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*    EZDB 5.6 Tech Note CDI05T01                         July 2010 *            
*                                                                  *            
*    KEYWORDS   : EZ-DB R17 SYSTRK CHANGE TRACKING IMAGE COALLOC   *            
*                                                                  *            
*    COREQS     : CGI05014                                         *            
*                                                                  *            
*    DESCRIPTION: IDMS R17 introduced a new optional facility to   *            
*                 manage Change Tracking for the CV. Change        *            
*                 Tracking is not fully compatible with some EZ-DB *            
*                 components and there are certain limitations to  *            
*                 be aware of.                                     *            
*                                                                  *            
*    TAPES      : EZDB CI0502                                      *            
*                 CA-IDMS RELEASES 17.0                            *            
*                                                                  *            
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*                                                                  *            
*    DETAILS:                                                      *            
*                                                                  *            
*    Change Tracking records the files and datasets in use by the  *            
*    CV, including any dynamic changes made while CV is active.    *            
*    This allows any subsequent warmstart to have accurate details *            
*    of files/datasets in use at the time of the abend.            *            
*                                                                  *            
*    The Change Tracking details are kept in one or more SYSTRK    *            
*    datasets defined to CV. At startup a copy of the DMCL is      *            
*    written to the SYSTRK datasets. IDMS then intercepts certain  *            
*    DCMT commands affecting files/datasets and writes details of  *            
*    any changes to SYSTRK.                                        *            
*                                                                  *            
*    Two of the EZ-DB components are affected by Change Tracking:  *            
*                                                                  *            
*      - EZ-Allocate                                               *            
*      - EZ-Image                                                  *            
*                                                                  *            
*    EZ-Allocate                                                   *            
*    -----------                                                   *            
*                                                                  *            
*    EZ-Allocate will still function as normal when Change         *            
*    Tracking is active. File allocations defined via a COALLOC    *            
*    file and the use of the COALLOC8 task will operate normally,  *            
*    BUT file/dataset details set/updated via EZ-Allocate are NOT  *            
*    written to the SYSTRK files. Any subsequent warmstart will    *            
*    not be aware of files/datasets that were set/updated by       *            
*    EZ-Allocate dynamic allocation.                               *            
*                                                                  *            
*    This is because IDMS only monitors certain DCMT commands and  *            
*    is totally unaware of changes made directly by EZ-Allocate,   *            
*    so such changes will not be reflected in the SYSTRK files.    *            
*                                                                  *            
*    Recommendation: If Change Tracking is critical to your CV     *            
*    then EZ-Allocate (dynamic allocation) should not be used.     *            
*    If it is used, then you need to be aware that the Change      *            
*    Tracking warmstart facilities may be compromised.             *            
*                                                                  *            
*    EZ-Image                                                      *            
*    --------                                                      *            
*                                                                  *            
*    EZ-Image modifes the runtime DMCL to dynamically add the      *            
*    Image segments. This modified DMCL is not compatible with     *            
*    Change Tracking (SYSTRK).                                     *            
*                                                                  *            
*    If EZ-Image is active when CV starts and Change Tracking is   *            
*    enabled, then CV will abend.                                  *            
*                                                                  *            
*    Optional PTF CGI05.014 will check for Change Tracking when    *            
*    EZ-Image is initializing. If Change Tracking is active, then  *            
*    appropriate messages are output and EZ-Image is disabled.     *            
*    CV will then continue to start as normal.                     *            
*                                                                  *            
*    Recommendation: Do not attempt to enable Change Tracking on   *            
*    a CV where EZ-Image is required, as they will not function    *            
*    together.                                                     *            
*                                                                  *            
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