diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5169ac8a..7182a0b2 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -15,6 +15,21 @@ jobs:
           timeout: 120m
       - store_artifacts:
           path: out
+  build_kl10:
+    docker:
+      - image: debian
+    environment:
+      EMULATOR: "pdp10-kl"
+    steps:
+      - checkout
+      - run: sh -ex build/dependencies.sh install_linux
+      - run:
+          name: build
+          command: "make check-dirs all EMULATOR=$EMULATOR"
+          no_output_timeout: 30m
+          timeout: 120m
+      - store_artifacts:
+          path: out
   build_klh10:
     docker:
       - image: debian
diff --git a/.travis.yml b/.travis.yml
index df210b87..8826e8e0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,12 +8,15 @@ env:
   - EMULATOR=simh BASICS=yes
   - EMULATOR=klh10 BASICS=yes
   - EMULATOR=pdp10-ka BASICS=yes
+  - EMULATOR=pdp10-kl BASICS=yes
 matrix:
   exclude:
     - os: osx
       env: EMULATOR=klh10 BASICS=yes
     - os: osx
       env: EMULATOR=pdp10-ka BASICS=yes
+    - os: osx
+      env: EMULATOR=pdp10-kl BASICS=yes
 install: sh -ex build/dependencies.sh install_${TRAVIS_OS_NAME:-linux}
 script: make check-dirs all
 deploy:
diff --git a/Makefile b/Makefile
index ee70ad68..1bd35bfc 100644
--- a/Makefile
+++ b/Makefile
@@ -43,7 +43,7 @@ MINSRC = midas system $(DDT) $(SALV) $(KSFEDR) $(DUMP)
 # These are not included on the tape.
 DOCIGNORE=-e '\.(jpeg|pdf|info|md)$$' -e '^(dcg|github)$$'
 # These are on the minsys tape.
-BINIGNORE=-e '^(ka10|ks10|minsys)$$'
+BINIGNORE=-e '^(ka10|kl10|ks10|minsys)$$'
 # These are on the minsrc tape.
 SRCIGNORE=-e '^(system|midas)$$'
 
@@ -57,6 +57,7 @@ DSKDMP = bin/ks10/boot/dskdmp.rp06
 KLH10=tools/klh10/tmp/bld-ks-its/kn10-ks-its
 SIMH=tools/simh/BIN/pdp10
 KA10=tools/sims/BIN/pdp10-ka
+KL10=tools/sims/BIN/pdp10-ka
 ITSTAR=tools/itstar/itstar
 WRITETAPE=tools/tapeutils/tapewrite
 MAGFRM=tools/dasm/magfrm
@@ -85,15 +86,24 @@ out/simh/stamp: $(OUT)/rp0.dsk $(GT40)
 out/pdp10-ka/stamp: $(OUT)/rp03.2 $(OUT)/rp03.3 $(GT40) $(TV11) $(PDP6)
 	$(TOUCH) $@
 
+out/pdp10-kl/stamp: $(OUT)/rp04.1
+	$(TOUCH) $@
+
 $(OUT)/rp0.dsk: build/simh/init $(OUT)/minsys.tape $(OUT)/minsrc.tape $(OUT)/salv.tape $(OUT)/dskdmp.tape build/build.tcl $(OUT)/sources.tape build/$(EMULATOR)/stamp
 	PATH="$(CURDIR)/tools/simh/BIN:$$PATH" expect -f build/$(EMULATOR)/build.tcl $(IP) $(GW)
 
 $(OUT)/rp03.2 $(OUT)/rp03.3: $(OUT)/ka-minsys.tape $(OUT)/minsrc.tape $(OUT)/magdmp.tap $(OUT)/sources.tape
 	$(EXPECT) -f build/$(EMULATOR)/build.tcl $(IP) $(GW)
 
+$(OUT)/rp04.1: $(OUT)/kl-minsys.tape $(OUT)/minsrc.tape $(OUT)/kl-magdmp.tap $(OUT)/sources.tape
+	$(EXPECT) -f build/$(EMULATOR)/build.tcl $(IP) $(GW)
+
 $(OUT)/magdmp.tap: $(MAGFRM)
 	cd bin/ka10/boot; ../../../$(MAGFRM) magdmp.bin @.ddt @.salv > ../../../$@
 
+$(OUT)/kl-magdmp.tap: $(MAGFRM)
+	cd bin/kl10/boot; ../../../$(MAGFRM) magdmp.bin @.ddt salv.bin > ../../../$@
+
 $(OUT)/minsrc.tape: $(ITSTAR)
 	$(MKDIR) $(OUT)
 	$(ITSTAR) -cf $@ -C src $(MINSRC)
@@ -109,6 +119,11 @@ $(OUT)/ka-minsys.tape: $(ITSTAR) $(OUT)/system
 	$(ITSTAR) -cf $@ -C bin/ka10 _ sys
 	$(ITSTAR) -rf $@ -C bin/minsys sys
 
+$(OUT)/kl-minsys.tape: $(ITSTAR) $(OUT)/system
+	$(MKDIR) $(OUT)
+	$(ITSTAR) -cf $@ -C bin/kl10 _ sys
+	$(ITSTAR) -rf $@ -C bin/minsys sys
+
 $(OUT)/sources.tape: $(ITSTAR) build/$(EMULATOR)/stamp $(OUT)/syshst/$(H3TEXT)
 	$(MKDIR) $(OUT)
 	$(RM) -f src/*/*~
@@ -156,6 +171,9 @@ build/simh/stamp: $(SIMH) start
 build/pdp10-ka/stamp: $(KA10) start
 	$(TOUCH) $@
 
+build/pdp10-kl/stamp: $(KL10) start
+	$(TOUCH) $@
+
 out/klh10/system:
 	$(MKDIR) $(OUT)/system
 	cp=0; ca=0; \
@@ -174,6 +192,10 @@ out/pdp10-ka/system:
 	$(MKDIR) $(OUT)/system
 	cp build/pdp10-ka/config.* $(OUT)/system
 
+out/pdp10-kl/system:
+	$(MKDIR) $(OUT)/system
+	cp build/pdp10-kl/config.* $(OUT)/system
+
 build/klh10/dskdmp.ini: build/klh10/dskdmp.txt Makefile
 	cp=';'; ca=''; \
 	$(TEST) $(CHAOS) != no && cp='' && ca='myaddr=$(CHAOS) $(CHAFRIENDS)'; \
@@ -207,6 +229,9 @@ $(SIMH):
 $(KA10):
 	$(MAKE) -C tools/sims pdp10-ka TYPE340=y
 
+$(KL10):
+	$(MAKE) -C tools/sims pdp10-ka
+
 $(ITSTAR):
 	$(MAKE) -C tools/itstar
 
diff --git a/build/kl10/include.tcl b/build/kl10/include.tcl
index eaebbe4e..834d2b2a 100644
--- a/build/kl10/include.tcl
+++ b/build/kl10/include.tcl
@@ -1,9 +1,161 @@
-make_ntsddt {} {
+proc start_dskdmp_its {} {
+    start_dskdmp build/pdp10-kl/boot
+
+    respond "DSKDMP" "ddt\r"
+    respond "\n" "\033l"
+    respond " " "its bin\r"
+    respond "\n" "\033\033l"
+    respond " " "salv bin\r"
+    respond "\n" "\033y"
+    respond " " "its\r"
+    patch_its_and_go
+}
+
+proc mark_packs {} {
+    respond "\n" "mark\033g"
+    respond "UNIT #" "0"
+    respond "#0?" "y"
+    respond "NO =" "0\r"
+    respond "ALLOC =" "3000\r"
+    respond "PACK ID =" "0\r"
+}
+
+proc prepare_frontend {} {
+}
+
+proc frontend_bootstrap {} {
+}
+
+proc its_switches {} {
+    respond "MACHINE NAME =" "KL\r"
+}
+
+proc make_ntsddt {} {
     # KL10 NTSDDT.
-    respond "*" ":midas dsk0:.;@ ntsddt_system;ddt\r"
-    respond "cpusw=" "2\r"
+    respond "*" ":midas dsk0:.;@ ddt_system;ddt\r"
+    respond "cpusw=" "0\r"
     respond "ndsk=" "1\r"
     respond "dsksw=" "3\r"
-    respond "1PRSW=" "1\r"
+    respond "1PRSW=" "0\r"
     expect ":KILL"
 }
+
+proc make_salv {} {
+    respond "*" ":midas dsk0:.;_system;salv\r"
+    respond "time-sharing?" "n\r"
+    respond "machine?" "KL\r"
+    expect ":KILL"
+}
+
+proc make_dskdmp {} {
+    respond "*" ":midas dsk0:.;@ dskdmp_system;dskdmp\r"
+    expect "Configuration"
+    respond "?" "ASK\r"
+    respond "HRIFLG=" "N\r"
+    respond "BOOTSW=" "N\r"
+    respond "RP06P=" "N\r"
+    respond "RP07P=" "N\r"
+    respond "RM03P=" "N\r"
+    respond "RM80P=" "N\r"
+    respond "RH10P=" "Y\r"
+    respond "NUDSL=" "500.\r"
+    respond "KS10P=" "N\r"
+    respond "KL10P=" "N\r"
+    expect ":KILL"
+}
+
+proc dump_switches {} {
+    respond "WHICH MACHINE?" "KL\r"
+}
+
+proc peek_switches {} {
+    respond "with ^C" "\003"
+}
+
+proc dump_nits {} {
+    # Run the new DSKDMP from disk here, to check that it works.
+    respond "DSKDMP" "dskdmp\r"
+
+    respond "DSKDMP" "l\033ddt\r"
+
+    # Dump an executable @ SALV.
+    respond "\n" "t\033salv bin\r"
+    respond "\n" "\033y"
+    respond " " "salv\r"
+
+    # Now dump the new ITS.
+    respond "\n" "\033l"
+    respond " " "its bin\r"
+    respond "\n" "\033\033l"
+    respond " " "salv bin\r"
+    respond "\n" "\033y"
+    respond " " "nits\r"
+}
+
+proc magdmp_switches {} {
+    respond "KL10P=" "n\r"
+    respond "TM10BP=" "y\r"
+    respond "340P=" "n\r"
+}
+
+proc bootable_tapes {} {
+    global emulator_escape
+    global out
+
+    respond "*" ":midas .;magdmp bin.kl_syseng;magdmp\r"
+    respond "PTRHRI=" "n\r"
+    magdmp_switches
+    expect ":KILL"
+
+    respond "*" $emulator_escape
+    create_tape "$out/magdmp.tape"
+
+    type ":magfrm\r"
+    respond "?" "KL\r"
+    respond "?" "Y"
+    respond "_" "W"
+    respond "FROM" ".; @ DDT\r"
+    respond "FILE" "@ DDT\r"
+    respond "_" "W"
+    respond "FROM" ".; @ SALV\r"
+    respond "FILE" "@ SALV\r"
+    respond "_" "W"
+    respond "FROM" ".; @ DSKDMP\r"
+    respond "FILE" "@ DSKDMP\r"
+    respond "_" "Q"
+    expect ":KILL"
+}
+
+proc update_microcode {} {
+}
+
+proc clib_switches {} {
+    ### UFA or FIX?!?  Probably the latter.
+    respond "with ^C" "\003"
+}
+
+proc patch_lisp {} {
+    respond "*" ":job lisp\r"
+    respond "*" ":load .; @ lisp\r"
+    respond "*" "33777//\031"
+    respond "*" "\033q\033,777777\033\033z"
+    respond "*" "pitele+13/"
+    respond "FSC" "push p,b\n"
+    respond "FSC" "jrst patch\r"
+    respond "\n" "patch/"
+    respond "0" "move b,echocc\n"
+    respond "0" "add b,ticc\n"
+    respond "0" "dpb b,.+3\n"
+    respond "0" "pop p,b\n"
+    respond "0" "jrst pitele+15\n"
+    respond "0" "331000,,a\r"
+    respond "\n" "\033y"
+    respond " " "dsk0:.;@ lisp\r"
+    respond "*" ":kill\r"
+}
+
+proc translate_diagnostics {} {
+}
+
+proc patch_clib_16 {} {
+}
diff --git a/build/pdp10-ka/boot b/build/pdp10-ka/boot
index 9e27cf22..9ffc2aa0 100644
--- a/build/pdp10-ka/boot
+++ b/build/pdp10-ka/boot
@@ -1,7 +1,11 @@
 set console wru=034
 set cpu its
 set cpu 512k
-set pd off
+dis rpa
+dis rpb
+dis tua
+dis fha
+dis dpb
 at ptr bin/ka10/boot/dskdmp.rim
 at mta0 out/pdp10-ka/minsrc.tape
 at dpa0 out/pdp10-ka/rp03.2
diff --git a/build/pdp10-ka/boot2 b/build/pdp10-ka/boot2
index bfe254d8..1475a3f3 100644
--- a/build/pdp10-ka/boot2
+++ b/build/pdp10-ka/boot2
@@ -3,7 +3,11 @@ set cpu its
 set cpu 1024k
 set cpu mpx
 set cpu ten11
-set pd off
+dis rpa
+dis rpb
+dis tua
+dis fha
+dis dpb
 at ptr bin/ka10/boot/dskdmp.rim
 at mta0 out/pdp10-ka/sources.tape
 set mta mpx=7
diff --git a/build/pdp10-ka/init b/build/pdp10-ka/init
index f0d0fa1d..6912bedd 100644
--- a/build/pdp10-ka/init
+++ b/build/pdp10-ka/init
@@ -1,6 +1,11 @@
 set console wru=034
 set cpu its
 set cpu 512k
+dis rpa
+dis rpb
+dis tua
+dis fha
+dis dpb
 at mta0 out/pdp10-ka/magdmp.tap
 at mta5 out/pdp10-ka/ka-minsys.tape
 at dpa0 out/pdp10-ka/rp03.2
diff --git a/build/pdp10-ka/run b/build/pdp10-ka/run
index 37f664c2..1e1707d6 100644
--- a/build/pdp10-ka/run
+++ b/build/pdp10-ka/run
@@ -3,6 +3,11 @@ set cpu its
 set cpu 1024k
 set cpu idle
 set cpu mpx
+dis rpa
+dis rpb
+dis tua
+dis fha
+dis dpb
 set pd enabled
 set pd on
 set dpy enabled
diff --git a/build/pdp10-kl/boot b/build/pdp10-kl/boot
new file mode 100644
index 00000000..7806c85c
--- /dev/null
+++ b/build/pdp10-kl/boot
@@ -0,0 +1,8 @@
+set console wru=034
+set cpu its
+set cpu 512k
+set pd off
+at ptr bin/kl10/boot/dskdmp.rim
+at mta0 out/pdp10-kl/minsrc.tape
+at rpa0 out/pdp10-kl/rp04.1
+b ptr
diff --git a/build/pdp10-kl/boot2 b/build/pdp10-kl/boot2
new file mode 100644
index 00000000..71866099
--- /dev/null
+++ b/build/pdp10-kl/boot2
@@ -0,0 +1,8 @@
+set console wru=034
+set cpu its
+set cpu 512k
+set pd off
+at ptr bin/kl10/boot/dskdmp.rim
+at mta0 out/pdp10-kl/sources.tape
+at rpa0 out/pdp10-kl/rp04.1
+b ptr
diff --git a/build/pdp10-kl/build.tcl b/build/pdp10-kl/build.tcl
new file mode 100644
index 00000000..f035e4db
--- /dev/null
+++ b/build/pdp10-kl/build.tcl
@@ -0,0 +1,60 @@
+set build [pwd]/build
+set out "out/$env(EMULATOR)"
+set emulator_escape "\034"
+
+proc start_salv {} {
+    uplevel #0 {spawn ./tools/sims/BIN/pdp10-ka build/pdp10-kl/init}
+    setup_timeout
+    respond "MAGDMP\r\n" "l\033ddt\r"
+    respond "\n" "t\033salv bin\r"
+}
+
+proc start_dskdmp args {
+    quit_emulator
+    set ini ""
+    if {[llength $args] == 1} {
+        set ini [lindex $args 0]
+    } {
+        set ini "build/pdp10-kl/boot2"
+    }
+    set foo "spawn ./tools/sims/BIN/pdp10-ka $ini"
+    uplevel #0 $foo
+    setup_timeout
+}
+
+proc mount_tape {file} {
+    respond "sim>" "at mta0 $file\r"
+    respond "sim>" "c\r"
+    expect -timeout 2 "BUGPC/" {
+        type "\033P"
+    } timeout {
+	;
+    }
+}
+
+proc create_tape {file} {
+    respond "sim>" "at mta0 $file\r"
+    respond "sim>" "c\r"
+    expect -timeout 2 "BUGPC/" {
+        type "\033P"
+    } timeout {
+	;
+    }
+}
+
+proc quit_emulator {} {
+    respond "sim>" "q\r"
+    expect eof
+}
+
+proc initialize_comsat {} {
+    # commented out because you cannot run COMSAT initialization without network
+    # support
+    #respond "*" ":job comsat\r"
+    #respond "*" ":load .mail.;comsat launch\r"
+    #respond "*" "debug/-1\r"
+    #type "mfinit\033g"
+}
+
+source build/kl10/include.tcl
+source build/build.tcl
diff --git a/build/pdp10-kl/init b/build/pdp10-kl/init
new file mode 100644
index 00000000..f02a73a8
--- /dev/null
+++ b/build/pdp10-kl/init
@@ -0,0 +1,8 @@
+set console wru=034
+set cpu its
+set cpu 512k
+at mta0 out/pdp10-kl/kl-magdmp.tap
+at mta5 out/pdp10-kl/kl-minsys.tape
+set rpa rp04
+at rpa0 out/pdp10-kl/rp04.1
+b mta0
diff --git a/build/pdp10-kl/run b/build/pdp10-kl/run
new file mode 100644
index 00000000..500b9e85
--- /dev/null
+++ b/build/pdp10-kl/run
@@ -0,0 +1,9 @@
+set console wru=034
+set cpu its
+set cpu 512k
+at ptr bin/kl10/boot/dskdmp.rim
+set rpa rp04
+at rpa0 out/pdp10-kl/rp04.0
+at rpa1 out/pdp10-kl/rp04.1
+at rpa2 out/pdp10-kl/rp04.2
+b ptr
diff --git a/build/pdp10-kl/start b/build/pdp10-kl/start
new file mode 100755
index 00000000..1760196e
--- /dev/null
+++ b/build/pdp10-kl/start
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+TVCON=${TVCON:--2}
+
+EXIT=:
+trap "" QUIT INT TERM
+
+started() {
+    EXIT="$EXIT;stop $1 $2"
+    trap "$EXIT" EXIT
+    echo "$1 started, pid $2"
+}
+
+stop() {
+    echo -n "Stopping $1... "
+    kill "$2" 2> /dev/null
+    sleep 2
+    kill -9 "$2" 2> /dev/null
+    echo "OK"
+}
+
+gt40() {
+    (sleep 3; tools/simh/BIN/pdp11 build/pdp10-ka/gt40 >gt40.log 2>&1) &
+    started GT40 "$!"
+}
+
+tv11() {
+    (sleep 3; tools/tv11/tv11 -p 10011 localhost >tv11.log 2>&1) &
+    started TV-11 "$!"
+}
+
+tvcon() {
+    (sleep 4; tools/tv11/tvcon/tvcon $TVCON localhost >tvcon.log 2>&1) &
+    started "TV-console" "$!"
+}
+
+while test -n "$1"; do
+    "$1"
+    shift
+done
+
+tools/sims/BIN/pdp10-ka build/pdp10-ka/run
+exit 0