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. You should
       specify an even number of blocks per page. The smallest amount
       of space used in a write operation to WORM media is 1024 bytes
       (2 blocks). Therefore, by specifying an even number of blocks
       per page, you minimize the space wasted when writing segmented
       strings to WORM media.

    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.