Before the CD came out, you could record your own digital audio - on video tape. Have a look at a HiFi unicorn, the Technics SV-P100 - the first integrated digital audio tape recorder. In this video you'll get a demo and hear about the history of PCM recording onto tape. This all took place years before the introduction of DAT in 1987 - (Digital Audio Tape). If you’re interested, here's a video all about DAT: https://youtu.be/F4K1QKKPX_g