Shutting down cleanly ... sync; sync; sync;

I'm not sure when the halt and shutdown programs first appeared. I do recall that at least on V6 (mid 1970s) that the sync sequence was required whenever the system was shutdown. If the halt program existed then it only changed run level or issued a processor halt instruction. On the 11/45 I recall using the front panel to halt the processor after the sync sequence. THe halt program may not have appeared (or be commonly used) until after front panel started to disappear. I do vaguelly recall some discussion of this when we moved V6 to the 11/03. -- Dr. Mark Green mark(a)cs.ualberta.ca McCalla Professor (780) 492-4584 Department of Computing Science (780) 492-1071 (FAX) University of Alberta, Edmonton, Alberta, T6G 2H1, Canada