You must initialize the data item name. If you plan to use the user-defined data field and the parity bits, you must also initialize these fields. Otherwise, you can specify zeros for the user-defined data field and parity bits. You must also indicate whether the system marks the data item as changed. Indicating the changed status of a data item depends on whether you successfully write the data item to permanent storage.

During normal cast-out processing, you write changed data for each data item to permanent storage. For a successful write operation, issue the request to release the lock and ensure that the value of the change indicator informs the system to leave the change state as is. As long as no other user has updated the data item while you held the lock, the system considers the data item as unchanged and the storage resources are eligible for reclaim. For an unsuccessful write operation to permanent storage, issue the request to release the lock and set the change indicator to mark the data item as changed. By marking the data item as changed, the system cannot reclaim data item resources for other requests so that you can preserve the changes until you are able to write the data item to permanent storage.