Glossary

Archive

Set of n data point elements that are, by definition, recorded together. An archive is determined by the members of the archive (DPE1...DPEn), as well as by the (shared) parameters for saving them (file change, swap-out cycles, deletion cycles).

The individual DPEs within an archive can be of different data types. With regard to effective management, the following points should be considered when defining archives: dynamics (about the same change rates of all DPEs in an archive), logical affiliation, necessary availability in the system.

Archive record

Individual data record of an archive that contains the historical data of all n DPEs for the time period between two archive record changes. The maximum size of an archive record is defined in the archive definition (archive parameters). An archive record generally always occupies the same place on the hard disk, irrespective of the "filling level". The physical size of the archive file is adapted to the actual required space only after "archive compression".

Archive file

File containing all the data of an archive record. Either on the hard disk in the current archive directory (archive record available online) or on a backup or swap-out medium (offline archive record).

Online archive

Total historic data of an archive that can be addressed during runtime (all archive records).

Offline archive

One or more archive records (archive files) that are not located in the current archive directory of a WinCC OA project. These are generally referred to as "swapped-out" archive records or "swapped-out" history.

Archive record change

Process where an old archive record is closed and a new one is opened. The closed archive record can then be copied as required without any precautions.

Backup

Backup of a WinCC OA project together with the historical data of the online archive for restore purposes after a hardware or software error.

Archive backup

Archive backup copies archive records so that they can be reused later (after deletion or in case of data loss). The archive records are backed up on a removable medium (removable disks, tapes). During the backup process, write actions are buffered to the appropriate archive records to maintain a consistent data image (online backup).

Correction values

Value that is entered in the values history before the last value. The correction value is mirrored in the offline value and can also exist concurrently with an already existing Original value (whose offline value then replaces the correction value).

Archive cycle

Describes the periodical sequence of file changes for a particular archive ("weekly", "daily"). Without any further details, the archive cycle is always the currently valid term for an online archive.

Swap-out cycle

Describes the frequency with which the online archive is removed from the system and saved in a different place (DAT, CD,...). Example: Each month, all the archive records that are online in the system and are older than one month are swapped out.

Deletion cycle

Describes the frequency with which the online archives (archive records) are removed from the system and deleted from the hard disk. Make sure that you have swapped out or backed up the archives before the deletion.