DDTF is a find-string command add-on for DDT, SID, ZSID, or other
CP/M 2.2 debugger.  DDTF5 is invoked in the same fashion that DDT,
SID, or any other debugger is invoked.  You can type "DDTF5
PROGNAME.COM" to load a program called PROGNAME.COM into memory
under your debugger and DDTF5.  Or you can simply type "DDTF5" to
load your debugger and DDTF5 by themselves.  Version 5 has a
stronger self-protection algorithm, to protect against removal by
other utilities that may already be resident below the CCP.  (Some
such utilities would remove DDTF between the time it invoked the
debugger and the time the debugger was loaded.)