I had a home hacked 1TB+ server, using 5.25in 23GB 8lb monster drives salvaged from a long life as a TV video bank (long, long ago, when dinosaurs walked the earth). There was 60+ actual spindles as i recall.
The drive array was powered by 6x, 400W ATX server supplies with my own wiring harness. This was enough to keep them running but they had to be sequenced carefully to keep from overdrawing the power supplies.
This was all on an UltraSPARC 6k so there was plenty of support for that; bringing up the system always sounded like multiple jet takeoffs tho. Took 15min. When the rack of 10k RPM "quick cache" disks spun up it was like a chorus of the whines of the damned.
I had a MicroVAX in my bedroom which booted with a tick-tack-tick-tack going faster and faster culminating in a crescendo where it sounded like the discs synced up or something.
I'd then login to a prompt and type DIR before I turned it off again. I just pulled the power switch, I had no idea how to do a proper shutdown.
This was a feature on SCSI disk controllers. I remember one controller that had dip switches to set the spin up sequence number, and then you would configure the controller to wait for all the drives to be spinning before it tried to bring the array online.
I'm going from memory here but each Ultra 320 SCSI HDD had a startup current of almost 2 Amps so if you had a disk shelf with 24 drives and stack a few shelves in each rack you could do some serious power damage if you didn't plan the startup sequence right.
On a per-machine basis, many server motherboards have out-of-the-box BIOS support for this feature. At least they used to. It's been a long time since I've built a server and mechanical hard drives are less common than they used to be.
There was some home computer - either an original Apple II or a Commodore PET, I don't remember - where if you splurged for the fancy second disk drive, the computer could be destroyed by a rogue program spinning up both drives at once. And since every program ran at the same protection level as the OS (because there were none), it was either two MOVs or two POKEs to the hardware registers to make it happen.
The drive array was powered by 6x, 400W ATX server supplies with my own wiring harness. This was enough to keep them running but they had to be sequenced carefully to keep from overdrawing the power supplies.
This was all on an UltraSPARC 6k so there was plenty of support for that; bringing up the system always sounded like multiple jet takeoffs tho. Took 15min. When the rack of 10k RPM "quick cache" disks spun up it was like a chorus of the whines of the damned.