1. In error situations that do not involve storage medium failures, ADABAS automatically restores the last consistent state of the database on restart. This means that all effects of committed transactions are preserved, while the effects of transactions open at the time of error occurrence are cancelled.
2. Storage medium failures require the loading of a previously backed up version of the database. They may also require the loading of several incremental data backups (see Backup / Save / Updated Pages menu function in the CONTROL manual) to restore the database to a state upon which the last log versions may be re-applied. When these actions are concluded, the last consistent database state has been restored.
3. ADABAS does not support the exchange of storage media. Instead, individual tables can be explicitly unloaded. This function is supported by the ADABAS component LOAD.
4. The ADABAS component CONTROL (see the CONTROL manual) which serves to perform the above-mentioned backup and recovery operations of the database can only be used by the CONTROLUSER. CONTROL can usually only be used once for each SERVERDB at any given time, parallel to normal database operation.