alt Hacker NewsRX-01 DEC / IBM 3740 compatible was 77 tracks, single-sided, 128 bytes per sector and 26 sectors per track. Total 256,256 bytes. FM Modulation. 360 RPM. Disk to drive buffer: 4 µsec per data bit. Track-to-Track Seek: 6 ms. Head Settle Time: 25 ms. Average Access: Approximately 262 ms. 8" diameter diskette
One of these was used to load the microcode into the VAX-11/780 upon boot.
My old PDP11/73 (now in a museum) had two RX02, never had an RX01. Surprisingly fast! It also had two RL02s and a couple of RD54s in.
Building an RT11 system disk onto an RL02 off another RL02 made the downstairs neighbours complain quite a lot, even though the floor slab in my flat was about 40cm thick concrete. They didn't muck about with these 1960s tower blocks but it was no match for a pair of pint glass sized head actuators and a pair of washing machine motors.