this is a channel that covers a lot of old computer hardware (usually like 1970s old), but recently they've been working on a resurrecting a Bendix G-15, a fully vacuum-tube digital computer from 1956
this video covers the first time they give it actual juice, which required running a dedicated power connector to the room it's in because not surprisingly you can't get 60 amps off a standard wall outlet, and once it's partially powered up (on AC but not yet DC power) they check to see if the rotating drum memory system still has the clock tracks on it
if like most of us, you've only ever used modern (80s and newer) computers, then those systems have all generated the system clock from a timing crystal of some sort, in the megahertz to gigahertz ranges. that crystal vibrates at a fixed and consistent rate, and all the components in the system are timed from that vibration to keep everything in sync
the ancient beast in this video uses a magnetic drum, spun by electric motor, not only for the RAM in the system but also for the clock. there is a permanent factory-written memory track on the drum that is read on every rotation to generate the clock, so the speed of the system is directly tied to the rotational speed of the drum's motor
this is fascinating to me because it suggests a whole range of fictional, fantastical computing technologies where overclocking your equipment is a much more analog and physical process. a building-sized steam-driven calculation engine with a Scottish engineer, asked to push the system's speed past safe limits to crack the Prussian codes in time for tomorrow's military action. a robot with a head full of micro-drums who can make himself think faster if he stays very still to keep them from falling out of alignment at high RPM. computing hardware designed by elves where the system clock is dependent on the current speed of the wind, the clock drum driven by a windmill for purely aesthetic and philosophical reasons
and also, just the fact that we replaced a wheel with a singing crystal to tell our computers how fast to go
