2. PLANNING › 2.1 Software Dependencies

2.1 Software Dependencies

VCC is designed to have few dependencies on the operating
system.  However, in order for VCC to operate correctly, some
dependencies on the operating system do exist and you should
be aware of them in case there is a conflict.

The VCC operating system dependencies are the following:

    o  OS/390 UCB control block. VCC uses the UCBSCAN service
       to obtain information on all the online DASD volumes.
       All UCBs are pinned so that any dynamically added
       devices are not deleted during VCC execution. Once
       processing of the UCB is completed the UCB is
       unpinned.

    o  The CAXWA control block chain for all open VSAM/ICF
       catalog. If a master catalog name (VSAM or ICF) and
       its volume serial are not supplied, this information
       is obtained by scanning the CAXWA control block chain.

    o  SVC 26 (LOCATE) is used to locate VSAM information.
       This SVC is used to allocate and open catalogs (VSAM
       or ICF) before they are opened as data sets. VCC
       depends upon the format of the SVC 26 parameter list.

    o  The STEPCAT flag is turned on in the PCCB that is
       created when a catalog is opened as a catalog through
       the use of SVC 26.  This is done so that serialization
       problems do not arise when multiple subtasks attempt
       to open and read catalogs as data sets.  After a
       catalog has been processed by VCC, this bit is reset
       (turned off).  This eliminates the requirement to have
       STEPCATs if VSAM catalogs are being processed as data
       sets.

    o  VCC optionally records to SMF using the SMFWTM macro.

    o  To collect data regarding data sets managed by DFHSM,
       the ARCUTIL interface program is required.  This
       program was delivered by IBM in Version 2.5 of DFHSM
       and certain enabling PTFs support this function at
       Version 2.4 of DFHSM.  Check with IBM Customer Support
       for the PTF numbers required at the 2.4 level of
       DFHSM.  This ARCUTIL interface is the same technique
       used by the DCOLLECT function of IDCAMS available at
       DFP Version 3.2 and above.

    o  VCC calls various OS/390 UNIX System Services (USS)
       Interface modules provided by IBM to obtain
       information on Hierarchial File Systems residing on
       OS/390.