Meaning of MPREFIX

The MPREFIX parameter (KI2_I1nn_CLASSIC_MPREFIX in PARMGEN) specifies the value to be used as the suffix for all unique members that are required for each RTM task, with the exception of the KIPGLBxx global parameters member. MPREFIX also specifies the center value of KOImpP00, that is, the start member in RKANPAR.

In addition, the MPREFIX value is used as the first 2 characters of an internally generated MVS™ modify ID. It is also used in the JCL member for the MPREFIX parameter value and in many RKANPAR, RKANSAM, and RKANCMD members. The KIPGLBxx global parameters member supports a unique suffix; however, the suffix defaults to MPREFIX.

The 2-byte MPREFIX is coded as a standard OS name. The first character is alphabetical because it is the beginning of the MVS modify ID. The second is alphanumeric. The default MPREFIX values are generated as xn, where xn is constructed as follows:
  • Number of tasks <= 16: xn = M0..MF
  • Number of tasks > 16: xn = N0..N9-V0..V2 (The default is M0.)