MRC - Transient data VSAM control

       DESCRIPTIVE NAME = Transient Data VSAM Control
                          CICS/ESA AP Domain
           Licensed Materials - Property of IBM
            Restricted Materials of IBM 
           5655-Y04
           (C) Copyright IBM Corp. 1982, 1994 
      FUNCTION =
           Copybook DFHMRCPS provides structures, DFHMRCA and
           DFHMRCB and DFHMRSD.
           DFHMRCA describes the String Common Area (MRCA),
           only one MRCA is allocated.
           DFHMRCB describes the String Control Block (MRCB),
           one MRCB is allocated for each VSAM string.
           DFHMRSD describes the Segment Descriptor (MRSD),
           the number of MRSDs allocated depends on the size
           of the intrapartition data set.
      LIFETIME =
           The lifetime of the control blocks and I/O buffers
           is essentially that of CICS.
      STORAGE CLASS =
           The control blocks are located in storage allocated
           from the DFHTDG31 subpool.
           Note that the number of VSAM strings is defined as
           a SIT parameter / override.
      LOCATION =
           The MRCA is located from the TDST.
           MRCBs, if unallocated, are located on a chain whose
           anchor is located in the MRCA.
           MRSDs are located on a chain whose anchor is located
           in the MRCA.
           Note that the update ACB and output ACB are located
           from the MRCA.
           Note also that the RPL and VSAM Error Message Area
           (VEMA) are located from the associated MRCB.
      INNER CONTROL BLOCKS =
           There are no inner control blocks.
      NOTES :
       DEPENDENCIES =
           S/370
       RESTRICTIONS =
           There are no restrictions.
       MODULE TYPE =
           Control block definition.
                 MULTIPLE STRINGS - STRING COMMON AREA (MRCA)

                 MULTIPLE STRINGS - STRING CONTROL BLOCK (MRCB)

                 CI STATUS MAP - SEGMENT DESCRIPTOR (MRSD)

Constants