Digital Event Services (DES) enables an administrator to set a delivery mode per event type. The delivery mode setting governs the quality of service if the DES runtime stops responding and becomes unavailable.

Digital events are stored in-memory or on-disk until their delivery is acknowledged. To ensure that at least one copy of an event is delivered, administrators can define the event type delivery mode as persistent. This means that the events of an event type are stored on-disk. If the runtime where DES is embedded becomes unavailable, the events are resent the next time the runtime starts.

If the delivery mode for an event type is non-persistent, events are stored in-memory. If the runtime where DES is embedded becomes unavailable events are not resent. Administrators can define on-disk and in-memory capacity globally and per event type.