--- a/partition_map.c
+++ b/partition_map.c
@@ -25,6 +25,11 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 
  */
 
+//
+// Defines
+//
+// #define TEST_COMPUTE
+
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -36,6 +41,10 @@
 #include <sys/ioctl.h>
 #include "kernel-defs.h"
 #include <sys/stat.h>
+#ifdef TEST_COMPUTE
+#include <linux/fs.h>
+#endif
+
 #endif
 
 #include "partition_map.h"
@@ -45,10 +54,6 @@
 #include "errors.h"
 
 
-//
-// Defines
-//
-// #define TEST_COMPUTE
 
 
 //
@@ -666,7 +671,7 @@
     loff_t pos;
 #endif
     char* data;
-    unsigned long l, r, x;
+    unsigned long long l, r, x;
     int valid;
 
 #ifdef TEST_COMPUTE
@@ -720,9 +725,11 @@
 	    } else {
 		r = r * 2;
 	    }
-	    if (r >= (1024*1024*1024)) {
-		break;
-	    }
+// 	    There's no explanation for this, but I suspect the author was trying to
+// 	    prevent going over the 32 bit size
+//	    if (r >= (1024*1024*1024*2)) {
+//		break;
+//	    }
 	}
 	// binary search for end
 	while (l <= r) {
@@ -740,11 +747,17 @@
 	if (valid != 0) {
 	    x = x + 1;
 	}
-	// printf("size in blocks = %d\n", x);
+#ifdef TEST_COMPUTE
+	printf("size in blocks = %d\n", x);
+#endif
 	free(data);
     }
+    
+    // Add a warning just in case...
+    if(x > 0x80000000)
+    	printf("Warning: Large disks may not work with this tool!\n");
 
-    return x;
+    return (unsigned long) x;
 }