Since the MS-DOS 7.0 and higher COMMAND.COM executable is incompatible with DR-DOS, but typically resides in the root of drive C: in dual-boot scenarios with DR-DOS, DR-DOS 7.02 and higher no longer allow to bypass SHELL directives in (+)// "skip"/"trace"/"step" modes. (Some later issues added (+) to reinvoke the former "skip" behaviour in order to allow recovery from problems with invalid SHELL arguments as well.) Also, if no SHELL directive could be found when skipping CONFIG.SYS processing via (+) (and also with (+)/, when the default file extension has been changed with codice_9), the user is prompted to enter a valid shell file name "before" trying to load COMMAND.COM from the root. Pressing without specifying a file will assume the former default.