Abstract: Apparatuses and methods for controlling the quality of writing an optical storage medium in an optical storage system having an accessing logic for steering data to be written onto or read from the optical storage medium. The apparatus contains a halting controller, an evaluation device, a recording tangential velocity (RTV) adjusting device, and a starting controller. The halting controller requests the accessing logic to halt a write procedure at a stopping point. The evaluation device evaluates the writing quality of a portion of the data recorded onto the optical storage medium to generate an evaluation result. The RTV adjusting device requests the accessing logic to adjust the RTV of the optical storage medium if the evaluation result does not satisfy predetermined criteria. Finally, the starting controller requests the accessing logic to restart the write procedure to continue writing data onto the optical storage medium.