Hacker Public Radio

Epizodes

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  HPR4732: Webp 22.09.2026

  Webp is meant to replace GIF, JPEG, and PNG. Its features include: Lossy compression Lossless compression Metadata, including Exchangeable Image File Format (EXIF) and Extensible Metadata Platform (XMP) Transparency (an "alpha channel") Embedded ICC (International Color Consortium) profile Multiple frames (animation) The typical expectation is to achieve equal or better visual quality as a JPEG or PNG or GIF, but with a savings of 25% to 35% on file size. This is famously difficult to measure, because if you concede to an equal file size, then the quality ought to be better, but there is a "ceiling" to quality that can be detected by the majority of human eyes. So the metric is the unmeasurable: How good does it look to you? If it looks as good or better, and the file size is smaller, then it can be said that the format is superiour. The best and most common test is to look at an image compressed with JPEG or PNG compression, and then look at the same image compressed by WEBP. If you can't tell the difference, and the file size of WEBP is smaller, then it's an improvement for disk space and bandwidth. WEBP is an 8-bit format (based on the VP8 video codec) and lacks support for 10-bit, 12-bit, or 16-bit colour. Specifically, WEBP is YUV420, where Y is Luma (brightness and darkness), and U and V are Chroma (colour). Each 8-bit pixel in the UV (Chroma) corresponds to a 2-by-2 block of 8-bit Luma pixels, or in other words, Chroma gets half the resolution of Luma. This is not uncommon, because how sharp an image appears to the human eye is mostly (not entirely, to be fair) influenced by Luma. Our eyes differentiate bright from dark better than our eyes perceive subtle shifts in hue. The ICCP chunk starts with a 4-byte declaration (the ASCII string "ICCP"), then a 32-bit integer representing the length of the payload, then the payload (the ICC profile specification according to the International Color Consortium), and then optionally a byte to pad the header. The embedded ICC profile can define any old colour space you want. If none is defined, sRGB is assumed. The libwebp library only parses the ICC profile, it doesn't actually handle conversion. That's left to the client application, which is why you might get a notice sometimes in GIMP or a similar application about a colour space mismatch. (It's generally safe to convert to your current colour space, and if it's not then you'd know it because you're working in a multimedia production house where colour spaces and colour profiles are significant.) Converting to WEBP is available in most applications, at this point, including Image Magick and the cwebp command. Image Magick: $ convert foo.tiff foo.webp Or using cwebp with -q for a quality 0 (low) to 100 (high), and -o for output: $ cwebp foo.tiff -q 60 -o foo.webp Test images are available from a Mozilla test suite. Or you can test on a Hacker Public Radio image, such as the screenshot of the upload
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  HPR4731: A Website Hacked 21.09.2026

  [WP2Shell is] a pre-authentication RCE in WordPress Core . The attack has no preconditions and can be exploited by an anonymous user in a stock install of WordPress with no plugins. - from wp2shell.com Wordpress.org - https://en-gb.wordpress.org/ Searchlight WP2Shell Website - https://wp2shell.com/ CVE-2026-63030 - https://nvd.nist.gov/vuln/detail/CVE-2026-63030 CVE-2026-60137 -
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  HPR4730: Playing Civilization VI Part 1 18.09.2026

  Civilization VI, made a number of changes, and one of the biggest was the introduction of Districts. Buildings that perviously would have just been part of the city now had to be built in special districts, and the game limited how many of them you could build in any one city. This forced you to make choices, and making choices is the heart of the Civilization series. Playing Civilization VI, Part 1 Districts As we have said before, the rule for each new version of Civilization is that 1/3 stays the same, 1/3 is tweaked, and 1/3 is new. So among things staying the same is the Hexagonal grid first introduced in Civ V, along with the usual roaming tribe in 4000BC. But the handling of terrain that a city can use has changed. The old Big Fat Cross was dropped in Civ V, and replaced with a large Hexagon. And how you use the terrain has changed. In older versions of Civilization, the terrain was mostly used for either farming or mining. It was all about resource extraction, in other words. All of the Buildings you constructed you could think of as abstract, or as all living in the City Center. The only reason you had for making different choices in the Build queue was if you didn’t have enough time or resources to build everything. As a result, many cities looked very similar in what got built. You would put a Granary in each city to help it grow, a Barracks in each to build your troops, a Temple in each city to gather Faith, and so on. There wasn’t much a decision here, or at least not enough to satisfy Ed Beach, the Chief Designer of Civ VI. So he came up with a new land use system involving Districts. With this system, you had to allocate land in your city for most things you would build. If you wanted to focus on Science, for instance, you would have to allocate a tile to a Campus district. Then, inside this district you could build a Library, a University, an Obervatory, and a Research Lab. But that is the only place they could be built. Furthermore, to prevent you from building every district, they limited the number of districts each city could have based on its population. You can always build one district with a new city, but to build another you need to get to a population of 4, and you get the ability to add a District with each additional increment of 3, so at Population 7, 10, 13 you get the ability to add a District. And these Districts have to be constructed as part of the normal city Build process. So in the above example, you would first have to build the Campus district, and when that was complete you could then build the Library to put inside it. And for both the Districts and the buildings inside of them you need to research certain technologies before they become available to you. Where to locate your districts becomes an issue as well. First of all, the tiles available to you are also your stock of tiles for building Farms and Mines, so you need to make choices here. Of course, making choices is the basis them of all Civilization games. Then there are the adjacency effects of terrain tiles. Both Campus (Science) and Holy Site (Faith) districts benefit from being adjacent to Mountains, and the adjacency effects are cumulative, so a tile with mountains on 3 sides can have major bonuses. But since this affects both kinds of Districts, again you have to make a choice. If you are aiming at a Science Victory, or a Religious victory, the choice will be easier, but in case you need to choose. As to placing a District, when you decide to build one you will get a highlight on the map of locations that are permissable. But if you have several such sites, you need to choose which one fits your strategy best. District Types There are a lot of Districts you can build and listing every one of them here would be tedious. Some are only relevant to late-game situations, others address issues like Housing and Amenities, which we will
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  HPR4729: Living under a rock 17.09.2026

  Living under a rock Living under a rock and feeling completely out of touch with everyone else. I rarely buy new items unless I have to due to me being a tight Scotsman however recently I have bought a few new items and their performance surprised me somewhat and made me feel a little like I’ve been living under a rock. I thought this would make a good topic for an HPR show. SSD 256GB USB stick (Refer to picture 1 and 2) Wikipedia article about SSD’s This is my first ever SSD, its made by Netac It is a double ended USB thumb drive with a USB A one side and USB C the other. I couldn’t believe how fast it was on my Mac; copying a 700MB file seemed almost instantaneous. I couldn’t actually believe it had copied the file and thought it had been an error! I tried it on my old PC running Ubuntu and was getting 40MB/sec write speed! Even more surprising was copying files between a USB hard drive and the SSD usb stick, with both connected to my Raspberry Pi. This was achieving a sustained write speed of 60MB/Sec. I’ve never seen anything faster than 40MB/Sec. I think I’ve been living under a rock for a number of years while the rest of the world moved on! My only concern with this technology is that I am not totally convinced about the long term reliability of SSDs. The SSD is great for transferring files back and fourth to different devices however for now I’ll stick to spinning hard drives on my PC for long term storage as speed is not so important to me. Picture above shows my new Netac USB SSD stick Picture above shows how the USB SSD stick opens LED Lantern (Refer to pictures 3) This LED Lantern was recommended by my mother We purchased it from Tesco’s. Tescos in the UK is a British multinational groceries and general merchandise retailer I think it only cost me £8.40. (UK pounds) It even came with AA batteries ! The LED Lantern is 9 inches x 3.5 inches The light output is phenomenal. It is diffused and fills a good-sized room with light. It has a low output mode, which is still very usable and will increase the running time. It also has a flashing option, which is likely only useful in an emergency. I think the reason they were selling them so cheap was that the date code of the included AA alkaline batteries was almost out of date. Alkaline batteries can have a very long shelf life. Picture above shows the new LED latern that I bought from Tescos Super Store in the UK Laser printer HP M209dw
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  HPR4728: Programmable Logic Controls - Episode 3 16.09.2026

  -------------------- 01 Introduction This is the third episode in an 8 part series. 02 In the previous episode we covered * The early history of computers in industrial control * The early history of PLCs, including how they got their name * Who the major brands are * What they look like physically * A basic description of the abstract machine architecture * A very brief look at what a PLC program is like * The scan concept * The main PLC programming languages * The minor PLC programming languages * The relative popularity of each of the programming languages 03 In this episode we will begin by taking a look at one of the early PLCs from the era when they first began seeing widespread use. I will not even attempt to try to be comprehensive, I will just give a broad overview in the limited time I have available here. I have started with an older model because its simplicity and limited features allow for an easier introduction to the topic. -------------------- 04 Allen Bradley PLC/2 The Allen Bradley PLC/2 was introduced to the market in 1977. It was not their first foray into this field, but it was their first really successful one. I am not aware of a comprehensive history of their early product line, but one of their early major selling models was the PLC2/30. This is also known as their 1771 series. -------------------- 05 Physical Layout The CPU module was a large metal box which sat beside the I/O rack and connected to it with a cable. The I/O rack was a box with an open front and an series of slots into which tall narrow boxes containing the I/O could be slotted. 06 A backplane ran across the back, connecting the I/O to the CPU. Multiple racks could be connected together by cables. For the PLC2/30, you could have a maximum of 896 digital I/O points. 07 Racks were 315mm high, and between 247mm to 610mm wide, with racks coming in 4, 8, 12, and 16 slot varieties. The CPU was the same height as the rack and roughly square in outline. 08 As micro electronics advanced, the CPU module was able to be shrunk down in size such that it would fit into a slot in the rack, which became the norm for PLCs. -------------------- 09 The Electronics Inside Early model PLC/2s used some sort of 8 bit processor, some sources say an Intel 8080. 10 They also used four AMD 2900 bit slice processors as a logic co-processor. If you are not familiar with bit slice processors, these are chips which are like a 4 bit vertical slice through a processor, and can be joined together with logic chips to form a complete CPU. These are what were used to construct minicomputers. 11 They were used as coprocessors in early PLCs because microprocessors on their own were simply too slow to handle running the user program rapidly enough to allow a useful size program. One or more microprocessors were used as well in order to coordinate the overall operation and system management. 12 As microprocessors grew faster and more powerful, the need for logic coprocessors declined and they were eventually dropped. Early versions used magnetic core memory. Later ones switched to some sort of solid state RAM, probably static RAM of some sort. 13 Details of what sort of processors are ins
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  HPR4727: friedcamp interviews part 4: The free Lantern 15.09.2026

  jasper from the Free Latern https://www.thefreelantern.com/ LyricConductor https://github.com/jnuyens/LyricConductor ModuleJail: https://www.modulejail.com https://github.com/jnuyens/modulejail Smart Dinosaur - Space for Fantasy Youtube: https://www.youtube.com/watch?v=qnUyW2yiiwo&list=OLAK5uy_kCrIROefktTWed3iPyDGhCUKl4gTvqXDU Spotify: https://open.spotify.com/album/3J2qdIgJFtk78O5IhYWbOH?si=eba8037fe0b34339
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  HPR4726: Trurl's intro show 14.09.2026

  Introduction & Setting : Recorded on a sunny August afternoon in a Merton garden with Trurl exploring a wide-ranging philosophical and analytical journey through mathematics, games, and literature. Literary & Sci-Fi References : Stanislaw Lem : Discussion of the robot character Trurl from The Cyberiad , who alphabetically creates everything before reaching the letter "N" for "nothing" and destroying everything. Learn more about Lem on Wikipedia . Vladimir Nabokov : Analysis of The Luzhin Defense , a novel exploring chess obsession, psychological breakdown, and the "horror of chess." Explore the book on Wikipedia . Edgar Allan Poe & Thomas Hobbes : Discussion on 19th-century precision in writing, stylistic inflections, and the value of rigorous language. Martin Amis : Praise for his modern precision, with highlights including Money and Information . Core Philosophical & Mathematical Themes : Socratic Epistemology : Exploring the ancient Greek view from Plato's dialogues that equates knowledge directly with practical skill. Active vs. Empirical Learning : Trurl's theoretical aversion to traditional science labs in favor of pure conceptual frameworks, contrasted with hands-on computational tinkering. Stephen Wolfram : Discussion of A New Kind of Science and the computational approach to universal systems. Applied Puzzles & Strategic Games : Chess Ratings : Investigating the rating system, Elo mechanics, and statistical anomalies suggesting top players are statistically underrated. The Drake Equation & Astrobiology : Quantitative modeling of extraterrestrial life inspired by Stephen Webb's If the Universe Is Teeming with Aliens... Where Is Everybody? . Economics & Libertarianism : Transition from early socialist upbringing to decentralized economic structures, cryptocurrency architectures, and the Lightning Network.
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  HPR4725: HPR Beer Garden - Tasting and reviewing beers 11.09.2026

  In a bonus episode for the reserve queue, Kevie and Dave talk about how they review beers: Aroma - what do you smell from the glass and bottle or can Taste - take a sip, swirl it around your mouth and allow it rest a second before drinking; don't gulp. What flavours are you getting. Wait - What flavours are appearing in the aftertaste. Opinions - what are your personal thoughts on this beer. Score - pick a score and rarely give any beer full marks. Connect with the guys on Untappd: Dave 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/
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  HPR4724: HPR Beer Garden 19 - Lager 10.09.2026

  As we are currently going through a warm patch (well, at the time of recording anyway), the HPR Beer Garden returns to provide some refreshment in the heat with a glass of cold and refreshing lager. Dave chooses Super Bock from Portugal, whilst Kevie picks City Limits Amber Lager from the tiny Dog Falls Brewing Co in Inverness. Connect with the guys on Untappd : Dave 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/ Upcoming beers: Mild Bitter Pale Ale
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  HPR4723: friedcamp interviews part 3: The fried telephone system 09.09.2026

  Lieven Blancke: https://mastodon-belgium.be/@lieven asterisk: https://www.asterisk.org/ Asterisk audio files: https://downloads.asterisk.org/pub/telephony/sounds/ Audio of PSTN call: https://en.wikipedia.org/wiki/File:1TR110-1_Kap8.3_Freiton1.ogg