The equivalent in Mainframe Express of the Micro Focus IMS Option (MFIMS) add-on for Workbench is also called IMS Option. It is an option that adds IMS support to the IDE, and is based on the IMS Option for Workbench. This chapter describes differences between the Workbench IMS Option and the Mainframe Express IMS Option that might require you to make alterations in existing applications that you are migrating, or to change familiar methods of working.
To use this feature, you need to have installed IMS Option when you ran Setup to install Mainframe Express.
This chapter covers migration from IMS Option 2.5 or IMS Option 3.1.
This section advises on what to use where a feature in IMS Option for Workbench is not in Mainframe Express or has changed. Where we believe you can continue using a feature without change, it is not mentioned. This book does not cover enhancements.
IMS Option in Mainframe Express provides upward compatibility of all gen and database files from IMS Option 2.5 and IMS Option 3.1. Re-gens or database reloads are not necessary. In addition, gen files and database files produced in Mainframe Express are downward compatible to IMS Option 3.1, but not to IMS Option 2.5. However, there is one exception to both these statements.
MFSGEN members that contain special characters such as ¬, !, ^, [, ], or | in literal strings are not upward or downward compatible between Mainframe Express and IMS Option for Workbench. This is because different conversion tables are used for ANSI/EBCDIC translation. This only affects non-alphanumeric special characters when used in MFS literals. Affected MFS members should be regenned in Mainframe Express.
IMS Option 3.1 supported two formats of PSBGEN files; PSBGEN3 and PSBGEN2 formats. It also included a conversion utility to convert from one format to the other. PSBGEN2 format allowed for downward compatibility with version 2.5 and PSBGEN3 provided improved performance and reduced software limitations. Mainframe Express supports both PSBGEN formats for input but will automatically convert the older PSBGEN2 format file to a PSBGEN3 format when a PSB is compiled.
IMS Option in Mainframe Express supports the concatenation of gen libraries. In IMS Option for Workbench this was achieved using the IMSLIB through IMSLIB10 environment variable settings. In IMS Option in Mainframe Express, it is implemented through the Workgrouping Load Libraries. See your IMS Option Technical Guide.
IMS Option system APIs have not changed in Mainframe Express but the call to make these entry points available has changed. The environment variable IMSDIR is no longer used to indicate the location of IMS Option system programs. Therefore, programs which issue the code:
CALL '$IMSDIR\PCIMS.LBR'
to load IMS Option entry points should be changed to use:
CALL 'PCIMS.LBR'
Sample programs which demonstrate calling IMS Option APIs have been adjusted for this change. If you are migrating existing programs which call IMS Option system APIs, please review your code for this change.
When migrating an IMS86ENT.CBL program from a previous version some modifications may be required. The sample IMS86ENT.CBL program supplied with IMS Option 3.1 contained the following code in both the 1000-INIT and the 2000-CALL paragraphs:
IF IMS86GIO-INFO-VER-NO < '3.1.00'
This code assumed that a version number less than 3.1 indicated an older IMS Option product. This is not true in Mainframe Express as the version number returned in IMS86GIO-INFO-VER-NO will be less than 3.1. If you are migrating IMS86ENT.CBL from a previous version, you should change or remove this code. Please refer to the IMS86ENT.CBL shipped with Mainframe Express if you are uncertain of these changes.
If you are migrating IMS86ENT.CBL from IMS Option for Workbench and you had added a call to MF370RST, you should now remove this call. This call was used to help synchronize the canceling of COBOL and Assembler application programs from memory. This synchronization is now coordinated between IMS Option and Assembler Option and the workaround of calling MF370RST is no longer required.
In IMS Option for Workbench, Assembler application programs that use the ASMTDLI entry point were required to assemble and link the supplied program ASMTDLI.MLC. Mainframe Express no longer requires this procedure. Assembler Option automatically detects and resolves DL/I entry points in Assembler application programs. If you are migrating an application which includes ASMTDLI.MLC, you should remove this file.
A Mainframe Express client can connect to an older non-Mainframe Express Fileshare server for support of shared update databases. However, if the non-Mainframe Express Fileshare server includes the IMS Supervisor program (IMSSUPER), it must be version 3.1.53 or later.
Support for data capture exits was introduced in IMS Option 3.1.18. A database which was genned with IMS Option for Workbench will not support data capture exits. You must perform a DBDGEN for each DBD which contains data capture exit definitions if you want to enable this functionality.
If you have customized your own xxxTDLI interface using the USRTDLI.CBL sample program supplied with IMS Option 3.1.17 or earlier, you will need to make a minor change to this xxxxTDLI program. If the xxxxTDLI program is called by both a data capture exit program and your application program, it will need to have a Local-Storage Section added, so it can be called recursively. See the USRTDLI.CBL sample program installed with Mainframe Express for the syntax you should use. It is installed in \mfe\mfims\source.
The glue module IMS2ASM.MLC from IMS Option 3.1.17 and earlier does not support data capture exits. We recommend that you use the IMS2ASM.MLC program that is installed with Mainframe Express. It is installed in \mfe\mfims\source.
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