AGlossary
264 U929-J-Z125-9-76
act-key
(actual key) Actual address of a page, consisting of realm number and page
number.
act-key-0 page
First page of a real m; contains general information on the realm such as
– when the realm was created,
– when the realm was last updated,
–internal version number of the realm,
–system break information
– if applicable, warm start information.
act-key-N page
Characteristic page of a real m, with the highest page number.
Copy of the act-key-0 page.
address, physical
See act-key or PPP.
administrator task
Task of the independent DBH; The database administrator can control execution of
the independent DBH via this task.
AFIM
See after-image.
after-image
Modified portion of a page after its content has been u pdated.
The DBH writes after-images to the RLOG file as well as the ALOG file.
after-image, ALOG file
The after-images are written to the ALOG file when the ALOG buffer is full. The
purpose of the after-images in the ALOG file is to secure the dat a contained in
the database and thus they must be maintained for a long period of time. They
are used to reconstruct an original database or update a shadow database.
after-image, RLOG file
After-images are logged in the RLOG file before the updates are applied to the
database. The after-images held in the RLOG file are required for warm start only.
They are thus periodically overwritten.
ALOG file
File for securing the data contained in the database in the long term; see after-
image.