Mainframes use EBCDIC data format, which presents a challenge as most modern systems use ASCII data format. In addition data structures of the mainframe data can be complex and are generally specified through COBOL copybook records. The complications are related nested field, packed-decimals, arrays and REDEFINES making code translations complex and difficult to achieve. In this how-to guide we will provide information on how to process variable length / block or field length and block EBCDIC files.
This how-to does not cover on how to bring data from mainframes. There are various way to bring datasets from DB2 or IMS. This how-to assume, you have used DBMS export utilities to bring datasets into flat files.
Before Start
Store ECBDIC data on GCS
EBCDIC data exported from mainframes can be stored on GCS in the same way we store any other files. The files are binary and require COBOL copybook to interpret them. This presents the challenge for debugging issues with data or system.
Access to COBOL Copybook
For processing the EBCDIC data, one would need a copybook that defines the structure of the data within the EBCDIC file.
More than one copybook might be required to process all the data in the file. This means records with different structures can exist within the same file.
Understanding file(s) exported from mainframe
Datasets (or dataset partitions) can be exported in various way from DB2 or IMS. It’s important to understand if the file was text or binary, what record format was used to export the file (
Steps
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