IBM OS/390 User Manual
cannot be converted entirely automatically, and for which the unresolved
conversion requirement cannot be addressed through VSE positioning.
conversion requirement cannot be addressed through VSE positioning.
32.5 Conversion Phases
The specific phases included in the Conversion Activities are:
•
Initial Trial Conversions
•
OS/390 Regression Tests and Repeated Trial Conversions
The objective of the conversion phases is to automatically mass convert the
inventory of production source code and JCL to OS/390, to deliver functionally
equivalent OS/390 material (source code, load modules, run JCL, and JCL
procedures), and to generate VSE to OS/390 file migration JCL procedures.
inventory of production source code and JCL to OS/390, to deliver functionally
equivalent OS/390 material (source code, load modules, run JCL, and JCL
procedures), and to generate VSE to OS/390 file migration JCL procedures.
The phases end when the quality of the conversion is deemed satisfactory and
all critical applications such as daily, weekly, and online applications have been
successfully tested under OS/390.
all critical applications such as daily, weekly, and online applications have been
successfully tested under OS/390.
32.5.1 Program Conversion
The mass conversion key steps relative to program conversion are:
Program Conversion
Generates OS/390 source code and extract some
information required for VSE JCL conversion, such as:
files opened, their device types, assignments, block sizes,
and open mode (input, output); entry-points; referenced
macros, copybooks, includes or sub-programs.
information required for VSE JCL conversion, such as:
files opened, their device types, assignments, block sizes,
and open mode (input, output); entry-points; referenced
macros, copybooks, includes or sub-programs.
Compilation/Link-Edit
Starts from the OS/390 version of the source code to
generate executable code (load modules).
generate executable code (load modules).
32.5.1.1 Program Conversion Considerations
The following considerations are recommended to be performed during (or prior
to) your migration to OS/390.
to) your migration to OS/390.
•
After all VSE programs are identified and collected for the conversion
process, they must be compiled in VSE to detect if there are any
source/object discrepancies with VSE production. This ensures that the
correct level of the program (source) is used.
process, they must be compiled in VSE to detect if there are any
source/object discrepancies with VSE production. This ensures that the
correct level of the program (source) is used.
•
To be as compatible as possible to OS/390 requirements, VSE programs
should be compiled using the latest levels of the VSE compilers. Migration
to the Language Environment for VSE and the Language Environment
enabled language compilers is strongly recommended.
should be compiled using the latest levels of the VSE compilers. Migration
to the Language Environment for VSE and the Language Environment
enabled language compilers is strongly recommended.
•
Any VSE program without source code must be rewritten. Products are
currently available that will allow source to be recovered (or reconstructed)
from executable modules.
currently available that will allow source to be recovered (or reconstructed)
from executable modules.
•
RPG CICS programs, if any exist, must be rewritten in another high-level
language.
language.
•
All ISAM programs must be converted to VSAM.
•
BDAM programs must be converted to relative record VSAM where possible.
•
VSE programs using the UPSI and/or the DATE statement facility will have to
have this function simulated in another fashion. In OS/390 either use the
EXEC card
have this function simulated in another fashion. In OS/390 either use the
EXEC card
″
PARM
″
facility (similar to the VSE PARM parameter introduced in
Chapter 32. Conversion Process
503