term% ls -F
term% cat index.txt
RDBFS(4)                   Kernel Interfaces Manual                   RDBFS(4)

       rdbfs - remote kernel debugging file system

       rdbfs [ -d ] [ -p pid ] [ -s srvname ] [ -t text ] [ device ]

       Rdbfs  presents  in  /proc/pid (default /proc/1) a set of process files
       for debugging a kernel over the serial line device (default /dev/eia0).
       If  the -s option is given, rdbfs will post its channel in /srv/srvname
       (see srv(3)), allowing the session to be shared or reattached later.

       The text file presented is just a copy of text (default /386/9pc).   It
       can  usually be ignored, since the debuggers open kernel files directly
       rather than using /proc/n/text.

       Kernels can be remotely debugged  only  when  they  are  suspended  and
       serving  a  textual debugging protocol over their serial lines.  Typing
       ``^t^td'' (control-t, control-t, d) at the console will cause the  ker‐
       nel  to  enter this mode when it `panics'.  Typing ``^t^tD'' causes the
       kernel to enter this mode immediately.

       Because the debugging protocol is textual, a console provided  by  con‐
       solefs(4) may be substituted for the serial device.


       acid(1), db(1), consolefs(4)