Mechanisms are provided, in a storage system controller of a storage system, for writing data to a storage medium. The storage system controller receives a write request to write a block of data to the storage medium. The write request does not specify a location on the storage medium to which to write the block of data. The storage system controller determines a current position of a write mechanism of the storage system relative to the storage medium and determines a location on the storage medium to write the block of data based on the current position of the write mechanism. The storage system controller sends a notification to a host system identifying the location of the block of data on the storage medium as determined by the storage system controller. The writing mechanism writes the block of data to the determined location on the storage medium.