One algorithm for this task deals with potential race conditions by inserting low-level “reference barrier” code on reads and writes that allow it to safely move data. That algorithm for this task is named Shenandoah. “Eden space” is one term for the first level of a hierarchy used by algorithms for this task that account for the empirically-justified generational hypothesis. Cheney’s algorithm for this task was the first to copy between “to-space” and “from-space,” in an example of (*) tri-color approaches to this task. Weak references can prevent cycles that hinder completing this task. Early algorithms for this task “stop the world” periodically (10[1])to perform mark-and-sweep passes, leading to unpredictable large pauses in execution. Reference counting is an alternative to tracing methods for this task. For 10 points, name this task of cleaning up memory that holds unreachable objects. ■END■