Sony discussed on TechStuff
To the future it factors into the plot in the original back to the future. Anyway, by the mid nineteen eighty s Sony was trying to replicate the success of the walkman with a CD player. And the result was the disc, man. D fifty the world's first portable CD player. And while the d fifty had some shortcomings, it truly was an amazing technological achievement. See the D fifty was small, and it was about the size of maybe five or six CD cases stacked on top of each other. So that meant all the circuitry and all the components of a full-size CD player needed to be shrunk down to fit this tiny form factor. And this was just a couple of years after the full sized version of a CD player had come out. So it's hard to explain exactly how challenging this was. But here's an example, the optical path for the laser was a huge obstacle to work around the size, constraints Sony engineers had to figure out how to fold the optical path to make enough space for it to have the laser position in the right way for the disk on top of that the engineers had to custom build all the circuits. For the deficiency to both fit inside this small case and not immediately drained the batteries of all their juice, even so the d fifty was pretty power thirsty gadget as walkman central a fund website has explained you could buy a battery holder that would plug into the defeat to supply the electricity would.