Debugging COBOL Programs HP COBOL II/XL runs on the MPE XL operating system. You can use the debuggers that run on MPE XL to debug your HP COBOL II/XL programs. They are Debug (the MPE XL System Debugger) and[REV BEG] one of two symbolic debuggers: HP Symbolic Debugger/XL or HP TOOLSET/XL.[REV END]