IBM OS/390 User Manual
Please contact your local IBM Representative for more information on how to
access IBM manuals via the INTERNET.
access IBM manuals via the INTERNET.
Another useful INTERNET location
′
http://www.hursley.ibm.com/cics
′,
is the CICS
home page.
The CICS Internet Home page provides a service/support segment that allows
easy access to a wide range of material that complements the CICS Family of
products. As part of the Service and Support segment, user forums are available
for CICS migration tidbits and Qs and As.
easy access to a wide range of material that complements the CICS Family of
products. As part of the Service and Support segment, user forums are available
for CICS migration tidbits and Qs and As.
Also, the CD-ROM collect kits, can be a useful source for IBM manuals. The
Collection Kit for Transaction Processing and Data Products, SK2T-0730 includes
the unlicensed manuals except for:
Collection Kit for Transaction Processing and Data Products, SK2T-0730 includes
the unlicensed manuals except for:
•
CICS Master Index, SC33-1704
•
CICS Transaction Server for OS/390 Licensed Program Specifications,
GC33-1707.
GC33-1707.
6.1.3 General Compatibility Comments
One of the strengths of the CICS products is the portability of the Command
Level API between operating systems. However, applications that include Report
Controller API
Level API between operating systems. However, applications that include Report
Controller API
cannot be migrated and there is no printer and spool file
manipulation facilities available in the CICS TS environment. Thus, you should
prepare alternate solutions (such as, MVS LAN/RES, user written programs,
TCP/IP print daemons, vendor packages) if your users require the same or
similar functions or identify the service as no longer available (the sooner the
better) to the users.
prepare alternate solutions (such as, MVS LAN/RES, user written programs,
TCP/IP print daemons, vendor packages) if your users require the same or
similar functions or identify the service as no longer available (the sooner the
better) to the users.
CICS system facilities will differ between the two operating systems. Facilities
based upon the operating system architecture and product-unique (VSE, MVS)
functions will have to be re-worked during the conversion to OS/390. One
significant change will be the effects on performance and tuning. OS/390 will
accommodate additional resources and larger buffer pools resulting in I/O
reductions, improved response times, and higher transaction rates. It will also
introduce new tuning controls such as the MVS Systems Resource Manager
(SRM) that can provide more consistent response times. For these reasons, a
stress test of the CICS/MVS system should be a part of the overall MVS
migration plan. The major differences between VSE and MVS CICS application
programs can be attributed to unique facilities provided by the programming
languages or the operating systems. As long as CICS application programs have
adhered to standard CICS programming interfaces outlined in the
based upon the operating system architecture and product-unique (VSE, MVS)
functions will have to be re-worked during the conversion to OS/390. One
significant change will be the effects on performance and tuning. OS/390 will
accommodate additional resources and larger buffer pools resulting in I/O
reductions, improved response times, and higher transaction rates. It will also
introduce new tuning controls such as the MVS Systems Resource Manager
(SRM) that can provide more consistent response times. For these reasons, a
stress test of the CICS/MVS system should be a part of the overall MVS
migration plan. The major differences between VSE and MVS CICS application
programs can be attributed to unique facilities provided by the programming
languages or the operating systems. As long as CICS application programs have
adhered to standard CICS programming interfaces outlined in the
CICS
Application Programmer
′
s Reference Manual(s) (APRM), the migration or
conversion effort should be minimal. In most cases only a CICS/MVS translation
and compilation will be required. If the applications are using non-CICS functions
such as GET/PUT or COMREG, they may require significant recoding.
and compilation will be required. If the applications are using non-CICS functions
such as GET/PUT or COMREG, they may require significant recoding.
6.1.4 Virtual Storage Considerations for MVS
To minimize change during the migration to MVS, the general recommendation
is to bring multiple CICS/VSE systems across to MVS the same as they are in
the VSE environment. That is, if you have two or more independent production
CICS systems under VSE, you would want multiple independent production CICS
systems under MVS. MVS/ESA provides considerable virtual storage constraint
relief for CICS systems. This is due to the ability to place almost all management
modules, and many control blocks above the 16 megabyte line. In addition,
is to bring multiple CICS/VSE systems across to MVS the same as they are in
the VSE environment. That is, if you have two or more independent production
CICS systems under VSE, you would want multiple independent production CICS
systems under MVS. MVS/ESA provides considerable virtual storage constraint
relief for CICS systems. This is due to the ability to place almost all management
modules, and many control blocks above the 16 megabyte line. In addition,
Chapter 6. CICS
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