1. A method for decomposing a data access request into a plurality of lower-level I/O tasks in a RAID system, said method comprising: representing components of said RAID system as a hierarchical set of objects; generating a parent I/O task from a first object in said hierarchical set in response to said data access request; generating a child I/O task from a second object in said hierarchical set to implement at least a portion of said parent I/O task; and scheduling for execution said child I/O task in response to an occurrence of a first event such that execution of said child I/O task is not conditional on execution of said parent I/O task.