Joined: 06 Jun 2008 Posts: 8152 Location: East Dubuque, Illinois, USA
In general, C, Java, COBOL, PL/I or Assembler tend to be used for mainframe programming -- although I've used Perl a time or two as well. There are a number of databases in use such as DB2 and IDMS. Knowing how to use File/Aid, Abend-Aid, Xpediter, IBM's Debugging Tool, IBM utilities, and the sort tools are all good. For CICS debugging, knowing how to use CECI and CEDF help a lot. Being able to read a system dump and use IPCS can be helpful in some cases.
Knowing how to test is probably the biggest thing -- finding out how to do white-box and black-box tests, designing appropriate test cases, and documenting the testing process. Basically, mainframe testing is the same as any other testing -- look for places where the system specs don't match the provided system.