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automated conversion defects. The switchover of an entire VSE production to
OS/390 over a weekend cannot be improvised: it requires perfect precision and
planning by experienced conversion specialists. The complexity of powerful
mass conversion tools makes it difficult to staff with internal
non-conversion-expert staff exclusively, because of the learning curve. Hiring
conversion consultants experienced with mass conversions and single weekend
switchovers is highly recommended for users who want to migrate large
integrated VSE production environments to OS/390 over a single weekend.
3.3.9.1 Mass Migration as a Conversion Method
Mass migration uses the single switchover method of migrating a VSE
installation to OS/390. The various conversion tasks that need to be performed
using this methodology are described in the MVS-MS and CORTEX-MS
documentation. The conversion method, or process, consists of running three
conversions:
1. The pilot conversion - a conversion of a small subset of the VSE applications,
usually involving all or part of the most important work. The pilot conversion
educates project team members, provides the time to define OS/390
standards, code any exits deemed necessary for customizing, and overall
prepares the team for the rest of the conversions.
2. The dummy conversion - a conversion of all VSE applications; a process that
is normally repeated many times as changes are made to VSE source
materials over the life of the project. This is why ″freezing″ VSE application
maintenance is not necessary with this methodology.
3. The actual mass conversion (or switchover) - a conversion of all VSE
applications, the switchover of the VSE files and catalogs, followed by OS/390
production operations.
Because MVS-MS and CORTEX-MS documentation guides you in the steps and
tasks to be performed, it helps you develop a comprehensive and detailed
migration plan for your own installation. The documentation also provides the
skeleton migration plan with staffing recommendations - you provide your
installation-specific details.
3.3.9.2 Mass Migration Used as a Conversion Tool
Used interactively, MVS-MS or CORTEX-MS is a set of subsystems that are panel
driven and use TSO terminals to direct all conversion tasks. The tool translates
VSE source programs written in the following languages:
•
Assembler
•
COBOL
•
PL/I Optimizer
•
RPG II
In addition to translating the above VSE programming language programs into
OS/390 source equivalents, MVS-MS or CORTEX-MS, herein after referred to as
the tool, also performs the following:
•
ISAM programs are translated to VSAM; that is, ISAM I/O statements
translated into VSAM statements.
•
COMREG, CNTRL, and PRTOV functions (VSE functions not directly supported
in OS/390) are simulated under OS/390 by the tool′s simulation routines.
52 VSE to OS/390 Migration Workbook