You can use the WRITE_ONCE option to change a storage area
    containing stable segmented string data to a format that can
    be stored on a write-once, read-many (WORM) optical disk. A WORM
    optical disk offers a relatively inexpensive way of storing large
    amounts of data for read-only access compared to other storage
    media.

    The following restrictions apply to the WRITE_ONCE option:

    o  Note that you cannot write data other than segmented strings
       to a write-once storage area. Oracle Rdb issues an error message
       if you try to create a storage map that stores data other than
       segmented strings in a write-once storage area. Storage maps
       for non-segmented-string data must be removed before you can
       alter a storage area to WRITE_ONCE.

    o  When you create a storage area on WORM media, you must specify
       that the snapshot area remains on read/write media: do not
       give a snapshot file the WRITE_ONCE attribute.

    o  If you specify the WRITE_ONCE option when storing a segmented
       string, database keys are not compressed. For more information
       on database key compression, see the Oracle Rdb Guide to Database
       Maintenance.

    o  Write-once storage areas do not use SPAM pages to look for
       storage space, but to assist moving data back to non-WORM
       media in which SPAM pages must be built again, space is still
       allocated for them. Since SPAM pages are essential in uniform
       areas, Write-once storage areas cannot be of uniform format
       and therefore are required to be of mixed format.

    o  You can use the PAGE SIZE IS clause of CREATE STORAGE AREA to
       change the default page size for a storage area. To optimize
       storage, always specify an even number of blocks per page.

    o  Rdb does not support magnetic media for storing write-once
       storage areas.

    o  After you move a storage area to or from a WORM device,
       Do a full and complete backup of your database with the
       RMU/BACKUP command and start a new after-image journaling
       file. For more information on backup and recovery procedures
       with write-once storage areas, see the Oracle Rdb Guide to
       Database Maintenance.