77 lines
3.4 KiB
HTML
77 lines
3.4 KiB
HTML
<!doctype html>
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<html lang="en">
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<head>
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<title>What is Magnetic-core memory?</title>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1" />
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<meta name="description" content="HTML & CSS Course Examples.">
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<meta name="author" content="Sebastian Wendel" />
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<meta name="created" content="2024-02-09T14:14:22.450262740" />
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<meta property="og:title" content="What is Magnetic-core memory?" />
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</head>
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<main>
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<article class="article">
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<h1 class="article__headline">
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What is Magnetic-core <span class="p-uppercase">memory?</span>
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</h1>
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<hr class="p-separator" />
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<p class="p-text-style">Core memory uses
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<a href="https://en.wikipedia.org/wiki/Toroid">toroids</a>
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(rings) of a
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<a href="https://en.wikipedia.org/wiki/Hard_magnetic_material">hard
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magnetic material</a>
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(usually a
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<a href="https://en.wikipedia.org/wiki/Ferrite_(magnet)#Semi-hard_ferrites">semi-hard
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ferrite</a>). Each core stores one
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<a href="https://en.wikipedia.org/wiki/Bit">bit</a>
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of information. Two or more wires pass through each core, forming an
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X-Y array of cores. When an electrical current above a certain
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threshold is applied to the wires, the core will become magnetized.
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The core to be written is selected by powering one X and one Y wire
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to half of the required power, such that only the single core at the
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intersection is written. Depending on the direction of the currents,
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the core will pick up a clockwise or counterclockwise magnetic field,
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storing a 1 or 0.
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This writing process also causes electricity to be
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<a href="https://en.wikipedia.org/wiki/Electromagnetic_induction">induced</a>
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into nearby wires. If the new pulse being applied in the X-Y wires is
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the same as the last applied to that core, the existing field will do
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nothing, and no induction will result. If the new pulse is in the
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opposite direction, a pulse will be generated. This is normally
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picked up in a separate "sense" wire, allowing the system
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to know whether that core held a 1 or 0. As this readout process
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requires the core to be written, this process is known as destructive
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readout, and requires additional circuitry to reset the core to
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its original value if the process flipped it.
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</p>
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<figure class="figure">
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<img class="" src="./img/IMG_20240205_00.webp"
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alt="A Core memory Module showing the detailed structure of ferrite cores and copper wires.">
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</figure>
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<footer class="footer">
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<p>
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<small class="footer_small">
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Source: <a href="https://en.wikipedia.org/wiki/Magnetic-core_memory">Wikipedia:
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Magnetic-Core-Memory</a>
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</small>
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</p>
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</footer>
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</article>
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</main>
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</body>
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</html> |