This is pretty new and requires a considerable amount of knowledge for DevOps too chain IBM has come up with in recent years. This page has excellent resources, please have a look:
Length of a Table field is wrong, subscript for array/s field is wrong, a record length is wrong, length of a defined field is wrong and it might make it exceed the record length of a given data-set - these can be some reasons among others.
? indicates a 1-byte indicator is to be included in each joined record. The indicator will be set to one of the following values in each paired or unpaired joined record, as appropriate: 'B' - the key was found in F1 and F2. '1' - the key was found in F1, but not in F2. '2' - the key was found in F2...
You might want to give an example of your specific situation. An educated guess is that you are talking about REFORMAT used in JOINKEYs, are you? Please elaborate.
"Modernization" might mean different to different people, depending on the context. As Robert has said, there is industry standard for it. Modernizing a mainframe system involves the adoption of applicable methodologies, installing modern hardware and or software. If not all, most of the t...
This is not different than any other conversion from one language to other. Though it becomes easy as both the languages are for mainframe. Google is your friend: see if this helps.
Endevor has an option called as "Batch Package". The option for this can vary shop to shop. However, the idea is to generate the JCL with it. Modify it per your need, proceed.