@dsc @pluralistic Randomly interesting to me: HP was one of the first companies to do this sort of thing. There was a time, long ago, when you would purchase large HP-UX boxes (pre-Superdome) that would have hardware inside that was "unlicensed," and thus disabled. To use that "hardware feature," you'd have to pay a fee (and sometimes a rolling subscription!). They did the same with their software.

@sekka @dsc @pluralistic IBM were doing this in the 1960s. Possibly the 1950s. Mainframes would be upgraded to the “large memory” model by a service engineer coming out and *cutting a link on a board*. In exchange for a few $100k down and another $5k/month on the service contract.

@nickbarnes @sekka @dsc @pluralistic We called it the "magic screwdriver", and wasn't (if I recall correctly) just about memory, the MVS system 370s/380s could be purchased with different CPU speeds, but actually the CPU limit was managed in software which an IBM engineer could change if you "upgraded". There were even processes running on MVS called "SOAK".