• Echo Dot@feddit.uk
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    4 days ago

    Well you etch pits you don’t actually use numbers. Also it’s not a spiral, it’s not a record player it’s not been read by physical stylus so you don’t need a guide, they’re just concentric circles.

    You start the disc off as a zero, then whenever you need to transition to a one you etch a pit, then it will continue to read that as one until you etch another pit and flip back to zero. So the sequence 0111001 would be etched as _.__.__.

    Discs can also be overwritten, and used multiple times, you just wipe the entire top layer off and start again on the layer below, only really cheap CDs were single use.

    As for the future there are already experimental crystal storage solutions (made out of artificial diamond so it would be essentially indestructible) which really are single use, but they can store hundreds of petabytes of data so you would probably just treat them as if they were rewritable. There’s also DNA storage but the equipment to save and read the data is nowhere near commercially viable yet.

    • Frezik@lemmy.blahaj.zone
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      4 days ago

      The pits just represent numbers. A 1-bit memory cell typically stores high or low voltage. The numbers 0 and 1 only exist as a platonic ideal, and there are many ways to represent them in the real world.

    • SCmSTR@lemmy.blahaj.zone
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      4 days ago

      Ngl, i didn’t know it was concentric circles. I always thought it was a spiral like a vinyl record.

      Also the encode is pretty neat, I didn’t know that.

      I DID know about RWs being rewritable, and you could sort of brute force some supposedly single write discs.

      To be clear, I wrote that to be as simple as possible like if a person read it who really didn’t have any idea, they could have a relatively quick understanding in plain terms. Guess even I learned something today!