titles_dbhdr

                          DBHDR      Database Header
                          ==========================
 
    Contact:  N. West, Oxford.
 
    Revision History:-
    ================
 
    1.03  N. West     First version with revision history.
    2.03  N. West     Add PRINT_FLAG.
    2.05  N. West     Document tidy up.
    3.00  N. West     Complete rewrite for database access and dynamic titles
                      management.  Rename _CONNECT_ID -> _MANAGED_ID.
          R. Komar    Add two mnemonics for checksum words (17 and 18).
                      Remove the checksum word mnemonics.


 
Titles Files
------------
 
* (all titles have headers)
 
 
Verification
------------
 
 
Description
-----------
 
    All banks stored in the Database, and this includes "titles" banks start
with a fixed length Database Header.  See Management of Titles in the User and
Programmer Manuals for further discussion of "titles".
 
Reference Links
---------------
 
    n/a
 
Structural Links
----------------
 
    n/a
 
Status Bits
-----------
 
Note: Any status bit parameters are defined to work with bit functions such as
      IAND and BTEST.
 
Data Words
----------
 
     All data words are integer.
 
 
        KDBHD...
 
        _HSZ               Size of header  (not stored in header, see titles_dbhdr.inc)
 
 
    1   _START_DATE        Intrinsic start date in form YYYYMMDD. See Note 2.
    2   _START_TIME        Intrinsic start time in form HHMMSSCC.
    3   _END_DATE          Intrinsic end date in form YYYYMMDD.
    4   _END_TIME          Intrinsic end time in form HHMMSSCC.
    5   _DATA_TYPE         Data type.See Note 3
    6   _TASK_TYPE         Task number.  Currently set to zero.  See Note 4
    7   _FORMAT_NUM        Format number. Currently set to zero.  See Note 5
    8   _CREATION_DATE     Date at which bank was created in form YYYYMMDD.
    9   _CREATION_TIME     Time at which bank was created in form HHMMSSCC.
    10  _SOURCE_ID         To be defined.
    11  _EFF_START_DATE    Effective start date in form YYYYMMDD. See Note 6
    12  _EFF_START_TIME    Effective start time in form HHMMSSCC.
    13  _EFF_END_DATE      Effective end date in form YYYYMMDD.
    14  _EFF_END_TIME      Effective end time in form HHMMSSCC.
    15  _ENTRY_DATE        Date at which bank was entered into the Master
                           database in form YYYYMMDD.
    16  _ENTRY_TIME        Time at which bank was entered into the Master
                           database in form HHMMSSCC.
 
    The remaining words, although part of the header, are updated by the
    Management of Titles system (MTT); the value as stored in the database is
    not significant.
 
    24  _SOURCE            Source of the bank for current job:-
                               = 0 From database, =2 from titles file.
    25  _MODIFIED          Number of words modified by SET BANK commands.
    26  _MANAGED_ID        Connection Id.  See Note 7
    27  _MBT_PTR           Link to the appropriate entry in MTT's internal
                           Managed Bank Table.  If = 0 the bank is "floating"
                           i.e. not currently in use by MTT.
    30  _PRINT_FLAG        Print flag.  Where appropriate, Software Units can
                           use this word to control their print level.
                           Convention:-
                             -1    None.
                              0    Normal production level.
                              >1   More (possibly debug) output.
 
Notes
-----

1)  To access the header part of a bank use the standard bank link (Lxxxx)
    rather than the data link (LDxxxx).  For example:-
 
     ICONS(LNTPC + KDBHD_PRINT_FLAG)
 
    is the print flag word in the header of the NTPC bank whereas:-
 
       ICONS(LDNTPC + i)
 
    is the ith. data word of the NTPC.
 
 
 
2)  The intrinsic validity range of a bank is the validity range a bank would
    have if placed in an otherwise empty database.
 
 
3)  When attempting to match data types between database banks and the current
    event, MTT first attempts to find an exact match, but if that fails, will
    look for a more general one. The sequence is:-
 
    1)  An exact match.
    2)  For Monte Carlo data only, the equivalent real data type (e.g. for
        data type 21 (MC SNO) match 11 (Real SNO).
    3)  Data type 0 (universal).
 
    This represents a strict priority; higher entries in the list always take
    precedence over lower ones.
 
 
4)  Task types are currently set to zero.  They may be used in the future in a
    single processor needs to be optimised in different ways to do different
    tasks
 
 
5)  Format Numbers are currently set to zero.  They will be incremented only if
    a bank undergoes a non-backward compatible change.
 
 
6)  The effective validity range of a bank is the validity range a bank has in
    the database as a result of neighbouring and overlaying banks which trim
    its intrinsic validity.
 
 
7)  Each time a bank comes under MTT control, or is updated by MTT to honour a
    SET BANK command, it is given a new, unique Managed id.  As this id will
    change each time the bank contents change, it can be used by the requesting
    SU to detect changes in its titles.  Note:  A change in a bank's validity,
    due to the introduction of neighbouring banks, does not cause the id to
    change.