diff --git a/build/build.tcl b/build/build.tcl
index 80460290..26b187d6 100644
--- a/build/build.tcl
+++ b/build/build.tcl
@@ -178,6 +178,7 @@ if {$env(BASICS)!="yes"} {
 	source $build/macsyma.tcl
     }
     source $build/scheme.tcl
+    source $build/dm.tcl
     source $build/muddle.tcl
     source $build/sail.tcl
     source $build/typeset.tcl
diff --git a/build/dm.tcl b/build/dm.tcl
new file mode 100644
index 00000000..cbb45bdd
--- /dev/null
+++ b/build/dm.tcl
@@ -0,0 +1,8 @@
+log_progress "ENTERING BUILD SCRIPT: DM"
+
+# This build script is for programs particular to the
+# Dynamic Modeling PDP-10.
+
+# Demon starter.
+respond "*" ":midas sys; atsign demstr_sysen2; demstr\r"
+expect ":KILL"
diff --git a/doc/programs.md b/doc/programs.md
index e3e82962..f0f97f5a 100644
--- a/doc/programs.md
+++ b/doc/programs.md
@@ -86,6 +86,7 @@
 - DCROCK, digital watch.
 - DDTDOC, interactive DDT documentation.
 - DECUUO, TOPS-10 and WAITS emulator.
+- DEMSTR, demon starter.
 - DFTP, Datacomputer file transfer.
 - DIGEST, digestify a mailing list.
 - DIRCPY, copy directory.
diff --git a/src/sysen2/demstr.49 b/src/sysen2/demstr.49
new file mode 100755
index 00000000..1b248058
--- /dev/null
+++ b/src/sysen2/demstr.49
@@ -0,0 +1,34 @@
+	TITLE DEMSTR - STARTUP DEMON - MB 9/27/73
+
+.MLLIT==1
+
+DEFINE DEMSIG NAME,ARG,ZZZ
+	.CALL	[SETZ ? 'DEMSIG
+		[SIXBIT /NAME/]
+		SETZ [ARG]]
+	 TDZA	;FAIL, SET SNOOZE TO 0
+	MOVEI	30.*ZZZ
+	.SLEEP
+TERMIN
+
+;INSTALL A DEMON AT THE END OF THE LIST:
+; FIRST ARG IS NAME OF FILE "SYS;ATSIGN NAME" TO LOAD.
+; SECOND ARG IS REPETITION TIME (2 MINS), OR 0 FOR NONE, OR -1 FOR LOAD WITHOUT SIGNAL.
+; THIRD ARG IS TIME (SEC) FOR DEMSTR PROGRAM TO SLEEP AFTER SIGNALLING DEMON.
+
+START:	.DEMON		; I HAVE ARRIVED
+	JFCL		; SOMETHING IS WRONG, BUT OK ANYWAY
+
+	DEMSIG	EGG,-1,10.		; PFTHMG DRAGON
+	DEMSIG	PAPSAV,0,10.		; SPYER ON T00; SWG 3/31/81
+	DEMSIG	UNSPOO,0,10.		; PRINTER UNSPOOLER
+;	DEMSIG	SURVEY,10.,15.		; ARPANET HOST SURVEY; SWG
+	DEMSIG	COMSAT,0,10.		; MAIL DEMON; SWG 1/26/83
+	DEMSIG	ZONE,0,60.		; MUDDLE COMPILE BATCHER
+	DEMSIG	BATCHN,0,60.		; NEW BATCH MONITOR; SWG
+;	DEMSIG	GUNNER,0,10.		; GARBAGE MAN; TAA 12/8/77
+	DEMSIG  EXPIRE,-1,10.		; GMSGS CLEANER; CSTACY 4/8/83
+
+	.LOGOUT
+	.VALUE
+END	START