diff --git a/Visual Studio Projects/AltairZ80.vcproj b/Visual Studio Projects/AltairZ80.vcproj
index b3372a62..c1205f89 100644
--- a/Visual Studio Projects/AltairZ80.vcproj	
+++ b/Visual Studio Projects/AltairZ80.vcproj	
@@ -320,6 +320,10 @@
 				RelativePath="..\AltairZ80\s100_mdriveh.c"
 				>
 			</File>
+			<File
+				RelativePath="..\AltairZ80\s100_mdsa.c"
+				>
+			</File>
 			<File
 				RelativePath="..\AltairZ80\s100_mdsad.c"
 				>
diff --git a/descrip.mms b/descrip.mms
index 41f67d47..3bf22901 100644
--- a/descrip.mms
+++ b/descrip.mms
@@ -323,7 +323,8 @@ ALTAIRZ80_SOURCE1 = $(ALTAIRZ80_DIR)ALTAIRZ80_CPU.C,$(ALTAIRZ80_DIR)ALTAIRZ80_CP
                     $(ALTAIRZ80_DIR)FLASHWRITER2.C,$(ALTAIRZ80_DIR)I86_DECODE.C,\
                     $(ALTAIRZ80_DIR)I86_OPS.C,$(ALTAIRZ80_DIR)I86_PRIM_OPS.C,\
                     $(ALTAIRZ80_DIR)I8272.C,$(ALTAIRZ80_DIR)INSNSD.C,\
-                    $(ALTAIRZ80_DIR)MFDC.C,$(ALTAIRZ80_DIR)N8VEM.C,$(ALTAIRZ80_DIR)VFDHD.C
+                    $(ALTAIRZ80_DIR)MFDC.C,$(ALTAIRZ80_DIR)N8VEM.C,\
+                    $(ALTAIRZ80_DIR)S100_MDSA.C,$(ALTAIRZ80_DIR)VFDHD.C
 ALTAIRZ80_LIB2 = $(LIB_DIR)ALTAIRZ80L2-$(ARCH).OLB
 ALTAIRZ80_SOURCE2 = $(ALTAIRZ80_DIR)S100_DISK1A.C,$(ALTAIRZ80_DIR)S100_DISK2.C,\
                     $(ALTAIRZ80_DIR)S100_FIF.C,$(ALTAIRZ80_DIR)S100_MDRIVEH.C,\