The following three tables are used by data management to determine the type of data conversion to perform for ISO/ANSI tapes. See Character Data Conversion for a description of data conversion and how it is requested.

For purposes of these tables:

USER

Refers to the CCSID which describes the data used by the application program. It is derived from (in order of precedence):

1. CCSID parameter on the EXEC statement, or
2. CCSID parameter on the JOB statement.

If the table entry contains a 0, it means that the CCSID parameter was not supplied in the JCL. In this case, if data management performs CCSID conversion, a system default CCSID of 500 is used.

TAPE (DD)

Refers to the CCSID which is specified by the CCSID parameter on the DD statement, dynamic allocation, or TSO ALLOCATE. If the table entry contains a 0, it means that the CCSID parameter was not supplied. In this case, if data management performs CCSID conversion, a system default CCSID of 367 is used when open for output and not DISP=MOD.

Label

Refers to the CCSID which will be stored in the tape label during output processing (not DISP=MOD), or which is found in an existing label during DISP=MOD or input processing. Unless otherwise indicated in the tables, a CCSID found in the tape label overrides a CCSID specified on the DD statement on input.

Conversion

Refers to the type of data conversion data management will perform based on the combination of CCSIDs supplied from the previous three columns.

• Default denotes that data management performs conversion using Default Character conversion as described in Character Data Conversion. This conversion is used when CCSIDs are not supplied by any source.

  An existing data set created using Default Character conversion cannot be read or written (unless DISP=OLD) using CCSIDs.

• Convert a->b denotes that data management performs CCSID conversion with a and b representing the CCSIDs used.
• No conversion denotes that data management performs no conversion on the data.
• Fail denotes that the combination of CCSIDs is invalid. This results in an ABEND513-14 during open.

A CCSID of X, Y, or Z is used to represent any of the supported CCSIDs (other than 65␠535) where X ≠ Y ≠ Z. Unless otherwise specified in the tables, a CCSID of 65␠535 indicates that data management will perform no conversion.

Table 1 describes processing used when the data set is opened for output (not EXTEND) with DISP=NEW or DISP=OLD. The label column indicates what will be stored in the label.

Table 2 describes processing used when the data set is opened for output with DISP=MOD or when the OPEN option is EXTEND. This is only allowed for IBM created Version 4 tapes. Attempting to open a non-IBM created Version 4 tape with DISP=MOD will result in ABEND513-10.

Table 3 describes processing used when the data set is opened for INPUT or RDBACK.