When you use READ and WRITE macros, errors are detected when you issue a CHECK macro. If you are processing a direct data set, sequential data set, or PDS and you return to the control program from your SYNAD routine, the operating system assumes that you have accepted the bad block. If you are creating a direct data set and you return to the control program from your SYNAD routine, your task ends abnormally. If you are processing a direct data set, make the return to the control program through register 14 to make an internal system control block available for reuse in a READ or WRITE macro.