diff --git a/libs/ardour/ardour/disk_io.h b/libs/ardour/ardour/disk_io.h
new file mode 100644
index 0000000000..4819b63293
--- /dev/null
+++ b/libs/ardour/ardour/disk_io.h
@@ -0,0 +1,160 @@
+/*
+    Copyright (C) 2009-2016 Paul Davis
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#ifndef __ardour_disk_io_h__
+#define __ardour_disk_io_h__
+
+#include <vector>
+#include <string>
+#include <exception>
+
+#include "ardour/processor.h"
+
+namespace ARDOUR {
+
+class Session;
+class Route;
+
+class LIBARDOUR_API DiskIOProcessor : public Processor
+{
+  public:
+	static const std::string state_node_name;
+
+	DiskIOProcessor(Session&, const std::string& name);
+
+	void run (BufferSet& /*bufs*/, framepos_t /*start_frame*/, framepos_t /*end_frame*/, double speed, pframes_t /*nframes*/, bool /*result_required*/) {}
+	void silence (framecnt_t /*nframes*/, framepos_t /*start_frame*/) {}
+
+	bool configure_io (ChanCount in, ChanCount out);
+	bool can_support_io_configuration (const ChanCount& in, ChanCount& out) = 0;
+	ChanCount input_streams () const { return _configured_input; }
+	ChanCount output_streams() const { return _configured_output; }
+
+	virtual void realtime_handle_transport_stopped () {}
+	virtual void realtime_locate () {}
+
+	/* note: derived classes should implement state(), NOT get_state(), to allow
+	   us to merge C++ inheritance and XML lack-of-inheritance reasonably
+	   smoothly.
+	 */
+
+	virtual XMLNode& state (bool full);
+	XMLNode& get_state (void);
+	int set_state (const XMLNode&, int version);
+
+	static framecnt_t disk_read_frames() { return disk_read_chunk_frames; }
+	static framecnt_t disk_write_frames() { return disk_write_chunk_frames; }
+	static void set_disk_read_chunk_frames (framecnt_t n) { disk_read_chunk_frames = n; }
+	static void set_disk_write_chunk_frames (framecnt_t n) { disk_write_chunk_frames = n; }
+	static framecnt_t default_disk_read_chunk_frames ();
+	static framecnt_t default_disk_write_chunk_frames ();
+
+	static void set_buffering_parameters (BufferingPreset bp);
+
+protected:
+	static framecnt_t disk_read_chunk_frames;
+	static framecnt_t disk_write_chunk_frames;
+
+	uint32_t i_am_the_modifier;
+
+	Track*       _track;
+	ChanCount    _n_channels;
+
+	double       _visible_speed;
+	double       _actual_speed;
+	/* items needed for speed change logic */
+	bool         _buffer_reallocation_required;
+	bool         _seek_required;
+	bool         _slaved;
+	Location*     loop_location;
+	double        _speed;
+	double        _target_speed;
+	bool          in_set_state;
+
+	Glib::Threads::Mutex state_lock;
+	Flag _flags;
+};
+
+class LIBARDOUR_API DiskReader : public DiskIOProcessor
+{
+  public:
+	DiskReader (Session&, std::string const & name);
+	~DiskReader ();
+
+  private:
+	boost::shared_ptr<Playlist> _playlist;
+
+	framepos_t    overwrite_frame;
+	off_t         overwrite_offset;
+	bool          _pending_overwrite;
+	bool          overwrite_queued;
+	IOChange      input_change_pending;
+	framecnt_t    wrap_buffer_size;
+	framecnt_t    speed_buffer_size;
+
+	double        _speed;
+	double        _target_speed;
+
+	/** The next frame position that we should be reading from in our playlist */
+	framepos_t     file_frame;
+	framepos_t     playback_sample;
+
+	PBD::ScopedConnectionList playlist_connections;
+	PBD::ScopedConnection ic_connection;
+};
+
+class LIBARDOUR_API DiskWriter : public DiskIOProcessor
+{
+  public:
+	DiskWriter (Session&, std::string const & name);
+	~DiskWriter ();
+
+  private:
+	std::vector<CaptureInfo*> capture_info;
+	mutable Glib::Threads::Mutex capture_info_lock;
+
+	double       _visible_speed;
+	double       _actual_speed;
+	/* items needed for speed change logic */
+	bool         _buffer_reallocation_required;
+	bool         _seek_required;
+
+	/** Start of currently running capture in session frames */
+	framepos_t    capture_start_frame;
+	framecnt_t    capture_captured;
+	bool          was_recording;
+	framecnt_t    adjust_capture_position;
+	framecnt_t   _capture_offset;
+	framepos_t    first_recordable_frame;
+	framepos_t    last_recordable_frame;
+	int           last_possibly_recording;
+	AlignStyle   _alignment_style;
+	AlignChoice  _alignment_choice;
+	framecnt_t    wrap_buffer_size;
+	framecnt_t    speed_buffer_size;
+
+	std::string   _write_source_name;
+
+	PBD::ScopedConnection ic_connection;
+};
+
+
+} // namespace ARDOUR
+
+#endif /* __ardour_processor_h__ */