<<Does anyone know of any kind of DEBUG facility for MPE/iX besides the one that comes with the OS. Someone metioned XDB.PUB.SYS, said it was a freebie from HP and it comes with MPE/iX.>> Not a "freebie"; "HP Symbolic Debugger/iX", a.k.a. "XDB", is a separate product. It is a source-level debugger that is supported by HP's C, FORTRAN, Pascal, and COBOL compilers on MPE/iX. Now as to why it isn't part of the package when you buy one of the language products.... Steve