The basic idea is that users can either choose to leverage the full capacity of the SSD or reduce the size and reserve some of the memory cells as a safety net when other memory cells fail. In effect, less capacity can provide a longer drive life.
IBM envisions that users can configure the desired drive life in combination with a minimum storage capacity, which will be done via the firmware of the SSD: "Based on the user configuration and the utilization, a portion of the SSD memory devices is allocated as available memory, and another portion of the SSD memory devices is reserved as overprovisioned memory, to be used as fallback when available memory devices reach their PE wear out threshold," the patent states.
During usage, a drive could be using self-monitoring tools and dynamically adjust storage space, depending on the actual use of the drive. "The proportion of available memory to overprovisioned memory may be adjusted if the utilization changes; as the SSD utilization changes, the controller may allocate or de-allocate available memory to meet the SSD drive life configuration. The SSD drive life is therefore predictable and adjustable."
Such features are extremely helpful in corporate environments, especially in areas where SSDs are used in database applications.