*
* Different modes can be active at a time, but only
* one can be set at array creation. Others can be added later.
- * A mode can be one-shot or recurrent with the recurrance being
+ * A mode can be one-shot or recurrent with the recurrence being
* once in every N requests.
* The bottom 5 bits of the "layout" indicate the mode. The
* remainder indicate a period, or 0 for one-shot.