Splitting by hard sectors works, up to a point; we can correctly decode (with

CRC checking!) most of the Zilog MCS disk. However, we're still stumped by the
extra index hole.

lib/fluxmap.h

@@ -59,6 +59,9 @@ public:
     void rewind()
     { _cursor = 0; }
 
+    size_t tell() const
+    { return _cursor; }
+
     int read(unsigned& ticks);
     int readPulse(unsigned& ticks);