IBM OS/390 User Manual

Sequential DASD files are compatible between VSE and OS/390. However,
OS/390 does not support sequential (SAM) files located within VSAM managed
space. These files will have to be reloaded to different DASD areas before
OS/390 can process them.

DL/I databases are compatible with IMS databases 

1

 if the 

″

IMSCOMP

″

parameter was specified during the DL/I DBD generation. If this parameter was
not specified, then reloading of the database will be necessary; that is, a VSE
positioning activity. Similarly, DB2 for OS/390 provides compatibility with DB2 for
VSE. A section on database differences is included in this publication.

VSE DASD volumes can be read and processed by OS/390. VSE DASD

volumes, when first read by an OS/390 system, will have their free space areas
calculated and appropriate entries recorded in the volume

′

s VTOC. VSE systems

can later process these volumes as required. (Even though OS/390 has written
new records in the VTOC, VSE will ignore them.) Never, however, should both
systems have concurrent access to DASD volumes. Also, all volumes are required
by OS/390 to have unique volume serial numbers.

OS/390 operational procedures and operator commands differ significantly from
those used in VSE. The input/output spooling subsystems (VSE/POWER and
OS/390 JES) are quite different in function and operations also. Some of these
differences are addressed in this publication. 

Changing operational procedures and training of operators in the operations of
OS/390 are very important tasks that must be performed during a VSE to OS/390
migration. Training courses are available to assist in this effort.

Here is a list of some of the areas or programs that may be affected:

Table 1 (Page 1 of 3). Comparison of VSE Functions & Components to OS/390
Replacements

VSE Base Functions

IOCP
POWER (w/PNET, RJE)
EREP
M S H P
...

OS/390 Base Functions

IOCP, HCD *
JES2, JES3 (w/NJE, RJE) *
EREP *
SMP/E *
...

Application G e n e r a t o r s

VisualAge
VisualLift
SDF/CICS & SDF II
CSP
DMS/CICS

Application G e n e r a t o r s

VisualAge
VisualLift *
SDF II
CSP
DMS/CICS

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IMS databases are the OS/390 equivalent of VSE DL/I databases.

VSE to OS/390 Migration Workbook