response: I am not sure about how common they are today, but I do know that thoses dics were used as the primary medium for the reproduction of music until the ending of the 20th century
original_response: Not at all, they were both used to produce music until the late 20th century.
history: Are you familiar with phonograph records? I've never heard of them. Yes, I have heard of them. They are a medium to store analog sound which is known as Gramophone in British english, did you know about that ? I had no idea. What else do you know about them? Well, I also know that the grooves start close to the periphery of the disk and only ends close to the center Very interesting. Do you know what they are made of ? I do know that. Starting in the 50's, the commom material used became polyvinyl chloride Nice to know that. Are they still common today ?
knowledge: The phonograph disc record was the primary medium used for music reproduction until late in the 20th century.