Abstract: On existing DVD and CD players a control loop is required for the adaptation and timing recovery. For Two-Dimensional Optical Storage such a control loop has drawbacks because PRML detection in the form of a stripe-wise Viterbi detector is used. Such a detector introduces an increasing detection delay when going from the outer rows towards the center of the broad spiral. A feedback loop is arranged to determining an error signal from a first area of the data block where the first area is that area where the error signal can be determined within the shortest period of time. This reduces the duration of the detection step and thus increases the stability of the control loop.