All IBM mainframe and midrange peripherals and operating systems use EBCDIC as their inherent encoding[REF] (with toleration for ASCII, for example, ISPF in z/OS can browse and edit both EBCDIC and ASCII encoded files).
IBM AIX running on the RS/6000 and its descendants including the IBM Power Systems, Linux running on z Systems, and operating systems running on the IBM PC and its descendants use ASCII, as did AIX/370 and AIX/390 running on System/370 and System/390 mainframes.