Those old WD 20MB XT-IDE disks use a stepper motor + worm screw for head movement, so the beep comes from that. (it's like a 3.5" floppy drive, but with a fixed disk :-)
Try and see if the head follows the worm, it might be that there's some gunk there that stops it from moving accurately enough.
The boot disk is for that very drive, isn't it?
Don't try to connect the XT-IDE drive to an AT-IDE controller. Bad things will happen. Also, don't try AT-IDE drives in the A590's XT bus.
The A590 is a good controller, by the way.. The SCSI side (which C= didn't use per default!) is 1.5MB/s on a 68000 if you have fast ram on board the controller. It also does DMA. Pity C= crippled 'em with those crap XT drives. :-P
