The Forgotten Tale of Cartrivision's 1972 VCR
harrymcc writes: In 1972 -- years before Betamax and VHS -- a Silicon Valley startup called Cartrivision started selling VCRs built into color TVs. They offered movies for sale and rent -- everything from blockbusters to porn -- using an analog form of DRM, and also let you record broadcast TV. There was also an optional video camera. And it was a spectacular flop. Over at Fast Company, Ross Rubin tells the fascinating story of this ambitious failure.
using an analog form of DRM
So, that'd be "RM", then.
In case you're wondering, it was simply that only the rental store could rewind rental tapes (cartridges).
Not so much rights management as blanket functionality removal.
systemd is Roko's Basilisk.