I want to stay out of this discussion, because it's all been said before, but I wanted to point out, with respect to the argument regarding whether the arm pod moves due to stylus drag, that the mass of the arm pod, no matter how great, is not the major determinant of its being moved by stylus drag. Rather, the major determinant is the coefficient of friction between the base of the arm pod and the shelf. (Think, if the shelf were made of ice and the arm pod was of the mass of a curling stone [38 to 44lbs, according to Wiki], the pod would move easily.) I am not pointing this out in order to take sides in the discussion. I really don't care whether the arm pod moves or not, because I don't use an arm pod.
Second, I must agree with Richard, the Timeline says nothing about whether the arm pod moves. It only says that IF the arm pod moves, the mechanics of the tt (motor/servo/mass of the platter) are such that the Timeline read-out is unaffected. For all we know based only on the Timeline, the arm pod could be swinging around the whole circumference of the platter as if tethered to the platter, and the Timeline won't tell us this is happening unless the motor/servo/platter is not up to overcoming the resulting drag (call it "arm pod drag"). This is as obvious to me as is the opposite view to Halcro.
Second, I must agree with Richard, the Timeline says nothing about whether the arm pod moves. It only says that IF the arm pod moves, the mechanics of the tt (motor/servo/mass of the platter) are such that the Timeline read-out is unaffected. For all we know based only on the Timeline, the arm pod could be swinging around the whole circumference of the platter as if tethered to the platter, and the Timeline won't tell us this is happening unless the motor/servo/platter is not up to overcoming the resulting drag (call it "arm pod drag"). This is as obvious to me as is the opposite view to Halcro.