1. path name SYSX/BILL
  compiler: wrote debug output
  BILL: debug: compiled main.f
2. fd of alice/debug.txt
  compiler: wrote debug output
  alice reads debug.txt: debug: compiled main.f
  BILL: alice 3h 1200yen
3. fd of SYSX/BILL
  alice: cannot open BILL: Permission denied
  BILL: alice 3h 1200yen
4. read-only fd of alice/notes.txt
  compiler: OSError: Bad file descriptor
  alice reads notes.txt: (empty)
  BILL: alice 3h 1200yen
STAT: 3 lines written with the compiler's own authority