Sounds like you clobbered the _IOWRT bit in the _flag field in _iob[2], or the _file field, or some such. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci (301) 454-7690 UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris CSNet: chris at umcp-cs ARPA: chris at maryland