChatGPT with the prompt "enhance the word choices to sound more like that of a native speaker" dropped the false positive rate to 11.6 percent. So the way to stop being accused of writing like a machine was to have a machine rewrite you. Do not take my word for it, the paper is open access: https://www.cell.com/patterns/fulltext/S2666-3899(23)00130-7 Preprint: https://arxiv.org/abs/2304.02819 The pointers, for real Write with things in it: names, dates, prices, the model number of the drive that died. Say something a machine has no way to know, because it happened to you. Be willing to be wrong out loud. Keep one weird sentence that your editor would cut. Links and references The list this episode leaned on: tropes.fyi , by ossama.is The detector study: Liang et al., "GPT detectors are biased against non-native English writers", Patterns, 2023 "Not an Addict", K's Choice, 1995. It's not a habit, it's cool, I feel alive. "Friends, Romans, countrymen" and "I come to bury Caesar, not

  2. 4d ago

    HPR4721: HPR Community News for August 2026

    This show has been flagged as Explicit by the host. New hosts Welcome to our new hosts: Kristoff number9 Last Month's Shows Id Day Date Title Host 4696 Mon 2026-08-03 HPR Community News for July 2026 HPR Volunteers 4697 Tue 2026-08-04 Correcting the Dates of Files Vance 4698 Wed 2026-08-05 ID3 Tags and Vorbis Comments Whiskeyjack 4699 Thu 2026-08-06 Sunshine, Moonlight, Playnite !? operat0r 4700 Fri 2026-08-07 Robert A. Heinlein: The Juveniles Ahuka 4701 Mon 2026-08-10 Elsbeth muses with Lee on her experiences and opinions on AI Elsbeth 4702 Tue 2026-08-11 MakeACopy is an open-source document scanner app for Android Ken Fallon 4703 Wed 2026-08-12 Ebooks and Audiobooks Ahuka 4704 Thu 2026-08-13 HPR Beer Garden 17 - Double DDH IPAs Kevie 4705 Fri 2026-08-14 Free Software Is Wasted On You Teens Trollercoaster 4706 Mon 2026-08-17 Quirks and Customisations Lee 4707 Tue 2026-08-18 UNIX Curio #12 - expr Vance 4708 Wed 2026-08-19 Programmable Logic Controls - Episode 1 Whiskeyjack 4709 Thu 2026-08-20 Peertube: my two penneth Kevie 4710 Fri 2026-08-21 Civilization VI Ahuka 4711 Mon 2026-08-24 Second-Hand Phone TrumpetJohn 4712 Tue 2026-08-25 friedcamp interviews part 1: Wim van Gool Kristoff 4713 Wed 2026-08-26 July2026 Community News response, and Future Plans TheDUDE 4714 Thu 2026-08-27 HPR Beer Garden 18 - Amber Ale Kevie 4715 Fri 2026-08-28 friedcamp interviews part 2: Thomas Farstrike Kristoff 4716 Mon 2026-08-31 PocketMod TrumpetJohn Comments this month Past shows hpr3708 (2022-10-19) "Insomnia as a Hobby" by TrumpetJohn. Robert St.Preux said: "Insomnia as a hobby" (2026-08-30 00:56:59) hpr3766 (2023-01-09) "ACER Nitro 5 laptop review" by Bookewyrmm. wevaba6950 said: "A refreshing contrast between enterprise gear and low-power hardware" (2026-08-10 09:19:47) candycanearter07 said: "re: a refreshing contrast..." (2026-08-12 02:54:05) hpr4581 (2026-02-23) "Sharp Intake of Breath City (A.K.A.) How I learnt to stop worrying about the fork bomb" by not_toby. Windigo said: "Fantastic episode" (2026-08-08 16:51:00) hpr4655 (2026-06-05) "Tips for Glasses" by norrist. Archer72 said: "Glasses and age" (2026-08-06 11:41:39) hpr4676 (2026-07-06) "HPR Community News for June 2026" by HPR Volunteers. Archer72 said: "hpr4657 :: UNIX Curio #8" (2026-08-02 19:29:26) hpr4677 (2026-07-07) "UNIX Curio #10 - Checksums and Hashes" by Vance. Whiskeyjack said: "Checksums and HPR4677" (2026-07-31 00:37:40) hpr4678 (2026-07-08) "High Resolution Elapsed Time in Shell Scripts" by Whiskeyjack. Archer72 said: "Reply to Whiskeyjack and candycanearter07 " (2026-08-03 10:12:47) hpr4692 (2026-07-28) "Noise Music Tutorial 2: Using Audacity to Make Noise" by TheDUDE. Windigo said: "Audacity for noise music" (2026-08-06 16:09:59) candycanearter07 said: "re: Audacity for noise music" (2026-08-12 18:55:18) This month's shows hpr4696 (2026-08-03) "HPR Community News for July 2026" by HPR Volunteers. Archer72 said: "Amateur Radio Field Days" (2026-08-02 11:50:11) Archer72 said: "hpr4673 First contact" (2026-08-03 10:16:09) candycanearter07 said: "re: mic issues" (2026-08-03 22:21:42) Th3Dud3 said: "response to Kevin not being able to get cream ale" (2026-08-06 00:12:38) hpr4697 (2026-08-04) "Correcting the Dates of Files" by Vance. Jim DeVore said: "Useful episode!" (2026-08-04 10:53:12) Vance said: "Modifying metadata" (2026-08-07 01:44:51) Henrik Hemrin said: "Exif in digiKam" (2026-08-08 19:20:13) candycanearter07 said: "useful!" (2026-08-10 16:08:18) hpr4698 (2026-08-05) "ID3 Tags and Vorbis Comments" by Whiskeyjack. xmanmonk said: "Great episode!" (2026-08-05 15:19:01) candycanearter07 said: "quirks in hpr" (2026-08-05 15:52:18) Whiskeyjack said: "Reply to xmanmonk in HPR4698 - ID3 Tags" (2026-08-06 00:12:26) Whiskeyjack said: "Reply to candycanearter07 in HPR4698 ID3 tags" (2026-08-06 00:28:48) hpr4703 (2026-08-12) "Ebooks and Audiobooks" by Ahuka. candycanearter07 said: "useful!!" (2026-08-12 02:30:58) Archer72 said: "Audiobooks and Audible" (2026-08-12 09:06:40) Jack said: "Misleading" (2026-08-12 17:05:21) hpr4705 (2026-08-14) "Free Software Is Wasted On You Teens" by Trollercoaster. Archer72 said: "Brilliant! " (2026-08-03 14:08:08) Trollercoaster said: "One left in my six pack" (2026-08-14 07:53:38) old guy said: ":-)" (2026-08-14 09:24:15) Trollercoaster said: "old guys together" (2026-08-14 13:14:48) candycanearter07 said: "good satire again" (2026-08-14 21:42:55) Trollercoaster said: "Who's talking about satire?" (2026-08-15 07:54:33) Trollercoaster (our of character) said: "Woopsie" (2026-08-16 19:25:41) hpr4706 (2026-08-17) "Quirks and Customisations" by Lee. candycanearter07 said: "cool ep!" (2026-08-30 20:15:40) hpr4707 (2026-08-18) "UNIX Curio #12 - expr" by Vance. xmanmonk said: "Another great show" (2026-08-18 22:22:56) Whiskeyjack said: "HPR4707 Unix curio - dc" (2026-08-19 14:31:02) Vance said: "dc" (2026-08-20 04:47:32) Whiskeyjack said: "HPR4707 Unix curio - Stack Machines" (2026-08-21 16:00:48) Trollercoaster said: "Suggestion for Linux Curio" (2026-08-27 10:42:43) Whiskeyjack said: "Obscure X Window programs" (2026-08-27 16:16:15) candycanearter07 said: "re: Suggestion for Linux Curio" (2026-08-27 18:13:51) Archer72 said: "re: Suggestion for Linux Curio" (2026-08-28 10:07:31) Vance said: "Thanks for the ideas" (2026-08-28 16:39:28) Whiskeyjack said: "Reply to Vance on episode research" (2026-08-30 04:14:01) candycanearter07 said: "re: re: Suggestion for Linux Curio" (2026-08-30 12:06:31) hpr4708 (2026-08-19) "Programmable Logic Controls - Episode 1" by Whiskeyjack. Archer72 said: "Thanks you" (2026-08-08 10:49:34) Whiskeyjack said: "Reply to Archer72 on HPR4708 - PLCs Episode 1" (2026-08-08 17:11:10) Trey said: "Memories of Ladder Logic" (2026-08-19 13:01:41) Whiskeyjack said: "Reply to Trey on HPR4708 - PLCs Episode 1" (2026-08-20 02:02:44) Trey said: "Cyber in ICS" (2026-09-02 22:31:51) Whiskeyjack said: "Reply to Trey on Cyber in ICS" (2026-09-03 15:24:51) hpr4709 (2026-08-20) "Peertube: my two penneth" by Kevie. xmanmonk said: "Thanks for the episode" (2026-08-20 19:15:57) hpr4711 (2026-08-24) "Second-Hand Phone" by TrumpetJohn. candycanearter07 said: "interesting!" (2026-08-24 19:17:44) Whiskeyjack said: "HPR4711 - TCL Flip phone" (2026-08-24 22:22:11) hpr4712 (2026-08-25) "friedcamp interviews part 1: Wim van Gool" by Kristoff. Archer72 said: "Interview" (2026-08-26 23:11:49) Laindir said: "Fascinating interview!" (2026-08-26 23:18:33) hpr4716 (2026-08-31) "PocketMod" by TrumpetJohn. Kightlinger said: "I love PocketMods!" (2026-08-31 17:35:43) candycanearter07 said: "analog solutions" (2026-08-31 20:52:55) 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-August/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.

  3. Sep 4

    HPR4720: Robert A. Heinlein: Earlier Novels

    This show has been flagged as Clean by the host. Heinlein published his first novel in 1948, and within a decade had published some major works. What distinguishes these early novels from his later ones is that he has not pushed the boundary of what he can write about to the degree he does in the 1960s and later. But there are fine novels in this period. Heinlein’s Earlier Novels During the 1950s Heinlein was busy with his Juvenile series, but also found time to write some adult novels, and some of them are very good. A few of them were expansions of earlier, shorter works that he turned into full novels. Beyond This Horizon (1948) – This is Heinlein’s first novel after the lackluster For Us The Living (which never was published during his lifetime; Heinlein knew it was sub-par). It is set in a future society that is practicing a form of eugenics, with a breeding program designed to produce the perfect human by selecting for health, longevity, and intelligence. The protagonist, Hamilton Felix, is not the one, but he is near to the end. And this society has also made it a point to keep a certain number of people who are not part of the breeding program, as a form control for the experiment. Hamilton Felix is in fact the penultimate step in this program, but has so far shown no interest in marriage or procreation. But in the course of the novel he is persuaded. His children are shown to be the end point of the program at the end of the novel. A sub-plot involves his friend Mordan Claude (in this book everyone puts their family name first) who falls for a woman he meets. When she sneezes, he begins to suspect she is one of the “control naturals”. They are protected, but clearly this is a class society, which is to be expected in any society that practices eugenics, and should be off-limits for Claude. But love conquers all, and then he discovers that she is not a control natural after all, which to my mind is a somewhat weaker outcome.Another aspect of this society is that most people are armed, and dueling is common. This is explained as “An armed society is a polite society,” since if you offended someone you could find yourself in a duel very quickly. A lot of gun enthusiasts have picked up on this and repeated it as if it was revealed truth, but even a cursory examination of societies with a lot of guns shows it to be false. Sixth Column (1949) – This novel was originally a serial written in 1941, when the Sino-Japanese war was in full swing, and this motivates some of the ideas in this book. The setting is a United States that has been conquered by the Pan-Asian Federation. This Federation had previously absorbed the Soviet Union and India, and is portrayed in very much Yellow Peril manner. John W. Campbell had a lot to do with this, and it makes the novel something that you can skip without losing much. The Pan-Asians regard the Americans as slaves. And their policy towards their slaves is “Three things only do slaves require: work, food, and their religion.” In an American military outpost hidden in the mountains of Colorado a miracle weapon is found that can kill, and it can somehow be tuned to only affect the Asians and not the Americans. Since the Pan-Asians have allowed religion (better to pacify the slaves), the Americans create a religion and use that to infiltrate the Pan-Asian facilities. Heinlein himself had a low opinion of this novel, and deservedly so. The Puppet Masters (1951) – This novel is a product of the paranoia of the times regarding Communists. But this novel is more of an allegory than a direct anti-Communist screed. It is fundamentally about “the enemy within”, in the form of alien parasites called slugs that can take over a human by controlling the nervous system, making the human a powerless slave to the alien. And they are attempting to conquer the world, though all of the action we see takes place in the United States. This is essentially The Body Snatchers plot, and has been done many times. But both this novel and the previous Sixth Column reflect the feeling of paranoia prevalent in society when people thought there were communists under every bed looking to corrupt the youth and subvert The American Way of Life. And it is notable that the organization that leads the fight against the slugs is a top secret outfit established without the knowledge of Congress and responsible only to the President. Double Star (1956) – This is when Heinlein as a novelist starts to really click, and it was shown by his winning his first Hugo for best novel. The plot is somewhat reminiscent of Prisoner of Zenda. In a future solar system, Earth, Venus, Mars, and the Jovian satellites are united under a parliamentary democracy, which is in turn under a constitutional monarchy. Think of it as similar to the UK, only in this case it is the House of Orange that are the monarchs. A politician named John Joseph Bonforte is the leader of the Expansionist coalition, and one of the most prominent politicians in the solar system. And he has been kidnapped sat a crucial time. His staff find an actor, stage name The Great Lorenzo, who is similar enough physically to impersonate Bonforte, while they try to get the real Bonforte back. They do succeed, but he has been very badly treated by the kidnappers, so the actor has to continue for the election campaign. And he wins the election, but the real Bonforte dies. The actor then continues to impersonate him to the point of really becoming him. The two things that make this novel so interesting are first, the focus on acting as seen through the eyes of Lorenzo; and second, the focus on the machinery of politics. And this draws upon Heinlein’s own experience in electoral politics. Though he was not successful in getting elected, he clearly had absorbed a lot about the how-to of the process. And he did write a non-fiction book called Take Back Your Government (1992), which was published posthumously. It was subtitled A Practical Handbook for the Private Citizen Who Wants Democracy to Work, and was originally written in 1946. It was based on his experience with EPIC and in trying to get Upton Sinclair elected Governor of California in 1934. The Door Into Summer (1957) – This is another good novel, which features several themes that would reappear through Heinlein’s work. The first is that Heinlein was a very confirmed cat lover. The title comes from a cat who went from door to door in the middle of winter, trying to find the door into summer. Second, the protagonist is an engineer, which is of course Heinlein’s background. The third is the time travel element. People can travel into the future through a type of suspended animation called Cold Sleep. But for the purposes of the plot a scientist has invented a time travel device that sort of works. It sent a grad student named Leonard Vincent a few centuries back in to Italy where he became Leonardo da Vinci. But it sends our hero, Daniel Boone Davis, back exactly where he wanted to go. We see a few things in this novel that are of interest. First, the cat, Pete, has the full name of “Petronius the Arbiter”, who was the author of the Satyricon, so Heinlein’s interest in sex is starting to make an oblique appearance. Second, when Dan goes back in time, he lands in the middle of a nudist camp, and that is also something Heinlein was very interested in.The plot can be summarized as Dan gets robbed of his inventions by his business partner and his secretary/fianceé, gets put into Cold Sleep, then goes back in time to just before he got robbed and fixes things to his satisfaction, then takes the Cold Sleep again to finish his plans. It is a pretty good yarn. Methusaleh’s Children (1958) – This was originally a novella written in 1941, then expanded into a novel. It is part of the Future history. It introduces Lazarus Long, who would go on to be Heinlein’s alter ego through many of his future books, and thus implicitly makes those books part of the Future History, though most scholars will dispute this. What cannot be disputed is that this novel is a cornerstone for where Heinlein would go in many of his future stories.The story begins with a successful businessman named Ira Howard who dies of old age at around the age of 49 in the 19th century. In his will he leaves his estate to trustees with the mandate to find a way to extend human life span. The best they can come up with is to encourage (financially) people who had long-lived grandparents to marry each other and have children. They carry this on and by the 22nd century the Howard Families, as they call themselves, have an average life span of 150 years. But they have to hide this form the rest of society, and arrange from time to time to “die” and then become someone else. This masquerade helped them survive the years of Nehemiah Scudder and his successors, but a few of them reveal themselves during the Covenant government. This has a bad result because people want the secret that they assume the Howard families are hiding, and they might be willing to kill to get the secret. So the Howard families steal a starship and make their escape. One of the people onboard is Andrew Jackson “Slipstick” Libby, who we first met in the short story Misfit, and he manages to come up with a Faster-Than-Light drive. They finally decide to go back to Earth, where they discover that scientists have found ways to prolong human life and they are no longer enemies, in fact they are welcomed for bringing the FTL drive.This is definitely a must-read novel for anyone who wants to get into the Heinlein universe. So many other works are based on it. Links https://en.wikipedia.org/wiki/Beyond_This_Horizon https://en.wikipedia.org/wiki/Sixth_Column https://en.wikipedia.org/wiki/The_Puppet_Masters https://en.wikipedia.org/wiki/Double_Star https://en.wikipedia.org/wiki/Take_Back_Your_Government https://en.wikipedia.org/wiki

  4. Sep 2

    HPR4718: Programmable Logic Controls - Episode 2

    This show has been flagged as Clean by the host. -------------------- 01 Introduction This is the second episode in an 8 part series. 02 In the previous episode we discussed the predecessors of PLCs, in particular relay logic. In this episode we will discuss how relay logic came to be expressed in software rather than in actual hardware components. 03 The topics to be covered include * Early computers in industry. * The first PLC. * PC versus PLC - what's in a name. * Who the major brands are. * What does a PLC actually look like. * Machine architecture. * PLC programs. * The scan. * PLC programming languages. * Relative popularity of PLC programming languages versus more conventional computer programming languages. -------------------- 04 Early Computers in Industry Computers came to be used in industry fairly early on. Minicomputers were used in some large industries to control things like electric power plants. For example, the DEC PDP8 was used to control the refuelling machines in CANDU nuclear power plants. These would load and unload fuel from the reactor, which happens continually on a daily basis while the reactor is running. 05 The first microprocessor based computer sold on the commercial market was the MICRAL from France, based on the Intel 8008. It was sold as a cost effective replacement for minicomputers used in industry. It preceded what are generally considered to be the first Personal Computers. So you can see that industry were not reluctant to adopt new technology. 06 However, mini computers were large complex systems that did not fit well into a factory floor. They had particular niches in very large complex integrated systems, but were not suited to controlling many individual machines in a factory that produced things like automobiles or appliances. 07 What was needed was something that would fit into a standard electrical enclosure, withstand the temperatures found in a factory, could stand up to vibration and noise, was tolerant of voltage fluctuations, interfaced directly to sensors and actuators, and could be readily programmed by engineers, technicians, and tradesmen who were familiar with the processes to be controlled, but had little or no experience with computers. 08 This required a complete integrated package covering hardware, software, and product distribution through industrial supply retailers. Something that could meet these criteria is what was needed to become the PLC. -------------------- 09 History Many histories point to a US developer that became Modicon. However, their first hardware was more a proof of concept than a viable commercial product. In fact multiple companies in the US, Europe, and Japan were working on the problem and released comparable products all at around the same time in the early 1970s. 10 The idea preceded the implementation by a number of years. For example, General Motors had asked industrial control equipment suppliers in the mid 1960s for some sort of programmable control device to replace relay logic. This showed potential suppliers that there was a market for this sort of thing, and gave them a clearer idea of what customers were looking for. 11 What made this possible was the development of the first 8 bit microprocessor in that time period, combined with readily available bit slice processors from the minicomputer industry and other components. 12 People knew what to do, the problem was waiting for the development of suitable component hardware. Minicomputers were already being used in industry, but were normally located in control rooms. PLCs were an effort to take that technology out of control rooms and put it on the shop floor. 13 PC Versus PLC - What's in a Name In the early days, these systems were known as either PLC, which means "Programmable Logic Controller", or PC, which means "Programmable Controller". Different vendors favoured different terminology, but both were common. I have a book which was at one time one of the standard reference handbooks for this industry which was published in 1989, and refers to them as Programmable Controllers, or PCs. 14 The term PC was also used to mean "Personal Computer", but that wasn't really a problem in the early days. However, a certain large company decided to call their entry into the personal computer market the "IBM PC", and suddenly "PC" became a generic term for desktop computers. 15 After a long struggle to keep referring to their products as "PCs", even the biggest vendors caved in and gave up the fight and switched to using the "PLC" term. I will therefore use the term "PLC" in this podcast series even when talking about products which were originally called "PCs" at the time they were introduced. 16 Who the Major Brands Are The companies that came to dominate the industry fairly early on were generally companies that already made industrial electrical hardware. These were Siemens Allen Bradley, later known as Rockwell Schneider Mitsubishi Omron 17 These are still the dominant companies in the business, although there are many small brands, particularly at the cheaper end of the market. All of them were suppliers of a wide range of industrial control hardware, such that you could build all or nearly all of the parts of your control system using only their products. 18 Each of these sells an integrated hardware and software package, including development software, that is completely proprietary. If you thought that the mainframe business had a lot of vendor lock-in, you haven't seen the industrial market. -------------------- 19 What Does One of These Things Actually Look Like? At this point you are probably still very confused as to what a PLC actually is. I will attempt to describe one in basic terms by giving an example of one. The smallest and simplest ones are what are termed "shoebox" PLCs. These are basically a rectangular box with a plastic case. 20 Here are the dimensions for a typical low end model, a Mitsubishi FX3U-32M. According to specs in the manual, it is 150mm wide, 90mm high, and 86mm deep. 21 It can be mounted to the panel in an electrical enclosure by snapping it onto what is termed a DIN rail. DIN rails are standard mounting systems which use a strip of metal which is U shaped with a lip at the top of each end of the U. You screw the DIN rail to the electrical panel in the enclosure, and most industrial components such as PLCs, terminal blocks, circuit breakers, and all sorts of other things will simply snap onto it and be ready to wire together. 22 Along the top and bottom of the PLC are terminals to which you can attach wires from the things you want to sense or control in the rest of the machine, such as push buttons, pilot lights, proximity sensors, and valves. 23 Inputs are along the top, and outputs are along the bottom. The FX3U-32M has 16 inputs and 16 outputs. These I/O can be 24 volts DC, or 100 to 120 volts AC, depending on the model. Alternatively it may have small relays for outputs. While AC I/O once predominated, 24VDC became the standard in most industries several decades ago as it interfaced with electronic devices more readily and also allowed for cheaper and more compact wiring. 24 More inputs and outputs can be added by connecting additional I/O modules to the main PLC next to it on the same DIN rail, up to a total of 256 I/O The connection is typically via short ribbon cables which plug into the adjacent module. These I/O modules look like the main PLC, but just add I/O. 25 Inside the PLC are a CPU, memory, and firmware. This model has 64K "steps" of memory, which can be thought of as how many instructions you can have. The program runs in RAM, but you can add a small flash memory device to save the program to. There is a run/stop switch that allows you to start or stop the user program. There is a port that you can use to connect the PLC to a laptop computer with a cable so you can download your program to it. 26 The biggest part of the market for PLCs is for these "shoebox" style. However, there are bigger ones as well which have more I/O, more memory, faster CPUs, etc. These are meant for tasks such as coordinating large assembly lines and things like that. These are what are termed rack systems, where the rack is an empty box which is open at the front and has a backplane bus running along the back. You plug the main CPU into the bus, normally in the leftmost position, and then plug I/O modules into the rack. The I/O modules are tall, thin, fully enclosed boxes with the I/O terminals along the front. 27 You should have a rough idea of their appearance at this stage, so I'll leave the physical description aside for now and go on to the concepts behind how they actually work and what makes them different from something like say a Raspberry Pi. -------------------- 28 Machine Architecture It is not really the hardware which defines the PLC. Rather, it is the software system architecture. Every PLC that I am aware of has a common set of features. 29 Data Table A data table is simply a block of memory which may or may not be subdivided into different parts. All logic, and all, or nearly all, I/O works by writing to and reading from addresses in the data table. 30 I/O Every input and output point maps to a fixed memory address in the PLC. To read the state of an

  5. Sep 1

    HPR4717: Visit with a blind Ham operator

    This show has been flagged as Clean by the host. Hi, this is Archer72 for another episode of Hacker Public Radio. In this episode, it is my first experience troubleshooting with an experienced blind Ham operator who is located 20 miles away from my hometown. When traveling there, I could not miss his house, which was the only one off the main road with an estimated 50 foot antenna. That’s 15 meters for the rest of the world. This antenna was intended for the HF high frequency band, for which the local Ham radio club had very recently extended to this height. The target radio bands are 20, 40 and 80 meters. I had missed a great opportunity to record the session so wanted record (and write this) while it was fresh on my mind. Several months later… This particualar operator (KG4QWH) (Kilo-Golf-Four-Quebec-Whiskey-Hotel) was a radio operator for the local emergency services for 22 years, after which the new company decided to cut back on staff. A local broadcast radio station was hiring soon after and was using some version of Linux which was not accessible for a blind user like himself. This conversation was started after I was asked about his computer that he was trying to force update on older hardware from Windows (7?) to Windows 11, in true hacker fashion. While talking about the Linux situation and also the Windows side, it brough to light the glaring (near) ommision of accessibility software in both camps. On the Windows side, which is more familiar to my friend, is Jaws. Great software, but year after year the barrier of cost is getting more, and on the Linux side accessibility is not looking any better. While cost is not a factor in using it, and this is only coming from me, the voices could be better. Piper is an option for natural sounding voices, but has yet to be integrated into a FOSS screen reader AFAIK. On the positive side of accessibility, the Kenwood radio (model TS-590S) has the option to add a module to give an audible description of the buttons being pressed, and at the time there was gnother operator who came through and talk him through some receiver settings. The reason I went there is the first place was that the Kenwood microphone was causing noise to come across the speaker when he keyed up the mic. Initially the proprosed solution was to switch two wires inside the Kenwood microphone. I was asked about this ahead of time so was prepared with an electrical box with miscellaneous low voltage wires and stripping tool, also a Pincil soldering iron equiped with a USB C 100 watt power supply. To fix the problem on the Kenwood MC-60 microphone, you need to swap the wires so that mic hi is on Pin 1 and mic low (shield) is on Pin 7. This is often necessary due to factory wiring errors. After finding out that the proposed solution was to open the mic, which required a heat gun the soften the locktight, I tried another route. My friend had a toroid choke handy, and I coiled the feed line to the back of the radio around the toroid. (8 - 10 times?) This had no effect. Next to try was to ground the mic from the outside, which there was a bare metal screw on. This connected to a dedicated ground on the back of the Kenwood TS-590S radio. This seem to suppress the hum when using PTT. The rest of the evening (the best time for HF), Matthew was able to make contacts on 40 meters. Great to meet you as well my friend and I appreciate you coming up. I was able to talk on 40 this evening with no problems. I reached several in Kentucky Indiana and I even reached Kansas. Come to think of it. I was even able to reach someone on the Jersey shore. References Blind Hams Network New CQ Blind Hams Podcast: CQBH 011 TS-590SG Tutorial by N3AIN New CQ Blind Hams Podcast: CQBH 012 TS-590SG tutorial by N3AIN KENWOOD TS-590S instruction manual KENWOOD VGS-1 instruction manual KENWOOD Communications Microphone MC-60A Instruction Manual Image of a 15 meter HF antenna on a two story house in Kentucky. Provide feedback on this episode.

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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.

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