diff --git a/CMakeLists.txt b/CMakeLists.txt
index ece5d139e4..ada2e6b4c4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -148,8 +148,6 @@ set(BOUT_SOURCES
   ./include/bout/operatorstencil.hxx
   ./include/bout/options.hxx
   ./include/bout/options_io.hxx
-  ./include/bout/options_netcdf.hxx
-  ./include/bout/options_adios.hxx
   ./include/bout/optionsreader.hxx
   ./include/bout/output.hxx
   ./include/bout/output_bout_types.hxx
@@ -344,7 +342,9 @@ set(BOUT_SOURCES
   ./src/sys/options/options_ini.hxx
   ./src/sys/options/options_io.cxx
   ./src/sys/options/options_netcdf.cxx
+  ./src/sys/options/options_netcdf.hxx
   ./src/sys/options/options_adios.cxx
+  ./src/sys/options/options_adios.hxx
   ./src/sys/optionsreader.cxx
   ./src/sys/output.cxx
   ./src/sys/petsclib.cxx
diff --git a/include/bout/bout.hxx b/include/bout/bout.hxx
index 5e718dde33..d929a19c2f 100644
--- a/include/bout/bout.hxx
+++ b/include/bout/bout.hxx
@@ -2,8 +2,6 @@
  *
  * @mainpage BOUT++
  *
- * @version 3.0
- *
  * @par Description
  * Framework for the solution of partial differential
  * equations, in particular fluid models in plasma physics.
@@ -33,8 +31,8 @@
  *
  **************************************************************************/
 
-#ifndef __BOUT_H__
-#define __BOUT_H__
+#ifndef BOUT_H
+#define BOUT_H
 
 #include "bout/build_config.hxx"
 
@@ -44,7 +42,7 @@
 #include "bout/field3d.hxx"
 #include "bout/globals.hxx"
 #include "bout/mesh.hxx"
-#include "bout/options_netcdf.hxx"
+#include "bout/options_io.hxx"
 #include "bout/output.hxx"
 #include "bout/smoothing.hxx" // Smoothing functions
 #include "bout/solver.hxx"
@@ -206,4 +204,4 @@ private:
  */
 int BoutFinalise(bool write_settings = true);
 
-#endif // __BOUT_H__
+#endif // BOUT_H
diff --git a/include/bout/generic_factory.hxx b/include/bout/generic_factory.hxx
index 3a2a63c94c..f7a0692af8 100644
--- a/include/bout/generic_factory.hxx
+++ b/include/bout/generic_factory.hxx
@@ -1,8 +1,8 @@
 /// Base type for factories
 
 #pragma once
-#ifndef __BOUT_GENERIC_FACTORY_H__
-#define __BOUT_GENERIC_FACTORY_H__
+#ifndef BOUT_GENERIC_FACTORY_H
+#define BOUT_GENERIC_FACTORY_H
 
 #include "bout/boutexception.hxx"
 #include "bout/options.hxx"
@@ -259,4 +259,4 @@ public:
   };
 };
 
-#endif // __BOUT_GENERIC_FACTORY_H__
+#endif // BOUT_GENERIC_FACTORY_H
diff --git a/include/bout/options_adios.hxx b/include/bout/options_adios.hxx
deleted file mode 100644
index 7bbe421247..0000000000
--- a/include/bout/options_adios.hxx
+++ /dev/null
@@ -1,95 +0,0 @@
-
-#pragma once
-
-#ifndef __OPTIONS_ADIOS_H__
-#define __OPTIONS_ADIOS_H__
-
-#include "bout/build_config.hxx"
-#include "bout/options.hxx"
-#include "bout/options_io.hxx"
-
-#if !BOUT_HAS_ADIOS
-
-#include <string>
-
-#include "bout/boutexception.hxx"
-
-namespace bout {
-
-class OptionsADIOS : public OptionsIO {
-public:
-  OptionsADIOS() {}
-  explicit OptionsADIOS(const std::string& filename [[maybe_unused]],
-                        [[maybe_unused]] bout::OptionsIO::FileMode mode =
-                            bout::OptionsIO::FileMode::replace,
-                        [[maybe_unused]] bool singleWriteFile = false) {}
-  OptionsADIOS(const OptionsADIOS&) = delete;
-  OptionsADIOS(OptionsADIOS&&) noexcept = default;
-  ~OptionsADIOS() = default;
-
-  OptionsADIOS& operator=(const OptionsADIOS&) = delete;
-  OptionsADIOS& operator=(OptionsADIOS&&) noexcept = default;
-
-  /// Read options from file
-  Options read() override { throw BoutException("OptionsADIOS not available\n"); }
-
-  /// Write options to file
-  void write([[maybe_unused]] const Options& options,
-             [[maybe_unused]] const std::string& time_dim) override {
-    throw BoutException("OptionsADIOS not available\n");
-  }
-
-  void verifyTimesteps() const override {
-    throw BoutException("OptionsADIOS not available\n");
-  }
-};
-
-} // namespace bout
-
-#else
-
-#include <memory>
-#include <string>
-
-namespace bout {
-
-/// Forward declare ADIOS file type so we don't need to depend
-/// directly on ADIOS
-struct ADIOSStream;
-
-class OptionsADIOS : public OptionsIO {
-public:
-  // Constructors need to be defined in implementation due to forward
-  // declaration of ADIOSStream
-  OptionsADIOS() {}
-  OptionsADIOS(std::string filename,
-               bout::OptionsIO::FileMode mode = bout::OptionsIO::FileMode::replace,
-               bool singleWriteFile = false)
-      : OptionsIO(filename, mode, singleWriteFile) {}
-  OptionsADIOS(const OptionsADIOS&) = delete;
-  OptionsADIOS(OptionsADIOS&&) noexcept = default;
-  ~OptionsADIOS() = default;
-
-  OptionsADIOS& operator=(const OptionsADIOS&) = delete;
-  OptionsADIOS& operator=(OptionsADIOS&&) noexcept = default;
-
-  /// Read options from file
-  Options read() override;
-
-  /// Write options to file
-  void write(const Options& options) override { write(options, "t"); }
-  void write(const Options& options, const std::string& time_dim) override;
-
-  /// Check that all variables with the same time dimension have the
-  /// same size in that dimension. Throws BoutException if there are
-  /// any differences, otherwise is silent
-  void verifyTimesteps() const override;
-
-private:
-};
-
-} // namespace bout
-
-#endif // BOUT_HAS_ADIOS
-
-#endif //  __OPTIONS_ADIOS_H__
diff --git a/include/bout/options_io.hxx b/include/bout/options_io.hxx
index d8f26dc8ef..0139609417 100644
--- a/include/bout/options_io.hxx
+++ b/include/bout/options_io.hxx
@@ -6,40 +6,29 @@
 #define OPTIONS_IO_H
 
 #include "bout/build_config.hxx"
+#include "bout/generic_factory.hxx"
+#include "bout/options.hxx"
 
 #include <memory>
 #include <string>
 
-#include "bout/options.hxx"
-
 namespace bout {
 
 class OptionsIO {
 public:
-  enum class FileMode {
-    replace, ///< Overwrite file when writing
-    append   ///< Append to file when writing
-  };
-
-  enum class Library { ADIOS, NetCDF, Invalid };
-
-  static const Library defaultIOLibrary =
-#if BOUT_HAS_ADIOS
-      Library::NetCDF;
-#elif BOUT_HAS_NETCDF
-      Library::NetCDF;
-#else
-      Library::Invalid;
-#endif
+  /// No default constructor, as settings are required
+  OptionsIO() = delete;
+
+  /// Constructor specifies the kind of file, and options to control
+  /// the name of file, mode of operation etc.
+  OptionsIO(Options&) {}
+
+  virtual ~OptionsIO() = default;
 
-  OptionsIO();
-  OptionsIO(std::string filename, FileMode mode = FileMode::replace,
-            bool singleWriteFile = false);
-  virtual ~OptionsIO();
   OptionsIO(const OptionsIO&) = delete;
-  OptionsIO(OptionsIO&&) noexcept;
+  OptionsIO(OptionsIO&&) noexcept = default;
   OptionsIO& operator=(const OptionsIO&) = delete;
-  OptionsIO& operator=(OptionsIO&&) noexcept;
+  OptionsIO& operator=(OptionsIO&&) noexcept = default;
 
   /// Read options from file
   virtual Options read() = 0;
@@ -54,46 +43,72 @@ public:
   /// ADIOS: Indicate completion of an output step.
   virtual void verifyTimesteps() const = 0;
 
-  /// ADIOS: close file at the end of write(). NetCDF: no effect.
-  /// restart file must have this true if using ADIOS
-  //void setSingleWriteFile(const bool flag) { singleWriteFile = flag; };
+  static std::unique_ptr<OptionsIO> create(const std::string& file);
+};
+
+class OptionsIOFactory : public Factory<OptionsIO, OptionsIOFactory, Options&> {
+public:
+  static constexpr auto type_name = "OptionsIO";
+  static constexpr auto section_name = "io";
+  static constexpr auto option_name = "type";
+  static constexpr auto default_type =
+#if BOUT_HAS_NETCDF
+      "netcdf";
+#elif BOUT_HAS_ADIOS
+      "adios";
+#else
+      "invalid";
+#endif
 
-protected:
-  /// Name of the file on disk
-  std::string filename;
-  /// How to open the file for writing
-  FileMode file_mode{FileMode::replace};
-  bool singleWriteFile = false;
+  /// Create a restart file, configured with options (if given),
+  /// or root "restart_files" section.
+  ///
+  /// Options:
+  ///  - "type"    The type of file e.g "netcdf" or "adios"
+  ///  - "file"    Name of the file. Default is <path>/<prefix>.[type-dependent]
+  ///  - "path"    Path to restart files. Default is root "datadir" option,
+  ///              that defaults to "data"
+  ///  - "prefix"  Default is "BOUT.restart"
+  ReturnType createRestart(Options* optionsptr = nullptr) const;
+
+  /// Create an output file for writing time history.
+  /// Configure with options (if given), or root "output" section.
+  ///
+  /// Options:
+  ///  - "type"    The type of file e.g "netcdf" or "adios"
+  ///  - "file"    Name of the file. Default is <path>/<prefix>.[type]
+  ///  - "path"    Path to output files. Default is root "datadir" option,
+  ///              that defaults to "data"
+  ///  - "prefix"  Default is "BOUT.dmp"
+  ///  - "append"  Append to existing file? Default is root "append" option,
+  ///              that defaults to false.
+  ReturnType createOutput(Options* optionsptr = nullptr) const;
+
+  /// Create a single file (e.g. mesh file) of the default type
+  ReturnType createFile(const std::string& file) const;
 };
 
-std::shared_ptr<OptionsIO>
-OptionsIOFactory(std::string filename,
-                 OptionsIO::FileMode mode = OptionsIO::FileMode::replace,
-                 const OptionsIO::Library library = OptionsIO::defaultIOLibrary,
-                 const bool singleWriteFile = false);
-
-OptionsIO::Library getIOLibrary(Options& options);
-
-/// Name of the directory for restart files
-std::string getRestartDirectoryName(Options& options);
-/// Name of the restart file on this rank
-std::string getRestartFilename(Options& options, const OptionsIO::Library library);
-/// Name of the restart file on \p rank
-std::string getRestartFilename(Options& options, int rank,
-                               const OptionsIO::Library library);
-/// Name of the main output file on this rank
-std::string getOutputFilename(Options& options, const OptionsIO::Library library);
-/// Name of the main output file on \p rank
-std::string getOutputFilename(Options& options, int rank,
-                              const OptionsIO::Library library);
-/// Write `Options::root()` to the main output file, overwriting any
-/// existing files
-void writeDefaultOutputFile(
-    const OptionsIO::Library library = OptionsIO::defaultIOLibrary);
-/// Write \p options to the main output file, overwriting any existing
-/// files
-void writeDefaultOutputFile(
-    Options& options, const OptionsIO::Library library = OptionsIO::defaultIOLibrary);
+/// Simpler name for Factory registration helper class
+///
+/// Usage:
+///
+///     #include <bout/options_io.hxx>
+///     namespace {
+///     RegisterOptionsIO<MyOptionsIO> registeroptionsiomine("myoptionsio");
+///     }
+template <typename DerivedType>
+using RegisterOptionsIO = OptionsIOFactory::RegisterInFactory<DerivedType>;
+
+/// Simpler name for indicating that an OptionsIO implementation
+/// is unavailable.
+///
+/// Usage:
+///
+///     namespace {
+///     RegisterUnavailableOptionsIO
+///         unavailablemyoptionsio("myoptiosio", "BOUT++ was not configured with MyOptionsIO");
+///     }
+using RegisterUnavailableOptionsIO = OptionsIOFactory::RegisterUnavailableInFactory;
 
 } // namespace bout
 
diff --git a/include/bout/options_netcdf.hxx b/include/bout/options_netcdf.hxx
deleted file mode 100644
index 5cbbf7e5fc..0000000000
--- a/include/bout/options_netcdf.hxx
+++ /dev/null
@@ -1,91 +0,0 @@
-
-#pragma once
-
-#ifndef __OPTIONS_NETCDF_H__
-#define __OPTIONS_NETCDF_H__
-
-#include "bout/build_config.hxx"
-
-#include "bout/options.hxx"
-#include "bout/options_io.hxx"
-
-#if !BOUT_HAS_NETCDF || BOUT_HAS_LEGACY_NETCDF
-
-#include <string>
-
-#include "bout/boutexception.hxx"
-#include "bout/options.hxx"
-
-namespace bout {
-
-class OptionsNetCDF : public OptionsIO {
-public:
-  OptionsNetCDF(const std::string& filename,
-                bout::OptionsIO::FileMode mode = bout::OptionsIO::FileMode::replace,
-                bool singleWriteFile = false) {}
-  OptionsNetCDF(const OptionsNetCDF&) = default;
-  OptionsNetCDF(OptionsNetCDF&&) = default;
-  OptionsNetCDF& operator=(const OptionsNetCDF&) = default;
-  OptionsNetCDF& operator=(OptionsNetCDF&&) = default;
-
-  /// Read options from file
-  Options read() { throw BoutException("OptionsNetCDF not available\n"); }
-
-  /// Write options to file
-  void write(const Options& options, const std::string& time_dim) {
-    throw BoutException("OptionsNetCDF not available\n");
-  }
-
-  void verifyTimesteps() const { throw BoutException("OptionsADIOS not available\n"); }
-};
-
-} // namespace bout
-
-#else
-
-#include <memory>
-#include <string>
-
-/// Forward declare netCDF file type so we don't need to depend
-/// directly on netCDF
-namespace netCDF {
-class NcFile;
-}
-
-namespace bout {
-
-class OptionsNetCDF : public OptionsIO {
-public:
-  // Constructors need to be defined in implementation due to forward
-  // declaration of NcFile
-  OptionsNetCDF();
-  OptionsNetCDF(std::string filename, FileMode mode = FileMode::replace,
-                bool singleWriteFile = false);
-  ~OptionsNetCDF();
-  OptionsNetCDF(const OptionsNetCDF&) = delete;
-  OptionsNetCDF(OptionsNetCDF&&) noexcept;
-  OptionsNetCDF& operator=(const OptionsNetCDF&) = delete;
-  OptionsNetCDF& operator=(OptionsNetCDF&&) noexcept;
-
-  /// Read options from file
-  Options read();
-
-  /// Write options to file
-  void write(const Options& options) { write(options, "t"); }
-  void write(const Options& options, const std::string& time_dim);
-
-  /// Check that all variables with the same time dimension have the
-  /// same size in that dimension. Throws BoutException if there are
-  /// any differences, otherwise is silent
-  void verifyTimesteps() const;
-
-private:
-  /// Pointer to netCDF file so we don't introduce direct dependence
-  std::unique_ptr<netCDF::NcFile> data_file;
-};
-
-} // namespace bout
-
-#endif
-
-#endif //  __OPTIONS_NETCDF_H__
diff --git a/include/bout/physicsmodel.hxx b/include/bout/physicsmodel.hxx
index eb1bae8ae1..e0f046eb1f 100644
--- a/include/bout/physicsmodel.hxx
+++ b/include/bout/physicsmodel.hxx
@@ -88,9 +88,6 @@ public:
   void add(Vector2D* value, const std::string& name, bool save_repeat = false);
   void add(Vector3D* value, const std::string& name, bool save_repeat = false);
 
-  /// Write stored data to file immediately
-  bool write();
-
 private:
   /// Helper struct to save enough information so that we can save an
   /// object to file later
@@ -148,7 +145,7 @@ public:
   bout::DataFileFacade restart{};
 
   /*!
-   * Initialse the model, calling the init() and postInit() methods
+   * Initialise the model, calling the init() and postInit() methods
    *
    * Note: this is usually only called by the Solver
    */
@@ -383,13 +380,13 @@ private:
   /// State for outputs
   Options output_options;
   /// File to write the outputs to
-  std::shared_ptr<bout::OptionsIO> output_file;
+  std::unique_ptr<bout::OptionsIO> output_file;
   /// Should we write output files
   bool output_enabled{true};
   /// Stores the state for restarting
   Options restart_options;
   /// File to write the restart-state to
-  std::shared_ptr<bout::OptionsIO> restart_file;
+  std::unique_ptr<bout::OptionsIO> restart_file;
   /// Should we write restart files
   bool restart_enabled{true};
   /// Split operator model?
diff --git a/include/bout/solver.hxx b/include/bout/solver.hxx
index 8a3f07c27a..ef7cbe63eb 100644
--- a/include/bout/solver.hxx
+++ b/include/bout/solver.hxx
@@ -33,8 +33,8 @@
  *
  **************************************************************************/
 
-#ifndef __SOLVER_H__
-#define __SOLVER_H__
+#ifndef SOLVER_H
+#define SOLVER_H
 
 #include "bout/build_config.hxx"
 
@@ -597,4 +597,4 @@ private:
   BoutReal output_timestep;
 };
 
-#endif // __SOLVER_H__
+#endif // SOLVER_H
diff --git a/src/bout++.cxx b/src/bout++.cxx
index a42b0dcff8..1dc93dc76d 100644
--- a/src/bout++.cxx
+++ b/src/bout++.cxx
@@ -4,9 +4,9 @@
  * Adapted from the BOUT code by B.Dudson, University of York, Oct 2007
  *
  **************************************************************************
- * Copyright 2010 B.D.Dudson, S.Farley, M.V.Umansky, X.Q.Xu
+ * Copyright 2010-2023 BOUT++ contributors
  *
- * Contact Ben Dudson, bd512@york.ac.uk
+ * Contact Ben Dudson, dudson2@llnl.gov
  *
  * This file is part of BOUT++.
  *
diff --git a/src/mesh/data/gridfromfile.cxx b/src/mesh/data/gridfromfile.cxx
index 7e875bd109..aa66b145c7 100644
--- a/src/mesh/data/gridfromfile.cxx
+++ b/src/mesh/data/gridfromfile.cxx
@@ -6,7 +6,7 @@
 #include <bout/constants.hxx>
 #include <bout/fft.hxx>
 #include <bout/msg_stack.hxx>
-#include <bout/options_netcdf.hxx>
+#include <bout/options_io.hxx>
 #include <bout/output.hxx>
 #include <bout/sys/timer.hxx>
 #include <bout/unused.hxx>
@@ -14,7 +14,7 @@
 #include <utility>
 
 GridFile::GridFile(std::string gridfilename)
-    : GridDataSource(true), data(bout::OptionsNetCDF(gridfilename).read()),
+    : GridDataSource(true), data(bout::OptionsIO::create(gridfilename)->read()),
       filename(std::move(gridfilename)) {
   TRACE("GridFile constructor");
 
diff --git a/src/physics/physicsmodel.cxx b/src/physics/physicsmodel.cxx
index 538851f4cb..9f538895ed 100644
--- a/src/physics/physicsmodel.cxx
+++ b/src/physics/physicsmodel.cxx
@@ -58,18 +58,6 @@ void DataFileFacade::add(Vector3D* value, const std::string& name, bool save_rep
   add(value->y, name_prefix + "y"s, save_repeat);
   add(value->z, name_prefix + "z"s, save_repeat);
 }
-
-bool DataFileFacade::write() {
-  for (const auto& item : data) {
-    bout::utils::visit(bout::OptionsConversionVisitor{Options::root(), item.name},
-                       item.value);
-    if (item.repeat) {
-      Options::root()[item.name].attributes["time_dimension"] = "t";
-    }
-  }
-  writeDefaultOutputFile();
-  return true;
-}
 } // namespace bout
 
 PhysicsModel::PhysicsModel()
@@ -81,21 +69,12 @@ PhysicsModel::PhysicsModel()
                           .withDefault(true))
 
 {
-  bout::OptionsIO::Library iolibrary = bout::getIOLibrary(Options::root());
   if (output_enabled) {
-    std::string outputFileName = bout::getOutputFilename(Options::root(), iolibrary);
-    auto mode = Options::root()["append"]
-                        .doc("Add output data to existing (dump) files?")
-                        .withDefault(false)
-                    ? bout::OptionsIO::FileMode::append
-                    : bout::OptionsIO::FileMode::replace;
-    output_file = bout::OptionsIOFactory(outputFileName, mode, iolibrary);
+    output_file = bout::OptionsIOFactory::getInstance().createOutput();
   }
 
   if (restart_enabled) {
-    std::string restartFileName = bout::getRestartFilename(Options::root(), iolibrary);
-    restart_file = bout::OptionsIOFactory(
-        restartFileName, bout::OptionsIO::FileMode::replace, iolibrary, true);
+    restart_file = bout::OptionsIOFactory::getInstance().createRestart();
   }
 }
 
diff --git a/src/sys/options/options_adios.cxx b/src/sys/options/options_adios.cxx
index a032fd1629..fd8e978091 100644
--- a/src/sys/options/options_adios.cxx
+++ b/src/sys/options/options_adios.cxx
@@ -2,8 +2,8 @@
 
 #if BOUT_HAS_ADIOS
 
+#include "options_adios.hxx"
 #include "bout/adios_object.hxx"
-#include "bout/options_adios.hxx"
 
 #include "bout/bout.hxx"
 #include "bout/globals.hxx"
@@ -19,6 +19,22 @@ namespace bout {
 /// Name of the attribute used to track individual variable's time indices
 constexpr auto current_time_index_name = "current_time_index";
 
+OptionsADIOS::OptionsADIOS(Options& options) {
+  if (options["file"].doc("File name. Defaults to <path>/<prefix>.pb").isSet()) {
+    filename = options["file"].as<std::string>();
+  } else {
+    // Both path and prefix must be set
+    filename = fmt::format("{}/{}.bp", options["path"].as<std::string>(),
+                           options["prefix"].as<std::string>());
+  }
+
+  file_mode = (options["append"].doc("Append to existing file?").withDefault<bool>(false))
+                  ? FileMode::append
+                  : FileMode::replace;
+
+  singleWriteFile = options["singleWriteFile"].withDefault<bool>(false);
+}
+
 template <class T>
 bool readVariable(adios2::Engine& reader, adios2::IO& io, const std::string& name,
                   const std::string& type, Options& result) {
diff --git a/src/sys/options/options_adios.hxx b/src/sys/options/options_adios.hxx
new file mode 100644
index 0000000000..2460dfd10c
--- /dev/null
+++ b/src/sys/options/options_adios.hxx
@@ -0,0 +1,84 @@
+
+#pragma once
+
+#ifndef OPTIONS_ADIOS_H
+#define OPTIONS_ADIOS_H
+
+#include "bout/build_config.hxx"
+#include "bout/options.hxx"
+#include "bout/options_io.hxx"
+
+#if !BOUT_HAS_ADIOS
+
+namespace {
+bout::RegisterUnavailableOptionsIO
+    registerunavailableoptionsadios("adios", "BOUT++ was not configured with ADIOS2");
+}
+
+#else
+
+#include <memory>
+#include <string>
+
+namespace bout {
+
+/// Forward declare ADIOS file type so we don't need to depend
+/// directly on ADIOS
+struct ADIOSStream;
+
+class OptionsADIOS : public OptionsIO {
+public:
+  // Constructors need to be defined in implementation due to forward
+  // declaration of ADIOSStream
+  OptionsADIOS() = delete;
+
+  /// Create an OptionsADIOS
+  ///
+  /// Options:
+  ///  - "file"   The name of the file
+  ///    If not set then "path" and "prefix" must be set,
+  ///    and file is set to {path}/{prefix}.bp
+  ///  - "append"
+  ///  - "singleWriteFile"
+  OptionsADIOS(Options& options);
+
+  OptionsADIOS(const OptionsADIOS&) = delete;
+  OptionsADIOS(OptionsADIOS&&) noexcept = default;
+  ~OptionsADIOS() = default;
+
+  OptionsADIOS& operator=(const OptionsADIOS&) = delete;
+  OptionsADIOS& operator=(OptionsADIOS&&) noexcept = default;
+
+  /// Read options from file
+  Options read() override;
+
+  /// Write options to file
+  void write(const Options& options) override { write(options, "t"); }
+  void write(const Options& options, const std::string& time_dim) override;
+
+  /// Check that all variables with the same time dimension have the
+  /// same size in that dimension. Throws BoutException if there are
+  /// any differences, otherwise is silent
+  void verifyTimesteps() const override;
+
+private:
+  enum class FileMode {
+    replace, ///< Overwrite file when writing
+    append   ///< Append to file when writing
+  };
+
+  /// Name of the file on disk
+  std::string filename;
+  /// How to open the file for writing
+  FileMode file_mode{FileMode::replace};
+  bool singleWriteFile = false;
+};
+
+namespace {
+RegisterOptionsIO<OptionsADIOS> registeroptionsadios("adios");
+}
+
+} // namespace bout
+
+#endif // BOUT_HAS_ADIOS
+#endif // OPTIONS_ADIOS_H
diff --git a/src/sys/options/options_io.cxx b/src/sys/options/options_io.cxx
index 514307ec59..0d25591db7 100644
--- a/src/sys/options/options_io.cxx
+++ b/src/sys/options/options_io.cxx
@@ -1,118 +1,41 @@
-#include "bout/build_config.hxx"
-
 #include "bout/options_io.hxx"
 
-#include "bout/bout.hxx"
-#include "bout/globals.hxx"
-#include "bout/mesh.hxx"
-#include "bout/sys/timer.hxx"
-
-#include <exception>
-#include <iostream>
-#include <vector>
-
-#include "bout/options_adios.hxx"
-#include "bout/options_netcdf.hxx"
+#include "options_adios.hxx"
+#include "options_netcdf.hxx"
 
 namespace bout {
-
-OptionsIO::OptionsIO() {}
-
-OptionsIO::OptionsIO(std::string filename, FileMode mode, bool singleWriteFile)
-    : filename(std::move(filename)), file_mode(mode), singleWriteFile(singleWriteFile) {}
-
-OptionsIO::~OptionsIO() = default;
-OptionsIO::OptionsIO(OptionsIO&&) noexcept = default;
-OptionsIO& OptionsIO::operator=(OptionsIO&&) noexcept = default;
-
-OptionsIO::Library getIOLibrary(Options& options) {
-  if (options["iolibrary"].isSet()) {
-    // Solver-specific IO library
-    std::string iolib = options["iolibrary"];
-    std::transform(iolib.begin(), iolib.end(), iolib.begin(), ::tolower);
-    if (iolib == "adios")
-      return OptionsIO::Library::ADIOS;
-    else if (iolib == "netcdf")
-      return OptionsIO::Library::NetCDF;
-    else
-      return OptionsIO::Library::Invalid;
-  } else {
-    return OptionsIO::defaultIOLibrary;
-  }
+std::unique_ptr<OptionsIO> OptionsIO::create(const std::string& file) {
+  return OptionsIOFactory::getInstance().createFile(file);
 }
 
-std::shared_ptr<OptionsIO> OptionsIOFactory(std::string filename,
-                                            OptionsIO::FileMode mode,
-                                            const OptionsIO::Library library,
-                                            const bool singleWriteFile) {
-  if (library == OptionsIO::Library::ADIOS) {
-    return std::make_shared<OptionsADIOS>(OptionsADIOS(filename, mode, singleWriteFile));
-  } else if (library == OptionsIO::Library::NetCDF) {
-    return std::make_shared<OptionsNetCDF>(
-        OptionsNetCDF(filename, mode, singleWriteFile));
-  } else {
-    return nullptr;
-  }
-}
+OptionsIOFactory::ReturnType OptionsIOFactory::createRestart(Options* optionsptr) const {
+  Options& options = optionsptr ? *optionsptr : Options::root()["restart_files"];
 
-std::string getRestartDirectoryName(Options& options) {
-  if (options["restartdir"].isSet()) {
-    // Solver-specific restart directory
-    return options["restartdir"].withDefault<std::string>("data");
-  }
-  // Use the root data directory
-  return options["datadir"].withDefault<std::string>("data");
+  // Set defaults
+  options["path"].overrideDefault(
+      Options::root()["datadir"].withDefault<std::string>("data"));
+  options["prefix"].overrideDefault("BOUT.restart");
+  options["append"].overrideDefault(false);
+  options["singleWriteFile"].overrideDefault(true);
+  return create(getType(&options), options);
 }
 
-std::string getRestartFilename(Options& options, const OptionsIO::Library library) {
-  return getRestartFilename(options, BoutComm::rank(), library);
-}
-
-std::string getRestartFilename(Options& options, int rank,
-                               const OptionsIO::Library library) {
-  if (library == OptionsIO::Library::ADIOS)
-    return fmt::format("{}/BOUT.restart.bp", bout::getRestartDirectoryName(options));
-  else if (library == OptionsIO::Library::NetCDF)
-    return fmt::format("{}/BOUT.restart.{}.nc", bout::getRestartDirectoryName(options),
-                       rank);
-  else
-    return fmt::format("{}/BOUT.restart.{}.data", bout::getRestartDirectoryName(options),
-                       rank);
-}
-
-std::string getOutputFilename(Options& options, const OptionsIO::Library library) {
-  return getOutputFilename(options, BoutComm::rank(), library);
-}
-
-std::string getOutputFilename(Options& options, int rank,
-                              const OptionsIO::Library library) {
-  if (library == OptionsIO::Library::ADIOS)
-    return fmt::format("{}/BOUT.dmp.bp",
-                       options["datadir"].withDefault<std::string>("data"));
-  else if (library == OptionsIO::Library::NetCDF)
-    return fmt::format("{}/BOUT.dmp.{}.nc",
-                       options["datadir"].withDefault<std::string>("data"), rank);
-  else
-    return fmt::format("{}/BOUT.dmp.{}.data",
-                       options["datadir"].withDefault<std::string>("data"), rank);
-}
+OptionsIOFactory::ReturnType OptionsIOFactory::createOutput(Options* optionsptr) const {
+  Options& options = optionsptr ? *optionsptr : Options::root()["output"];
 
-void writeDefaultOutputFile(const OptionsIO::Library library) {
-  writeDefaultOutputFile(Options::root(), library);
+  // Set defaults
+  options["path"].overrideDefault(
+      Options::root()["datadir"].withDefault<std::string>("data"));
+  options["prefix"].overrideDefault("BOUT.dmp");
+  options["append"].overrideDefault(Options::root()["append"]
+                                        .doc("Add output data to existing (dump) files?")
+                                        .withDefault<bool>(false));
+  return create(getType(&options), options);
 }
 
-void writeDefaultOutputFile(Options& options, const OptionsIO::Library library) {
-  bout::experimental::addBuildFlagsToOptions(options);
-  bout::globals::mesh->outputVars(options);
-  auto mode = options["append"]
-                      .doc("Add output data to existing (dump) files?")
-                      .withDefault(false)
-                  ? bout::OptionsIO::FileMode::append
-                  : bout::OptionsIO::FileMode::replace;
-  // Note: `options` contains the data to write.
-  //       Get the output file from the `Options::root()` input settings.
-  auto io = OptionsIOFactory(getOutputFilename(Options::root(), library), mode, library);
-  io->write(options);
+OptionsIOFactory::ReturnType OptionsIOFactory::createFile(const std::string& file) const {
+  Options options{{"file", file}};
+  return create(getDefaultType(), options);
 }
 
 } // namespace bout
diff --git a/src/sys/options/options_netcdf.cxx b/src/sys/options/options_netcdf.cxx
index 0262e0cbbd..eda2b0bfbd 100644
--- a/src/sys/options/options_netcdf.cxx
+++ b/src/sys/options/options_netcdf.cxx
@@ -2,7 +2,7 @@
 
 #if BOUT_HAS_NETCDF && !BOUT_HAS_LEGACY_NETCDF
 
-#include "bout/options_netcdf.hxx"
+#include "options_netcdf.hxx"
 
 #include "bout/bout.hxx"
 #include "bout/globals.hxx"
@@ -643,14 +643,19 @@ std::vector<TimeDimensionError> verifyTimesteps(const NcGroup& group) {
 
 namespace bout {
 
-OptionsNetCDF::OptionsNetCDF() : data_file(nullptr) {}
-
-OptionsNetCDF::OptionsNetCDF(std::string filename, FileMode mode, bool singleWriteFile)
-    : OptionsIO(filename, mode, singleWriteFile), data_file(nullptr) {}
+OptionsNetCDF::OptionsNetCDF(Options& options) : OptionsIO(options) {
+  if (options["file"].doc("File name. Defaults to <path>/<prefix>.<rank>.nc").isSet()) {
+    filename = options["file"].as<std::string>();
+  } else {
+    // Both path and prefix must be set
+    filename = fmt::format("{}/{}.{}.nc", options["path"].as<std::string>(),
+                           options["prefix"].as<std::string>(), BoutComm::rank());
+  }
 
-OptionsNetCDF::~OptionsNetCDF() = default;
-OptionsNetCDF::OptionsNetCDF(OptionsNetCDF&&) noexcept = default;
-OptionsNetCDF& OptionsNetCDF::operator=(OptionsNetCDF&&) noexcept = default;
+  file_mode = (options["append"].doc("Append to existing file?").withDefault<bool>(false))
+                  ? FileMode::append
+                  : FileMode::replace;
+}
 
 void OptionsNetCDF::verifyTimesteps() const {
   NcFile dataFile(filename, NcFile::read);
diff --git a/src/sys/options/options_netcdf.hxx b/src/sys/options/options_netcdf.hxx
new file mode 100644
index 0000000000..8f195c9d92
--- /dev/null
+++ b/src/sys/options/options_netcdf.hxx
@@ -0,0 +1,84 @@
+
+#pragma once
+
+#ifndef OPTIONS_NETCDF_H
+#define OPTIONS_NETCDF_H
+
+#include "bout/build_config.hxx"
+
+#include "bout/options.hxx"
+#include "bout/options_io.hxx"
+
+#if !BOUT_HAS_NETCDF || BOUT_HAS_LEGACY_NETCDF
+
+namespace {
+RegisterUnavailableOptionsIO
+    registerunavailableoptionsnetcdf("netcdf", "BOUT++ was not configured with NetCDF");
+}
+
+#else
+
+#include <memory>
+#include <netcdf>
+#include <string>
+
+namespace bout {
+
+class OptionsNetCDF : public OptionsIO {
+public:
+  // Constructors need to be defined in implementation due to forward
+  // declaration of NcFile
+  OptionsNetCDF() = delete;
+
+  /// Create an OptionsNetCDF
+  ///
+  /// Options:
+  ///  - "file"   The name of the file
+  ///    If not set then "path" and "prefix" options must be set,
+  ///    and file is set to {path}/{prefix}.{rank}.nc
+  ///  - "append"  File mode, default is false
+  OptionsNetCDF(Options& options);
+
+  ~OptionsNetCDF() {}
+
+  OptionsNetCDF(const OptionsNetCDF&) = delete;
+  OptionsNetCDF(OptionsNetCDF&&) noexcept = default;
+  OptionsNetCDF& operator=(const OptionsNetCDF&) = delete;
+  OptionsNetCDF& operator=(OptionsNetCDF&&) noexcept = default;
+
+  /// Read options from file
+  Options read();
+
+  /// Write options to file
+  void write(const Options& options) { write(options, "t"); }
+  void write(const Options& options, const std::string& time_dim);
+
+  /// Check that all variables with the same time dimension have the
+  /// same size in that dimension. Throws BoutException if there are
+  /// any differences, otherwise is silent
+  void verifyTimesteps() const;
+
+private:
+  enum class FileMode {
+    replace, ///< Overwrite file when writing
+    append   ///< Append to file when writing
+  };
+
+  /// Pointer to netCDF file so we don't introduce direct dependence
+  std::unique_ptr<netCDF::NcFile> data_file = nullptr;
+
+  /// Name of the file on disk
+  std::string filename;
+  /// How to open the file for writing
+  FileMode file_mode{FileMode::replace};
+};
+
+namespace {
+RegisterOptionsIO<OptionsNetCDF> registeroptionsnetcdf("netcdf");
+}
+
+} // namespace bout
+
+#endif
+
+#endif //  OPTIONS_NETCDF_H
diff --git a/tools/pylib/_boutpp_build/bout_options.pxd b/tools/pylib/_boutpp_build/bout_options.pxd
index ba5e64c8e3..550bfc01e1 100644
--- a/tools/pylib/_boutpp_build/bout_options.pxd
+++ b/tools/pylib/_boutpp_build/bout_options.pxd
@@ -8,20 +8,10 @@ cdef extern from "boutexception_helper.hxx":
      cdef void raise_bout_py_error()
 
 
-cdef extern from "bout/options_netcdf.hxx" namespace "bout":
-    cdef void writeDefaultOutputFile();
-    cdef void writeDefaultOutputFile(Options& options);
-    cppclass OptionsNetCDF:
-        enum FileMode:
-             replace
-             append
-        OptionsNetCDF() except +raise_bout_py_error
-        OptionsNetCDF(string filename) except +raise_bout_py_error
-        OptionsNetCDF(string filename, FileMode mode) except +raise_bout_py_error
-        OptionsNetCDF(const OptionsNetCDF&);
-        OptionsNetCDF(OptionsNetCDF&&);
-        OptionsNetCDF& operator=(const OptionsNetCDF&);
-        OptionsNetCDF& operator=(OptionsNetCDF&&);
+cdef extern from "bout/options_io.hxx" namespace "bout":
+    cppclass OptionsIO:
+        @staticmethod
+        OptionsIO * create(string filename)
         Options read();
         void write(const Options& options);
         void write(const Options& options, string time_dim);
diff --git a/tools/pylib/_boutpp_build/boutcpp.pxd.jinja b/tools/pylib/_boutpp_build/boutcpp.pxd.jinja
index c94fd14a17..28633cad95 100644
--- a/tools/pylib/_boutpp_build/boutcpp.pxd.jinja
+++ b/tools/pylib/_boutpp_build/boutcpp.pxd.jinja
@@ -5,7 +5,7 @@ from libcpp.memory cimport unique_ptr
 from libcpp.string cimport string
 
 cimport resolve_enum as benum
-from bout_options cimport Options, OptionsReader, OptionsNetCDF, writeDefaultOutputFile
+from bout_options cimport Options, OptionsReader, OptionsIO
 
 cdef extern from "boutexception_helper.hxx":
      cdef void raise_bout_py_error()
diff --git a/tools/pylib/_boutpp_build/boutpp.pyx.jinja b/tools/pylib/_boutpp_build/boutpp.pyx.jinja
index 657e2f28c1..a8c027475a 100644
--- a/tools/pylib/_boutpp_build/boutpp.pyx.jinja
+++ b/tools/pylib/_boutpp_build/boutpp.pyx.jinja
@@ -1723,10 +1723,6 @@ cdef class Options:
             del self.cobj
             self.cobj = NULL
 
-
-def writeDefaultOutputFile(options: Options):
-    c.writeDefaultOutputFile(deref(options.cobj))
-
 def print(*args, sep=" ", end="\n"):
     _print(sep.join([str(a) for a in args]) + end)