diff --git a/README.md b/README.md
index 07e0c19..1b551eb 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ If the emulator is run with no options, it prints a usage screen:
 E:\DEC> tu58em
 ERROR: no units were specified
 FATAL: illegal command line
-  tu58 tape emulator v1.4j
+  tu58 tape emulator v1.4k
   Usage: ./tu58em [-options] -[rwci] file1 ... -[rwci] file7
   Options: -V | --version            output version string
            -v | --verbose            enable verbose output to terminal
diff --git a/cygwin1.dll b/cygwin1.dll
index 03ff8d9..7667961 100644
Binary files a/cygwin1.dll and b/cygwin1.dll differ
diff --git a/main.c b/main.c
index 61a94f4..dec72df 100644
--- a/main.c
+++ b/main.c
@@ -39,6 +39,8 @@
 // v1.4j - 01 Nov 2014 - donorth - Change 'int' to 'long' where possible.
 //                                 Only use char/short/long types, not int.
 //                                 Fix source for ubuntu linux 12.04 (time structs)
+// v1.4k - 11 Jun 2015 - donorth - Integrate Mark Blair's changes for MacOSX compilation
+//                               - No functionality changes on other platforms
 //
 
 
@@ -49,7 +51,7 @@
 static char copyright[] = "(C) 2005-2014 Don North <ak6dn" "@" "mindspring.com>, " \
                           "(C) 1984 Dan Ts'o <Rockefeller University>";
 
-static char version[] = "tu58 tape emulator v1.4j";
+static char version[] = "tu58 tape emulator v1.4k";
 
 static char port[32] = "1"; // default port number (COM1, /dev/ttyS0)
 static long speed = 9600; // default line speed
diff --git a/makefile b/makefile
index 318d95d..90a6ccf 100644
--- a/makefile
+++ b/makefile
@@ -2,11 +2,15 @@
 # tu58em emulator makefile
 #
 
-ifeq ($(comm),win)
+ifeq ($(comm),mac)
+# UNIX comms model, but on a Mac
+PROG = tu58em
+COMM = -UWINCOMM -DMACOSX
+else ifeq ($(comm),win)
 # WINDOWS comms model
 PROG = tu58ew
 COMM = -DWINCOMM
-else
+else # ifeq ($(comm),unix)
 # UNIX comms model
 PROG = tu58em
 COMM = -UWINCOMM
@@ -16,7 +20,11 @@ BIN = ../../../../../tools/exe
 
 CC = gcc
 CFLAGS = -I. -O3 -Wall -c $(COMM)
+ifeq ($(comm),mac)
+LFLAGS = -lpthread
+else
 LFLAGS = -lpthread -lrt
+endif
 
 $(PROG) : main.o tu58drive.o file.o serial.o
 	$(CC) -o $@ main.o tu58drive.o file.o serial.o $(LFLAGS)
@@ -27,6 +35,10 @@ all :
 	make --always comm=unix
 	make clean
 
+mac :
+	make --always comm=mac
+	make --clean
+
 installall :
 	make --always comm=win install
 	make clean
@@ -35,7 +47,7 @@ installall :
 
 clean :
 	-rm -f *.o
-	-chmod a-x,ug+w,o-w *.c *.h Makefile
+	-chmod a-x,ug+w,o-w *.c *.h makefile
 	-chmod a+rx $(PROG) $(PROG).exe
 	-chown `whoami` *
 
diff --git a/serial.c b/serial.c
index 89ec73e..f80be1c 100644
--- a/serial.c
+++ b/serial.c
@@ -21,6 +21,12 @@
 #include <winbase.h>
 #endif // WINCOMM
 
+#ifdef MACOSX
+#define IUCLC 0 // Not POSIX
+#define OLCUC 0 // Not POSIX
+#define CBAUD 0 // Not POSIX
+#endif
+
 #include <termios.h>
 
 #define	BUFSIZE	256	// size of serial line buffers (bytes, each way)
diff --git a/tu58drive.c b/tu58drive.c
index 30426dd..0e1cd24 100644
--- a/tu58drive.c
+++ b/tu58drive.c
@@ -20,6 +20,18 @@
 
 #include "tu58.h"
 
+#ifdef MACOSX
+// clock_gettime() is not available under OSX
+#define CLOCK_REALTIME 1
+#include <mach/mach_time.h>
+
+void clock_gettime(int dummy, timespec_t *t) {
+    uint64_t mt;
+    mt = mach_absolute_time();
+    t->tv_sec  = mt / 1000000000;
+    t->tv_nsec = mt % 1000000000;
+}
+#endif
 
 
 // delays for modeling device access
@@ -524,6 +536,12 @@ static void command (int8_t flag)
     char *name= "none";
     uint8_t mode = 0;
 
+    // Avoid uninitialized variable warnings
+    time_start.tv_sec  = 0;
+    time_start.tv_nsec = 0;
+    time_end.tv_sec    = 0;
+    time_end.tv_nsec   = 0;
+
     pk.flag = flag;
     pk.length = devrxget();
 
diff --git a/tu58em.exe b/tu58em.exe
index 244018d..0f65292 100644
Binary files a/tu58em.exe and b/tu58em.exe differ
diff --git a/tu58ew.exe b/tu58ew.exe
index c2ebe1d..4edf33a 100644
Binary files a/tu58ew.exe and b/tu58ew.exe differ