I'm not sure what they used for 286 era machines for hard drives but I suspect it was plain old IDE, which you could probably connect directly to a more modern machine. I was still in Amiga land until the 486.
Incidentally, the only 286 I ever owned was actually a board that I got for the Amiga that plugged into the CPU socket with the unholy alliance of a 286 + Motorola CPU. You could use them at the same time to run PC stuff and Amiga stuff. It was a hack of hacks. But it worked!
> I'm not sure what they used for 286 era machines for hard drives but I suspect it was plain old IDE,
It was not. It was the precursor to IDE, where the drive was just a disk and head actuator, and all the magnetic signal decoding electronics were onboard an ISA card plugged into an ISA slot.
What was initially offered as the first "IDE" was taking the analog electronics on that ISA card and moving them onboard the drive and just "extending" (essentially) the ISA bus out to the drive.
Incidentally, the only 286 I ever owned was actually a board that I got for the Amiga that plugged into the CPU socket with the unholy alliance of a 286 + Motorola CPU. You could use them at the same time to run PC stuff and Amiga stuff. It was a hack of hacks. But it worked!