{
  "version": "1.0.0",
  "segments": [
    {
      "speaker": "Josh",
      "startTime": "1.009",
      "endTime": "6.537",
      "body": "Back in college, one of my classes dealt with circuit design. The hands-on lab was building"
    },
    {
      "speaker": "Josh",
      "startTime": "6.537",
      "endTime": "13.453",
      "body": "a robot from scratch. Well, mostly from scratch. The first step was to design the printed circuit"
    },
    {
      "speaker": "Josh",
      "startTime": "13.453",
      "endTime": "21.925",
      "body": "board, PCB, and build it. We were given a plain 3x5 inch or 8x13 centimeter blank"
    },
    {
      "speaker": "Josh",
      "startTime": "20.916",
      "endTime": "27.502",
      "body": "link PCB. The board starts out as a flat piece of fiberglass with a thin layer of copper on top."
    },
    {
      "speaker": "Josh",
      "startTime": "27.922",
      "endTime": "33.828",
      "body": "To create our circuit, we transferred our design onto that copper layer with a protective film"
    },
    {
      "speaker": "Josh",
      "startTime": "33.828",
      "endTime": "40.154",
      "body": "that covered the parts we wanted to keep. Then the board went into an acid bath which ate away"
    },
    {
      "speaker": "Josh",
      "startTime": "40.154",
      "endTime": "47.261",
      "body": "all the uncovered copper, leaving behind just the traces that made up our circuit. This process is"
    },
    {
      "speaker": "Josh",
      "startTime": "47.261",
      "endTime": "53.647",
      "body": "called etching and when it was done, we cleaned the board, drilled any holes we needed, and soldered"
    },
    {
      "speaker": "Josh",
      "startTime": "53.647",
      "endTime": "61.794",
      "body": "all the components on. The capacitors, resistors, chips, and everything else. We then built the rest"
    },
    {
      "speaker": "Josh",
      "startTime": "61.794",
      "endTime": "68.3",
      "body": "of our robot and used our PCB to control it. This was a pretty simple board I made. It only handled"
    },
    {
      "speaker": "Josh",
      "startTime": "68.3",
      "endTime": "75.667",
      "body": "a few basic functions and had just a handful of traces, nothing fancy. But what's cool about it"
    },
    {
      "speaker": "Josh",
      "startTime": "75.667",
      "endTime": "82.594",
      "body": "is that this same process is how real motherboards are made, just on a much larger scale. The"
    },
    {
      "speaker": "Josh",
      "startTime": "82.594",
      "endTime": "87.999",
      "body": "difference is that they use much smaller, more precise components, and the soldering is done"
    },
    {
      "speaker": "Josh",
      "startTime": "87.999",
      "endTime": "94.565",
      "body": "with incredible accuracy by machines. Not by some college kid with an $8 soldering iron."
    },
    {
      "speaker": "Josh",
      "startTime": "95.286",
      "endTime": "99.149",
      "body": "The part that is essential for all your computer components to communicate,"
    },
    {
      "speaker": "Josh",
      "startTime": "99.59",
      "endTime": "106.977",
      "body": "on this episode of in the shell. The wrong thing to do is just go out and buy a computer and then"
    },
    {
      "speaker": "Josh",
      "startTime": "106.977",
      "endTime": "111.661",
      "body": "learn about it. You'll learn, but you'll learn a lot of things that maybe you didn't want to learn."
    },
    {
      "speaker": "Josh",
      "startTime": "111.821",
      "endTime": "117.987",
      "body": "A computer that you buy today will likely be obsolete six months from now and there's not a"
    },
    {
      "speaker": "Josh",
      "startTime": "117.987",
      "endTime": "124.834",
      "body": "dang thing that you can do about it. A motherboard is the main circuit board that holds and connects"
    },
    {
      "speaker": "Josh",
      "startTime": "124.834",
      "endTime": "131.2",
      "body": "all the core components of a computer. Think of it as the PC's central backbone or nervous system."
    },
    {
      "speaker": "Josh",
      "startTime": "132.04",
      "endTime": "138.446",
      "body": "It's the large flat board you see when you open a desktop computer with the CPU, memory sticks,"
    },
    {
      "speaker": "Josh",
      "startTime": "138.647",
      "endTime": "144.852",
      "body": "and other cards or components plugged into it. In laptops and smartphones, it's usually a smaller,"
    },
    {
      "speaker": "Josh",
      "startTime": "145.113",
      "endTime": "151.138",
      "body": "densely packed board, often called a logic board, which is Apple's term, or just system board,"
    },
    {
      "speaker": "Josh",
      "startTime": "151.138",
      "endTime": "157.444",
      "body": "but it serves the same purpose, tying all the pieces together so they can communicate and work"
    },
    {
      "speaker": "Josh",
      "startTime": "157.444",
      "endTime": "164.111",
      "body": "as one. And why the name motherboard? The motherboard is the mother to all smaller boards."
    },
    {
      "speaker": "Josh",
      "startTime": "164.551",
      "endTime": "170.677",
      "body": "You can plug in daughter boards, like expansion cards, into it to add functionality, hence the naming."
    },
    {
      "speaker": "Josh",
      "startTime": "171.558",
      "endTime": "178.204",
      "body": "Early computers had simpler main boards that weren't easily extensible, but once engineers enabled"
    },
    {
      "speaker": "Josh",
      "startTime": "178.204",
      "endTime": "185.831",
      "body": "plugging in add-on cards, the term motherboard stuck. So what's actually on a motherboard and how does it"
    },
    {
      "speaker": "Josh",
      "startTime": "185.831",
      "endTime": "193.538",
      "body": "work? A motherboard is a printed circuit board, PCB, a hard, thin board made of non-conductive material,"
    },
    {
      "speaker": "Josh",
      "startTime": "193.919",
      "endTime": "201.366",
      "body": "usually fiberglass or plastic, with layers of copper pathways printed onto it. Those copper pathways,"
    },
    {
      "speaker": "Josh",
      "startTime": "201.526",
      "endTime": "207.692",
      "body": "called traces, are like tiny highways for electrical signals. They link all the different sockets and"
    },
    {
      "speaker": "Josh",
      "startTime": "207.692",
      "endTime": "214.798",
      "body": "components on the board, allowing data and power to flow between the CPU, memory, storage, and"
    },
    {
      "speaker": "Josh",
      "startTime": "214.798",
      "endTime": "222.185",
      "body": "peripheral devices. Importantly, the motherboard doesn't compute or store data the way a CPU or"
    },
    {
      "speaker": "Josh",
      "startTime": "222.185",
      "endTime": "227.37",
      "body": "hard drive does. Instead, it distributes power and data between those components."
    },
    {
      "speaker": "Josh",
      "startTime": "228.711",
      "endTime": "233.956",
      "body": "When you plug in the computer's power supply to the motherboard, that power is routed through voltage"
    },
    {
      "speaker": "Josh",
      "startTime": "233.956",
      "endTime": "240.222",
      "body": "regulators on the board to the CPU and other components. The motherboard provides the physical"
    },
    {
      "speaker": "Josh",
      "startTime": "240.222",
      "endTime": "246.768",
      "body": "connections and communication channels so that your CPU can talk to your RAM through a memory bus built into"
    },
    {
      "speaker": "Josh",
      "startTime": "246.768",
      "endTime": "254.796",
      "body": "the board or send data to your storage drives via SATA or NVMe connections. Every major component either"
    },
    {
      "speaker": "Josh",
      "startTime": "254.796",
      "endTime": "262.163",
      "body": "plugs into the motherboard or is built onto it. For example, the CPU sits in a socket on the"
    },
    {
      "speaker": "Josh",
      "startTime": "262.163",
      "endTime": "269.114",
      "body": "the board, memory modules snap into slots, and your SSD or hard drive connects via a cable or"
    },
    {
      "speaker": "Josh",
      "startTime": "269.114",
      "endTime": "277.029",
      "body": "M.2 slot on the board. Even external devices, like a keyboard, mouse, or monitor, ultimately connect"
    },
    {
      "speaker": "Josh",
      "startTime": "277.029",
      "endTime": "283.257",
      "body": "into the motherboard's ports. Without the motherboard acting as a hub, all those parts"
    },
    {
      "speaker": "Josh",
      "startTime": "283.257",
      "endTime": "289.324",
      "body": "would just be isolated bits. There'd be no way for the CPU to use the RAM or communicate with"
    },
    {
      "speaker": "Josh",
      "startTime": "289.324",
      "endTime": "295.13",
      "body": "storage and input and output devices. Most motherboards also include a number of controller"
    },
    {
      "speaker": "Josh",
      "startTime": "295.13",
      "endTime": "300.955",
      "body": "chips, collectively called the chipset. The chipset is like the traffic director on the board."
    },
    {
      "speaker": "Josh",
      "startTime": "301.237",
      "endTime": "309.252",
      "body": "It manages communication between the CPU, memory, and peripherals. In older PCs, you'll find two main"
    },
    {
      "speaker": "Josh",
      "startTime": "309.252",
      "endTime": "314.636",
      "body": "chips, nicknamed Northbridge and Southbridge, one focused on fast connection."
    },
    {
      "speaker": "Josh",
      "startTime": "314.636",
      "endTime": "321.927",
      "body": "ones like the CPU memory and graphics, the other on slower I.O. like disk drives. Modern"
    },
    {
      "speaker": "Josh",
      "startTime": "321.927",
      "endTime": "327.414",
      "body": "designs have consolidated these. Today's CPUs have the memory and often graphics controllers"
    },
    {
      "speaker": "Josh",
      "startTime": "327.955",
      "endTime": "334.144",
      "body": "built right into the processors, so the traditional north bridge is gone. The motherboard usually"
    },
    {
      "speaker": "Josh",
      "startTime": "334.144",
      "endTime": "340.453",
      "body": "has a single chipset chip, which on Intel systems is often called a PCH, which stands"
    },
    {
      "speaker": "Josh",
      "startTime": "340.453",
      "endTime": "347.723",
      "body": "for Platform Controller Hub, which handles things like USB ports, SATA drives, networking, and"
    },
    {
      "speaker": "Josh",
      "startTime": "347.723",
      "endTime": "355.033",
      "body": "other I.O. This evolution means data can move more directly and faster in many cases, but"
    },
    {
      "speaker": "Josh",
      "startTime": "355.033",
      "endTime": "362.283",
      "body": "the principle is the same. One crucial component on the motherboard is the BIOS or UEFI chip,"
    },
    {
      "speaker": "Josh",
      "startTime": "362.283",
      "endTime": "367.11",
      "body": "a small, non-volatile memory chip, that contains the firmware, and a small, non-volatile memory"
    },
    {
      "speaker": "Josh",
      "startTime": "367.11",
      "endTime": "371.816",
      "body": "which is low-level software, that kicks everything off when you power up the PC."
    },
    {
      "speaker": "Josh",
      "startTime": "372.678",
      "endTime": "378.626",
      "body": "When you turn on your computer, the code in the BIOS runs first. It checks what hardware is present,"
    },
    {
      "speaker": "Josh",
      "startTime": "378.946",
      "endTime": "384.374",
      "body": "doing a power-on self-test, makes sure things are in order, and then boots up the operating"
    },
    {
      "speaker": "Josh",
      "startTime": "384.374",
      "endTime": "390.863",
      "body": "system from your drive. Without this firmware, your CPU wouldn't know how to get started."
    },
    {
      "speaker": "Josh",
      "startTime": "391.684",
      "endTime": "397.733",
      "body": "The BIOS settings interface, which you might have seen, where you can change boot order or enable and"
    },
    {
      "speaker": "Josh",
      "startTime": "397.733",
      "endTime": "404.622",
      "body": "disable features, is stored on this chip on the motherboard. So in a sense, the motherboard is"
    },
    {
      "speaker": "Josh",
      "startTime": "404.622",
      "endTime": "410.991",
      "body": "not just some dumb backplane. It also houses this critical firmware and some specialty controllers."
    },
    {
      "speaker": "Josh",
      "startTime": "412.413",
      "endTime": "417.801",
      "body": "The concept of the motherboard evolved over time as computers shrank from room-sized monsters"
    },
    {
      "speaker": "Josh",
      "startTime": "417.801",
      "endTime": "419.583",
      "body": "to the PCs we know of."
    },
    {
      "speaker": "Josh",
      "startTime": "419.583",
      "endTime": "428.208",
      "body": "In the early days of computers, the 1940s to 1960s, there wasn't a single board that held the whole computer together."
    },
    {
      "speaker": "Josh",
      "startTime": "429.053",
      "endTime": "432.873",
      "body": "This started to change once the microprocessor was invented."
    },
    {
      "speaker": "Josh",
      "startTime": "433.617",
      "endTime": "442.382",
      "body": "In the mid-1970s, computers like the MITS Altair used a microprocessor and had a bunch of boards plugged into the backplane."
    },
    {
      "speaker": "Josh",
      "startTime": "442.945",
      "endTime": "453.038",
      "body": "But soon, engineers realized you could put the CPU and some support circuitry on one board, and then have expansion slots for additional capabilities."
    },
    {
      "speaker": "Josh",
      "startTime": "454.445",
      "endTime": "458.929",
      "body": "Throughout the late 80s and 90s, motherboards kept integrating more functions."
    },
    {
      "speaker": "Josh",
      "startTime": "459.552",
      "endTime": "465.04",
      "body": "Initially, to get sound or networking, you'd install a separate sound card or network card."
    },
    {
      "speaker": "Josh",
      "startTime": "465.563",
      "endTime": "472.057",
      "body": "But manufacturers realized it was cheaper, and users liked it, if more features were built on board."
    },
    {
      "speaker": "Josh",
      "startTime": "473.171",
      "endTime": "486.929",
      "body": "By the end of the 1990s, it was common for motherboards to include things like audio codecs, basic 3D video, modem or network adapters, and I.O. ports without needing separate cards."
    },
    {
      "speaker": "Josh",
      "startTime": "487.63",
      "endTime": "491.487",
      "body": "This evolution also went hand-in-hand with smaller computers."
    },
    {
      "speaker": "Josh",
      "startTime": "492.56",
      "endTime": "496.066",
      "body": "Laptops in the 1990s pushed integration further."
    },
    {
      "speaker": "Josh",
      "startTime": "497.304",
      "endTime": "505.286",
      "body": "You can't have room for many plug-in cards in a laptop, so the motherboard or logic board in a laptop contains nearly everything."
    },
    {
      "speaker": "Josh",
      "startTime": "506.462",
      "endTime": "511.206",
      "body": "Today, devices like smartphones and tablets take this to the extreme."
    },
    {
      "speaker": "Josh",
      "startTime": "512.113",
      "endTime": "513.887",
      "body": "Their motherboards are highly integrated."
    },
    {
      "speaker": "Josh",
      "startTime": "514.527",
      "endTime": "517.662",
      "body": "Every essential component is on one tiny board."
    },
    {
      "speaker": "Josh",
      "startTime": "517.662",
      "endTime": "523.107",
      "body": "This makes for sleek, compact devices, though at the cost of upgradability."
    },
    {
      "speaker": "Josh",
      "startTime": "524.097",
      "endTime": "525.644",
      "body": "In the desktop world..."
    },
    {
      "speaker": "Josh",
      "startTime": "524.531",
      "endTime": "528.53",
      "body": "we still have the modular motherboards for flexibility and power."
    },
    {
      "speaker": "Josh",
      "startTime": "530.206",
      "endTime": "534.205",
      "body": "Whether it's a gigantic backplane in a 1960s mainframe,"
    },
    {
      "speaker": "Josh",
      "startTime": "534.448",
      "endTime": "538.204",
      "body": "or a colorful RGB lit gaming motherboard in 2025,"
    },
    {
      "speaker": "Josh",
      "startTime": "538.79",
      "endTime": "540.668",
      "body": "the fundamental job is the same."
    },
    {
      "speaker": "Josh",
      "startTime": "541.396",
      "endTime": "545.98",
      "body": "Provide a hub for all components to communicate and share power."
    },
    {
      "speaker": "Josh",
      "startTime": "548.929",
      "endTime": "553.029",
      "body": "In the Shell is written, researched, and recorded by me,"
    },
    {
      "speaker": "Josh",
      "startTime": "553.635",
      "endTime": "555.393",
      "body": "the PCB podcaster."
    },
    {
      "speaker": "Josh",
      "startTime": "556.928",
      "endTime": "559.614",
      "body": "If you are listening in an app that lets you rate shows,"
    },
    {
      "speaker": "Josh",
      "startTime": "559.897",
      "endTime": "561.916",
      "body": "please take a minute to rate this one."
    },
    {
      "speaker": "Josh",
      "startTime": "562.765",
      "endTime": "564.724",
      "body": "I would truly appreciate it."
    },
    {
      "speaker": "Josh",
      "startTime": "566.501",
      "endTime": "569.006",
      "body": "And remember, call your motherboard."
    },
    {
      "speaker": "Josh",
      "startTime": "569.551",
      "endTime": "571.692",
      "body": "She worries when you don't stay connected."
    },
    {
      "speaker": "Josh",
      "startTime": "573.712",
      "endTime": "577.004",
      "body": "That's it. Take care, and I'll see you next time."
    },
    {
      "speaker": "Josh",
      "startTime": "577.004",
      "endTime": "581.956",
      "body": "You"
    }
  ]
}