diff --git a/.gitattributes b/.gitattributes
index d659b707699..855e683b873 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -361,6 +361,20 @@ src/emu/bus/isbx/compis_fdc.c svneol=native#text/plain
 src/emu/bus/isbx/compis_fdc.h svneol=native#text/plain
 src/emu/bus/isbx/isbx.c svneol=native#text/plain
 src/emu/bus/isbx/isbx.h svneol=native#text/plain
+src/emu/bus/s100/dj2db.c svneol=native#text/plain
+src/emu/bus/s100/dj2db.h svneol=native#text/plain
+src/emu/bus/s100/djdma.c svneol=native#text/plain
+src/emu/bus/s100/djdma.h svneol=native#text/plain
+src/emu/bus/s100/mm65k16s.c svneol=native#text/plain
+src/emu/bus/s100/mm65k16s.h svneol=native#text/plain
+src/emu/bus/s100/nsmdsa.c svneol=native#text/plain
+src/emu/bus/s100/nsmdsa.h svneol=native#text/plain
+src/emu/bus/s100/nsmdsad.c svneol=native#text/plain
+src/emu/bus/s100/nsmdsad.h svneol=native#text/plain
+src/emu/bus/s100/s100.c svneol=native#text/plain
+src/emu/bus/s100/s100.h svneol=native#text/plain
+src/emu/bus/s100/wunderbus.c svneol=native#text/plain
+src/emu/bus/s100/wunderbus.h svneol=native#text/plain
 src/emu/cheat.c svneol=native#text/plain
 src/emu/cheat.h svneol=native#text/plain
 src/emu/clifront.c svneol=native#text/plain
@@ -7939,20 +7953,6 @@ src/mess/machine/rm380z.c svneol=native#text/plain
 src/mess/machine/rmnimbus.c svneol=native#text/plain
 src/mess/machine/rx01.c svneol=native#text/plain
 src/mess/machine/rx01.h svneol=native#text/plain
-src/mess/machine/s100.c svneol=native#text/plain
-src/mess/machine/s100.h svneol=native#text/plain
-src/mess/machine/s100_dj2db.c svneol=native#text/plain
-src/mess/machine/s100_dj2db.h svneol=native#text/plain
-src/mess/machine/s100_djdma.c svneol=native#text/plain
-src/mess/machine/s100_djdma.h svneol=native#text/plain
-src/mess/machine/s100_mm65k16s.c svneol=native#text/plain
-src/mess/machine/s100_mm65k16s.h svneol=native#text/plain
-src/mess/machine/s100_nsmdsa.c svneol=native#text/plain
-src/mess/machine/s100_nsmdsa.h svneol=native#text/plain
-src/mess/machine/s100_nsmdsad.c svneol=native#text/plain
-src/mess/machine/s100_nsmdsad.h svneol=native#text/plain
-src/mess/machine/s100_wunderbus.c svneol=native#text/plain
-src/mess/machine/s100_wunderbus.h svneol=native#text/plain
 src/mess/machine/s1410.c svneol=native#text/plain
 src/mess/machine/s1410.h svneol=native#text/plain
 src/mess/machine/s3c44b0.c svneol=native#text/plain
diff --git a/src/emu/bus/bus.mak b/src/emu/bus/bus.mak
index b86c561e797..71667261b16 100644
--- a/src/emu/bus/bus.mak
+++ b/src/emu/bus/bus.mak
@@ -23,3 +23,19 @@ ifneq ($(filter ISBX,$(BUSES)),)
 BUSOBJS += $(BUSOBJ)/isbx/isbx.o
 BUSOBJS += $(BUSOBJ)/isbx/compis_fdc.o
 endif
+
+
+#-------------------------------------------------
+#
+#@src/emu/bus/isbx.h,BUSES += S100
+#-------------------------------------------------
+
+ifneq ($(filter S100,$(BUSES)),)
+BUSOBJS += $(BUSOBJ)/s100/s100.o
+BUSOBJS += $(BUSOBJ)/s100/dj2db.o
+BUSOBJS += $(BUSOBJ)/s100/djdma.o
+BUSOBJS += $(BUSOBJ)/s100/mm65k16s.o
+BUSOBJS += $(BUSOBJ)/s100/nsmdsa.o
+BUSOBJS += $(BUSOBJ)/s100/nsmdsad.o
+BUSOBJS += $(BUSOBJ)/s100/wunderbus.o
+endif
diff --git a/src/mess/machine/s100_dj2db.c b/src/emu/bus/s100/dj2db.c
similarity index 99%
rename from src/mess/machine/s100_dj2db.c
rename to src/emu/bus/s100/dj2db.c
index eb370204eb3..03ebb1afdb1 100644
--- a/src/mess/machine/s100_dj2db.c
+++ b/src/emu/bus/s100/dj2db.c
@@ -17,7 +17,7 @@
 
 */
 
-#include "s100_dj2db.h"
+#include "dj2db.h"
 
 
 
diff --git a/src/mess/machine/s100_dj2db.h b/src/emu/bus/s100/dj2db.h
similarity index 98%
rename from src/mess/machine/s100_dj2db.h
rename to src/emu/bus/s100/dj2db.h
index aae4246d8bf..ce444f11a22 100644
--- a/src/mess/machine/s100_dj2db.h
+++ b/src/emu/bus/s100/dj2db.h
@@ -14,9 +14,8 @@
 #ifndef __S100_DJ2DB__
 #define __S100_DJ2DB__
 
-
 #include "emu.h"
-#include "machine/s100.h"
+#include "s100.h"
 #include "machine/com8116.h"
 #include "machine/wd_fdc.h"
 
diff --git a/src/mess/machine/s100_djdma.c b/src/emu/bus/s100/djdma.c
similarity index 99%
rename from src/mess/machine/s100_djdma.c
rename to src/emu/bus/s100/djdma.c
index 286f8f7fa70..6a8b4403f26 100644
--- a/src/mess/machine/s100_djdma.c
+++ b/src/emu/bus/s100/djdma.c
@@ -9,7 +9,7 @@
 
 **********************************************************************/
 
-#include "s100_djdma.h"
+#include "djdma.h"
 
 
 
diff --git a/src/mess/machine/s100_djdma.h b/src/emu/bus/s100/djdma.h
similarity index 97%
rename from src/mess/machine/s100_djdma.h
rename to src/emu/bus/s100/djdma.h
index c14012009fb..2f36218bb5c 100644
--- a/src/mess/machine/s100_djdma.h
+++ b/src/emu/bus/s100/djdma.h
@@ -14,10 +14,9 @@
 #ifndef __S100_DJDMA__
 #define __S100_DJDMA__
 
-
 #include "emu.h"
+#include "s100.h"
 #include "cpu/z80/z80.h"
-#include "machine/s100.h"
 
 
 
diff --git a/src/mess/machine/s100_mm65k16s.c b/src/emu/bus/s100/mm65k16s.c
similarity index 99%
rename from src/mess/machine/s100_mm65k16s.c
rename to src/emu/bus/s100/mm65k16s.c
index 794535202af..6bc4ab13a84 100644
--- a/src/mess/machine/s100_mm65k16s.c
+++ b/src/emu/bus/s100/mm65k16s.c
@@ -9,7 +9,7 @@
 
 **********************************************************************/
 
-#include "s100_mm65k16s.h"
+#include "mm65k16s.h"
 
 
 
diff --git a/src/mess/machine/s100_mm65k16s.h b/src/emu/bus/s100/mm65k16s.h
similarity index 98%
rename from src/mess/machine/s100_mm65k16s.h
rename to src/emu/bus/s100/mm65k16s.h
index 90bb39f1ace..54928dd30c4 100644
--- a/src/mess/machine/s100_mm65k16s.h
+++ b/src/emu/bus/s100/mm65k16s.h
@@ -15,7 +15,7 @@
 #define __S100_MM65K16S__
 
 #include "emu.h"
-#include "machine/s100.h"
+#include "s100.h"
 
 
 
diff --git a/src/mess/machine/s100_nsmdsa.c b/src/emu/bus/s100/nsmdsa.c
similarity index 99%
rename from src/mess/machine/s100_nsmdsa.c
rename to src/emu/bus/s100/nsmdsa.c
index 9d028548568..ecbc9668fa9 100644
--- a/src/mess/machine/s100_nsmdsa.c
+++ b/src/emu/bus/s100/nsmdsa.c
@@ -9,7 +9,7 @@
 
 **********************************************************************/
 
-#include "s100_nsmdsa.h"
+#include "nsmdsa.h"
 
 
 
diff --git a/src/mess/machine/s100_nsmdsa.h b/src/emu/bus/s100/nsmdsa.h
similarity index 98%
rename from src/mess/machine/s100_nsmdsa.h
rename to src/emu/bus/s100/nsmdsa.h
index 720979657aa..16393b1fb74 100644
--- a/src/mess/machine/s100_nsmdsa.h
+++ b/src/emu/bus/s100/nsmdsa.h
@@ -15,8 +15,8 @@
 #define __S100_MDS_A__
 
 #include "emu.h"
+#include "s100.h"
 #include "imagedev/floppy.h"
-#include "machine/s100.h"
 
 
 
diff --git a/src/mess/machine/s100_nsmdsad.c b/src/emu/bus/s100/nsmdsad.c
similarity index 99%
rename from src/mess/machine/s100_nsmdsad.c
rename to src/emu/bus/s100/nsmdsad.c
index 637fafd8fed..00aa0b47cbd 100644
--- a/src/mess/machine/s100_nsmdsad.c
+++ b/src/emu/bus/s100/nsmdsad.c
@@ -9,7 +9,7 @@
 
 **********************************************************************/
 
-#include "s100_nsmdsad.h"
+#include "nsmdsad.h"
 
 
 
diff --git a/src/mess/machine/s100_nsmdsad.h b/src/emu/bus/s100/nsmdsad.h
similarity index 98%
rename from src/mess/machine/s100_nsmdsad.h
rename to src/emu/bus/s100/nsmdsad.h
index 519199b297a..a7692fd61df 100644
--- a/src/mess/machine/s100_nsmdsad.h
+++ b/src/emu/bus/s100/nsmdsad.h
@@ -15,8 +15,8 @@
 #define __S100_MDS_AD__
 
 #include "emu.h"
+#include "s100.h"
 #include "imagedev/floppy.h"
-#include "machine/s100.h"
 
 
 
diff --git a/src/mess/machine/s100.c b/src/emu/bus/s100/s100.c
similarity index 99%
rename from src/mess/machine/s100.c
rename to src/emu/bus/s100/s100.c
index 8f2475d8286..a16fd7e08ee 100644
--- a/src/mess/machine/s100.c
+++ b/src/emu/bus/s100/s100.c
@@ -11,7 +11,7 @@
 
 #include "emu.h"
 #include "emuopts.h"
-#include "machine/s100.h"
+#include "s100.h"
 
 
 //**************************************************************************
diff --git a/src/mess/machine/s100.h b/src/emu/bus/s100/s100.h
similarity index 98%
rename from src/mess/machine/s100.h
rename to src/emu/bus/s100/s100.h
index 85115b75250..f213cc15289 100644
--- a/src/mess/machine/s100.h
+++ b/src/emu/bus/s100/s100.h
@@ -273,4 +273,14 @@ public:
 	device_s100_card_interface *m_next;
 };
 
+
+// slot devices
+#include "dj2db.h"
+#include "djdma.h"
+#include "mm65k16s.h"
+#include "nsmdsa.h"
+#include "nsmdsad.h"
+#include "wunderbus.h"
+
+
 #endif
diff --git a/src/mess/machine/s100_wunderbus.c b/src/emu/bus/s100/wunderbus.c
similarity index 99%
rename from src/mess/machine/s100_wunderbus.c
rename to src/emu/bus/s100/wunderbus.c
index 285c47d51f5..7e0e3a796fd 100644
--- a/src/mess/machine/s100_wunderbus.c
+++ b/src/emu/bus/s100/wunderbus.c
@@ -9,7 +9,7 @@
 
 **********************************************************************/
 
-#include "s100_wunderbus.h"
+#include "wunderbus.h"
 
 
 
diff --git a/src/mess/machine/s100_wunderbus.h b/src/emu/bus/s100/wunderbus.h
similarity index 98%
rename from src/mess/machine/s100_wunderbus.h
rename to src/emu/bus/s100/wunderbus.h
index 7a15336a0af..bb8adcc25bc 100644
--- a/src/mess/machine/s100_wunderbus.h
+++ b/src/emu/bus/s100/wunderbus.h
@@ -15,9 +15,9 @@
 #define __S100_WUNDERBUS__
 
 #include "emu.h"
+#include "s100.h"
 #include "machine/ins8250.h"
 #include "machine/pic8259.h"
-#include "machine/s100.h"
 #include "machine/serial.h"
 #include "machine/upd1990a.h"
 
diff --git a/src/emu/emu.mak b/src/emu/emu.mak
index 9a420e00329..c19b76774e4 100644
--- a/src/emu/emu.mak
+++ b/src/emu/emu.mak
@@ -29,6 +29,7 @@ OBJDIRS += \
 	$(EMUOBJ)/audio \
 	$(EMUOBJ)/bus \
 	$(EMUOBJ)/bus/isbx \
+	$(EMUOBJ)/bus/s100 \
 	$(EMUOBJ)/drivers \
 	$(EMUOBJ)/machine \
 	$(EMUOBJ)/layout \
diff --git a/src/mess/drivers/horizon.c b/src/mess/drivers/horizon.c
index 044bd9d0267..76947656fd4 100644
--- a/src/mess/drivers/horizon.c
+++ b/src/mess/drivers/horizon.c
@@ -31,12 +31,10 @@
 */
 
 #include "emu.h"
+#include "bus/s100/s100.h"
 #include "cpu/z80/z80.h"
 #include "machine/i8251.h"
 #include "machine/serial.h"
-#include "machine/s100.h"
-#include "machine/s100_nsmdsa.h"
-#include "machine/s100_nsmdsad.h"
 
 #define Z80_TAG         "z80"
 #define I8251_L_TAG     "3a"
diff --git a/src/mess/includes/mpz80.h b/src/mess/includes/mpz80.h
index ebcacfe173a..1f53dbf40b0 100644
--- a/src/mess/includes/mpz80.h
+++ b/src/mess/includes/mpz80.h
@@ -5,15 +5,10 @@
 #ifndef __MPZ80__
 #define __MPZ80__
 
-
 #include "emu.h"
+#include "bus/s100/s100.h"
 #include "cpu/z80/z80.h"
 #include "machine/ram.h"
-#include "machine/s100.h"
-#include "machine/s100_dj2db.h"
-#include "machine/s100_djdma.h"
-#include "machine/s100_mm65k16s.h"
-#include "machine/s100_wunderbus.h"
 
 #define Z80_TAG         "17a"
 #define AM9512_TAG      "17d"
diff --git a/src/mess/includes/xor100.h b/src/mess/includes/xor100.h
index 0bf27573f94..02dab8a4046 100644
--- a/src/mess/includes/xor100.h
+++ b/src/mess/includes/xor100.h
@@ -6,13 +6,13 @@
 #define __XOR100__
 
 #include "emu.h"
+#include "bus/s100/s100.h"
 #include "cpu/z80/z80.h"
 #include "machine/ram.h"
 #include "machine/com8116.h"
 #include "machine/ctronics.h"
 #include "machine/i8255.h"
 #include "machine/i8251.h"
-#include "machine/s100.h"
 #include "machine/serial.h"
 #include "machine/wd_fdc.h"
 #include "machine/z80ctc.h"
diff --git a/src/mess/mess.mak b/src/mess/mess.mak
index ceda2cce865..5903c746ee6 100644
--- a/src/mess/mess.mak
+++ b/src/mess/mess.mak
@@ -477,6 +477,7 @@ MACHINES += PCCARD
 #-------------------------------------------------
 
 BUSES += ISBX
+BUSES += S100
 
 #-------------------------------------------------
 # this is the list of driver libraries that
@@ -780,7 +781,6 @@ $(MESSOBJ)/shared.a: \
 	$(MESS_MACHINE)/null_modem.o\
 	$(MESS_MACHINE)/pc_kbdc.o   \
 	$(MESS_MACHINE)/pc_lpt.o    \
-	$(MESS_MACHINE)/s100.o      \
 	$(MESS_MACHINE)/sa1403d.o   \
 	$(MESS_MACHINE)/sed1200.o   \
 	$(MESS_MACHINE)/serial.o    \
@@ -1630,10 +1630,6 @@ $(MESSOBJ)/mitsubishi.a:        \
 
 $(MESSOBJ)/morrow.a:            \
 	$(MESS_DRIVERS)/mpz80.o     \
-	$(MESS_MACHINE)/s100_dj2db.o\
-	$(MESS_MACHINE)/s100_djdma.o\
-	$(MESS_MACHINE)/s100_mm65k16s.o     \
-	$(MESS_MACHINE)/s100_wunderbus.o    \
 
 $(MESSOBJ)/mos.a:               \
 	$(MESS_DRIVERS)/kim1.o      \
@@ -1767,8 +1763,6 @@ $(MESSOBJ)/nokia.a:             \
 
 $(MESSOBJ)/northstar.a:         \
 	$(MESS_DRIVERS)/horizon.o   \
-	$(MESS_MACHINE)/s100_nsmdsa.o \
-	$(MESS_MACHINE)/s100_nsmdsad.o \
 
 $(MESSOBJ)/novag.a:             \
 	$(MESS_DRIVERS)/mk1.o       \