system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How were CDs and DVDs professionally made? What computers, software, and printers are used?
gpt
They use a clean room and production line.   
Sound typically came from digital audio tape (in the '90s) and was then transferred on a glass disc called a master, using lasers. This master was then plated with metal to create a stamper. This entire process was relatively slow and took place in a clean room.  
  
The stamper was used to mould large amounts of cds (which are made out of plastic) on a production line. This is a quick process that only takes a few seconds per cd. Afterwards reflective material was dampened on the disc and the disc was coated with lacquer for protection.    
  
It is a different process compared to burning  cd-recordables, as recordable discs have a layer with organic dye that can be burned using a laser. This also gives cdrs their distinctive color.