Chapter 10: File Handling

This chapter describes differences in file handling between COBOL Workbench and Mainframe Express that might require you to make alterations in existing applications that you are migrating, or to change familiar methods of working.

10.1 Overview

The biggest difference in file handling is the use of catalogs in Mainframe Express. These will be familiar to mainframe users. In turning a COBOL Workbench application into a Mainframe Express project, you can use the Mfextmap Migration Tool (see below) to populate your catalog.

You don't need the catalog if your application only uses IMS or SQL databases or files managed by CICS.

Apart from that, file handling is unchanged, but there are differences in the tools available. These changes are given in the next section.

10.2 Details

This section advises on what to use where a COBOL Workbench feature is not in Mainframe Express or has changed. Where we believe you can continue using a COBOL Workbench feature without change, it is not mentioned. This book does not cover enhancements.


10.2.1 Filename Mapping

Facility to use an environment variable to map a COBOL filename to a physical file on disk.

Status in Mainframe Express:

Included, but the recommended method is to use the catalog to perform DD mappings.


10.2.2 FSView

Utility to monitor running of Fileshare applications.

Status in Mainframe Express:

Not included.


10.2.3 File Transfer Aid

Utility to transfer files between the PC and the mainframe

Status in Mainframe Express:

Not included.

What to use instead:

MFA Drag & Drop does a similar job to File Transfer Aid. You can upload and download files, and have them automatically converted between character sets. You can also use SourceConnect and DataConnect to have files participate fully in your application while leaving them residing on the mainframe.

You need the separate Micro Focus product Mainframe Access (MFA) running on the mainframe to use these facilities.


10.2.4 Mfextmap.dat

File to correlate DD names used in COBOL programs to their associated PC filenames.

Status in Mainframe Express:

Usable for backward compatibility.

To migrate your application:

See the chapter Your Mfextmap File.

What to use for future applications:

Create entries in the project catalog (using the Allocate or Add Existing Dataset function or the MFJAMS utility) for the datasets used by the project and ensure JCL DD or TSO ALLOCATE statements are used before the program is invoked.


10.2.5 RUNITLOCKDETECT

Setting in extfh.cfg configuration file to determine whether locks set within one run unit are recognized by other programs within that same run unit.

Status in Mainframe Express:

Included, with the following change - the default is now ON. The format of this entry is:

Entry Default Tag Effect
RUNITLOCKDETECT=ON/OFF ON [xfh-default] Locks are recognized by other programs in the same run unit

10.2.6 XFHTRACE

Utility to generate trace information on file handling, which can be used by Micro Focus to help in problem determination.

Status in Mainframe Express:

Included, with the following change. Control of XFHTRACE is now done not with a separate configuration file but via the standard file handling configuration file, extfh.cfg. The entries to control XFHTRACE are:

Entry Default Tag Effect
TRACE=ON/OFF OFF The tag for the file, or [xfh-default] to affect all files. Turns tracing on or off
TRACEFILE=filename xfhtrace.xfh [xfh-default] File to contain the trace information.

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