diff --git a/core/coresignal.h b/core/coresignal.h
index 198180f..78a1b3d 100644
--- a/core/coresignal.h
+++ b/core/coresignal.h
@@ -53,6 +53,9 @@ public:
 
     // Calls all connected slots.
     void emit(Args... args) {
+        if (!_is_enabled) {
+            return;
+        }
         for (auto const& it : _slots) {
             it.second(args...);
         }
@@ -66,9 +69,22 @@ public:
         _slots.clear();
     }
 
+    void disable() {
+        _is_enabled = false;
+    }
+
+    void enable() {
+        _is_enabled = true;
+    }
+
+    bool is_enabled() {
+        return _is_enabled;
+    }
+
 private:
     mutable std::map<int, std::function<void(Args...)>> _slots;
     mutable unsigned int _current_id { 0 };
+    mutable bool _is_enabled { true };
 };
 
 #endif // CORE_SIGNAL_H
diff --git a/core/hostevents.h b/core/hostevents.h
index 03e6134..cd149d5 100644
--- a/core/hostevents.h
+++ b/core/hostevents.h
@@ -146,6 +146,11 @@ public:
         _post_signal.disconnect_all();
     }
 
+    void disable_input_handlers() {
+        _mouse_signal.disable();
+        _keyboard_signal.disable();
+    }
+
 private:
     static EventManager* event_manager;
     EventManager() {}; // private constructor to implement a singleton
diff --git a/core/timermanager.h b/core/timermanager.h
index 465742e..51a37c3 100644
--- a/core/timermanager.h
+++ b/core/timermanager.h
@@ -31,8 +31,6 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <vector>
 #include <mutex>
 
-using namespace std;
-
 #define NS_PER_SEC      1000000000
 #define USEC_PER_SEC    1000000
 #define NS_PER_USEC     1000
@@ -42,7 +40,7 @@ using namespace std;
 #define USECS_TO_NSECS(us) (us) * NS_PER_USEC
 #define MSECS_TO_NSECS(ms) (ms) * NS_PER_MSEC
 
-typedef function<void()> timer_cb;
+typedef std::function<void()> timer_cb;
 
 /** Extend std::priority_queue as suggested here:
     https://stackoverflow.com/a/36711682
@@ -101,7 +99,7 @@ typedef struct TimerInfo {
 // Custom comparator for sorting our timer queue in ascending order
 class MyGtComparator {
 public:
-    bool operator()(const shared_ptr<TimerInfo>& l, const shared_ptr<TimerInfo>& r) {
+    bool operator()(const std::shared_ptr<TimerInfo>& l, const std::shared_ptr<TimerInfo>& r) {
         return l.get()->timeout_ns > r.get()->timeout_ns;
     }
 };
@@ -116,7 +114,7 @@ public:
     };
 
     // callback for retrieving current time
-    void set_time_now_cb(const function<uint64_t()> &cb) {
+    void set_time_now_cb(const std::function<uint64_t()> &cb) {
         this->get_time_now = cb;
     };
 
@@ -142,10 +140,10 @@ private:
     TimerManager(){}; // private constructor to implement a singleton
 
     // timer queue
-    my_priority_queue<shared_ptr<TimerInfo>, vector<shared_ptr<TimerInfo>>, MyGtComparator> timer_queue;
+    my_priority_queue<std::shared_ptr<TimerInfo>, std::vector<std::shared_ptr<TimerInfo>>, MyGtComparator> timer_queue;
 
-    function<uint64_t()>   get_time_now;
-    function<void()>       notify_timer_changes;
+    std::function<uint64_t()>   get_time_now;
+    std::function<void()>       notify_timer_changes;
 
     std::atomic<uint32_t> id{0};
     bool        cb_active = false; // true if a timer callback is executing // FIXME: Do we need this? It gets written in main thread and read in audio thread.
diff --git a/cpu/ppc/ppcemu.h b/cpu/ppc/ppcemu.h
index 70d3f93..250913d 100644
--- a/cpu/ppc/ppcemu.h
+++ b/cpu/ppc/ppcemu.h
@@ -328,6 +328,9 @@ extern bool is_601;        // For PowerPC 601 Emulation
 extern bool is_altivec;    // For Altivec Emulation
 extern bool is_64bit;      // For PowerPC G5 Emulation
 
+// Make execution deterministic (ignore external input, used a fixed date, etc.)
+extern bool is_deterministic;
+
 // Important Addressing Integers
 extern uint32_t ppc_cur_instruction;
 extern uint32_t ppc_next_instruction_address;
diff --git a/cpu/ppc/ppcexec.cpp b/cpu/ppc/ppcexec.cpp
index e0fb6b2..8d8a3c8 100644
--- a/cpu/ppc/ppcexec.cpp
+++ b/cpu/ppc/ppcexec.cpp
@@ -57,6 +57,8 @@ MemCtrlBase* mem_ctrl_instance = 0;
 
 bool is_601 = false;
 
+bool is_deterministic = false;
+
 bool power_on = false;
 Po_Cause power_off_reason = po_enter_debugger;
 
diff --git a/devices/common/nvram.cpp b/devices/common/nvram.cpp
index 455ef0c..db21763 100644
--- a/devices/common/nvram.cpp
+++ b/devices/common/nvram.cpp
@@ -19,6 +19,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
+#include <cpu/ppc/ppcemu.h>
 #include <devices/common/hwcomponent.h>
 #include <devices/common/nvram.h>
 #include <devices/deviceregistry.h>
@@ -81,6 +82,10 @@ void NVram::init() {
 }
 
 void NVram::save() {
+    if (is_deterministic) {
+        LOG_F(INFO, "Skipping NVRAM write to \"%s\" in deterministic mode", this->file_name.c_str());
+        return;
+    }
     ofstream f(this->file_name, ios::out | ios::binary);
 
     /* write file identification */
diff --git a/devices/common/viacuda.cpp b/devices/common/viacuda.cpp
index 807b3c3..33467ee 100644
--- a/devices/common/viacuda.cpp
+++ b/devices/common/viacuda.cpp
@@ -751,7 +751,22 @@ void ViaCuda::pseudo_command() {
 }
 
 uint32_t ViaCuda::calc_real_time() {
-    auto end = std::chrono::system_clock::now();
+    std::chrono::time_point<std::chrono::system_clock> end;
+    if (is_deterministic) {
+        // March 24, 2001 was the public release date of Mac OS X.
+        std::tm tm = {
+            .tm_sec  = 0,
+            .tm_min  = 0,
+            .tm_hour = 12,
+            .tm_mday = 24,
+            .tm_mon  = 3 - 1,
+            .tm_year = 2001 - 1900,
+            .tm_isdst = 0
+        };
+        end = std::chrono::system_clock::from_time_t(std::mktime(&tm));
+    } else {
+        end = std::chrono::system_clock::now();
+    }
     auto elapsed_systemclock = end - this->mac_epoch;
     auto elapsed_seconds = std::chrono::duration_cast<std::chrono::seconds>(elapsed_systemclock);
     return uint32_t(elapsed_seconds.count());
diff --git a/devices/sound/awacs.cpp b/devices/sound/awacs.cpp
index 863f10c..2f8449c 100644
--- a/devices/sound/awacs.cpp
+++ b/devices/sound/awacs.cpp
@@ -69,8 +69,7 @@ void AwacsBase::dma_out_start() {
     }
 
     if (!this->out_stream_ready) {
-        if ((err = this->snd_server->open_out_stream(this->cur_sample_rate,
-            (void *)this->dma_out_ch))) {
+        if ((err = this->snd_server->open_out_stream(this->cur_sample_rate, this->dma_out_ch))) {
             LOG_F(ERROR, "%s: unable to open sound output stream: %d",
                   this->name.c_str(), err);
             return;
diff --git a/devices/sound/soundserver.h b/devices/sound/soundserver.h
index cd74e99..8950f26 100644
--- a/devices/sound/soundserver.h
+++ b/devices/sound/soundserver.h
@@ -38,6 +38,8 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 #include <memory>
 
+class DmaOutChannel;
+
 class SoundServer : public HWComponent {
 public:
     SoundServer();
@@ -45,7 +47,7 @@ public:
 
     int start();
     void shutdown();
-    int open_out_stream(uint32_t sample_rate, void *user_data);
+    int open_out_stream(uint32_t sample_rate, DmaOutChannel *dma_ch);
     int start_out_stream();
     void close_out_stream();
 
diff --git a/devices/sound/soundserver_cubeb.cpp b/devices/sound/soundserver_cubeb.cpp
index 9831e68..f70bf0e 100644
--- a/devices/sound/soundserver_cubeb.cpp
+++ b/devices/sound/soundserver_cubeb.cpp
@@ -19,30 +19,40 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
+#ifndef NOMINMAX
+#define NOMINMAX
+#endif // NOMINMAX
+
+#include <core/timermanager.h>
+#include <cpu/ppc/ppcemu.h>
 #include <devices/common/dmacore.h>
 #include <devices/sound/soundserver.h>
 #include <endianswap.h>
 
+#include <algorithm>
+#include <functional>
 #include <loguru.hpp>
 #include <cubeb/cubeb.h>
 #ifdef _WIN32
 #include <objbase.h>
 #endif
 
-enum {
+typedef enum {
     SND_SERVER_DOWN = 0,
     SND_API_READY,
     SND_SERVER_UP,
     SND_STREAM_OPENED,
     SND_STREAM_CLOSED
-};
+} Status;
 
 class SoundServer::Impl {
 public:
-    int status;                     /* server status */
+    Status status = SND_SERVER_DOWN;
     cubeb *cubeb_ctx;
-
     cubeb_stream *out_stream;
+
+    uint32_t deterministic_poll_timer = 0;
+    std::function<void()> deterministic_poll_cb;
 };
 
 SoundServer::SoundServer(): impl(std::make_unique<Impl>())
@@ -91,6 +101,10 @@ void SoundServer::shutdown()
         /* fall through */
     case SND_API_READY:
         cubeb_destroy(impl->cubeb_ctx);
+        break;
+    case SND_SERVER_DOWN:
+        // Nothing to do.
+        break;
     }
 
     impl->status = SND_SERVER_DOWN;
@@ -148,8 +162,30 @@ static void status_callback(cubeb_stream *stream, void *user_data, cubeb_state s
     LOG_F(9, "Cubeb status callback fired, status = %d", state);
 }
 
-int SoundServer::open_out_stream(uint32_t sample_rate, void *user_data)
+int SoundServer::open_out_stream(uint32_t sample_rate, DmaOutChannel *dma_ch)
 {
+    if (is_deterministic) {
+        impl->deterministic_poll_cb = [dma_ch] {
+            if (!dma_ch->is_out_active()) {
+               return;
+            }
+            // Drain the DMA buffer, but don't do anything else.
+            int req_size = std::max(dma_ch->get_pull_data_remaining(), 1024);
+            int out_size = 0;
+            while (req_size > 0) {
+                uint8_t *chunk;
+                uint32_t chunk_size;
+                if (!dma_ch->pull_data(req_size, &chunk_size, &chunk)) {
+                    req_size -= chunk_size;
+                } else {
+                    break;
+                }
+            }
+        };
+        impl->status = SND_STREAM_OPENED;
+        LOG_F(9, "Deterministic sound output callback set up.");
+        return 0;
+    }
     int res;
     uint32_t latency_frames;
     cubeb_stream_params params;
@@ -170,7 +206,7 @@ int SoundServer::open_out_stream(uint32_t sample_rate, void *user_data)
 
     res = cubeb_stream_init(impl->cubeb_ctx, &impl->out_stream, "SndOut stream",
                             NULL, NULL, NULL, &params, latency_frames,
-                            sound_out_callback, status_callback, user_data);
+                            sound_out_callback, status_callback, dma_ch);
     if (res != CUBEB_OK) {
         LOG_F(ERROR, "Could not open sound output stream, error: %d", res);
         return -1;
@@ -185,11 +221,22 @@ int SoundServer::open_out_stream(uint32_t sample_rate, void *user_data)
 
 int SoundServer::start_out_stream()
 {
+    if (is_deterministic) {
+        LOG_F(9, "Starting sound output deterministic polling.");
+        impl->deterministic_poll_timer = TimerManager::get_instance()->add_cyclic_timer(MSECS_TO_NSECS(10), impl->deterministic_poll_cb);
+        return 0;
+    }
     return cubeb_stream_start(impl->out_stream);
 }
 
 void SoundServer::close_out_stream()
 {
+    if (is_deterministic) {
+        LOG_F(9, "Stopping sound output deterministic polling.");
+        TimerManager::get_instance()->cancel_timer(impl->deterministic_poll_timer);
+        impl->status = SND_STREAM_CLOSED;
+        return;
+    }
     cubeb_stream_stop(impl->out_stream);
     cubeb_stream_destroy(impl->out_stream);
     impl->status = SND_STREAM_CLOSED;
diff --git a/main.cpp b/main.cpp
index 4e67e49..382d75c 100644
--- a/main.cpp
+++ b/main.cpp
@@ -25,6 +25,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <core/hostevents.h>
 #include <core/timermanager.h>
 #include <cpu/ppc/ppcemu.h>
+#include <cpu/ppc/ppcdisasm.h>
 #include <debugger/debugger.h>
 #include <machines/machinebase.h>
 #include <machines/machinefactory.h>
@@ -82,6 +83,8 @@ int main(int argc, char** argv) {
         "Enter the built-in debugger");
     app.add_option("-b,--bootrom", bootrom_path, "Specifies BootROM path")
         ->check(CLI::ExistingFile);
+    app.add_flag("--deterministic", is_deterministic,
+        "Make execution deterministic");
 
     bool              log_to_stderr = false;
     loguru::Verbosity log_verbosity = loguru::Verbosity_INFO;
@@ -177,6 +180,9 @@ int main(int argc, char** argv) {
 
     cout << "BootROM path: " << bootrom_path << endl;
     cout << "Execution mode: " << execution_mode << endl;
+    if (is_deterministic) {
+        cout << "Using deterministic execution mode, input will be ignored." << endl;
+    }
 
     if (!init()) {
         LOG_F(ERROR, "Cannot initialize");
@@ -233,6 +239,21 @@ void run_machine(std::string machine_str, std::string bootrom_path, uint32_t exe
         return;
     }
 
+    uint32_t deterministic_timer;
+    if (is_deterministic) {
+        EventManager::get_instance()->disable_input_handlers();
+        // Log the PC and instruction every second to make it easier to validate
+        // that execution is the same every time.
+        deterministic_timer = TimerManager::get_instance()->add_cyclic_timer(MSECS_TO_NSECS(100), [] {
+            PPCDisasmContext ctx;
+            ctx.instr_code = ppc_cur_instruction;
+            ctx.instr_addr = 0;
+            ctx.simplified = false;
+            auto op_name = disassemble_single(&ctx);
+            LOG_F(INFO, "TS=%016llu PC=0x%08x executing %s", get_virt_time_ns(), ppc_state.pc, op_name.c_str());
+        });
+    }
+
     // set up system wide event polling using
     // default Macintosh polling rate of 11 ms
     uint32_t event_timer = TimerManager::get_instance()->add_cyclic_timer(MSECS_TO_NSECS(11), [] {
@@ -273,6 +294,9 @@ void run_machine(std::string machine_str, std::string bootrom_path, uint32_t exe
         TimerManager::get_instance()->cancel_timer(profiling_timer);
     }
 #endif
+    if (is_deterministic) {
+        TimerManager::get_instance()->cancel_timer(deterministic_timer);
+    }
     EventManager::get_instance()->disconnect_handlers();
     delete gMachineObj.release();
 }
diff --git a/utils/imgfile_sdl.cpp b/utils/imgfile_sdl.cpp
index 30d6b5f..a5d80c8 100644
--- a/utils/imgfile_sdl.cpp
+++ b/utils/imgfile_sdl.cpp
@@ -22,10 +22,14 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <utils/imgfile.h>
 
 #include <fstream>
+#include <sstream>
+#include <memory>
+
+extern bool is_deterministic;
 
 class ImgFile::Impl {
 public:
-    std::fstream stream;
+    std::unique_ptr<std::iostream> stream;
 };
 
 ImgFile::ImgFile(): impl(std::make_unique<Impl>())
@@ -37,31 +41,43 @@ ImgFile::~ImgFile() = default;
 
 bool ImgFile::open(const std::string &img_path)
 {
-    impl->stream.open(img_path, std::ios::in | std::ios::out | std::ios::binary);
-    return !impl->stream.fail();
+    if (is_deterministic) {
+        // Avoid writes to the underlying file by reading it all in memory and
+        // only operating on that.
+        auto mem_stream = std::make_unique<std::stringstream>();
+        std::ifstream temp(img_path, std::ios::in | std::ios::binary);
+        if (!temp) return false;
+        *mem_stream << temp.rdbuf();
+        impl->stream = std::move(mem_stream);
+    } else {
+        auto file_stream = std::make_unique<std::fstream>(img_path, std::ios::in | std::ios::out | std::ios::binary);
+        if (!file_stream->is_open()) return false;
+        impl->stream = std::move(file_stream);
+    }
+    return impl->stream && impl->stream->good();
 }
 
 void ImgFile::close()
 {
-    impl->stream.close();
+    impl->stream.reset();
 }
 
 uint64_t ImgFile::size() const
 {
-    impl->stream.seekg(0, impl->stream.end);
-    return impl->stream.tellg();
+    impl->stream->seekg(0, impl->stream->end);
+    return impl->stream->tellg();
 }
 
 uint64_t ImgFile::read(void* buf, uint64_t offset, uint64_t length) const
 {
-    impl->stream.seekg(offset, std::ios::beg);
-    impl->stream.read((char *)buf, length);
-    return impl->stream.gcount();
+    impl->stream->seekg(offset, std::ios::beg);
+    impl->stream->read((char *)buf, length);
+    return impl->stream->gcount();
 }
 
 uint64_t ImgFile::write(const void* buf, uint64_t offset, uint64_t length)
 {
-    impl->stream.seekg(offset, std::ios::beg);
-    impl->stream.write((const char *)buf, length);
-    return impl->stream.gcount();
+    impl->stream->seekg(offset, std::ios::beg);
+    impl->stream->write((const char *)buf, length);
+    return impl->stream->gcount();
 }