diff --git a/sdtape.cpp b/sdtape.cpp
index 1564d5a..08e727f 100644
--- a/sdtape.cpp
+++ b/sdtape.cpp
@@ -12,10 +12,14 @@
 
 static File file, dir;
 
-void sdtape::start(const char *programs)
+bool sdtape::start(const char *programs)
 {
 	dir = DISK.open(programs);
+	if (!dir)
+		return false;
+
 	_pos = _len = 0;
+	return true;
 }
 
 void sdtape::stop()
diff --git a/sdtape.h b/sdtape.h
index b8794b5..5ba9aa0 100644
--- a/sdtape.h
+++ b/sdtape.h
@@ -6,16 +6,14 @@ public:
 	const char *advance();
 	const char *rewind();
 
-	void start(const char *);
+	bool start(const char *);
 	void stop();
 	
-	sdtape(): _pos(0), _len(0) {}
-
 	uint8_t read() { return _buf[_pos++]; }
 	bool more();
 
 private:
-	unsigned int _pos, _len;
+	unsigned _pos, _len;
 	uint8_t _buf[128];
 };
 #endif