diff --git a/src/emu/machine/atadev.c b/src/emu/machine/atadev.c
index 73e2a63f61e..caad25745f4 100644
--- a/src/emu/machine/atadev.c
+++ b/src/emu/machine/atadev.c
@@ -12,6 +12,8 @@
 
 ata_device_interface::ata_device_interface(const machine_config &mconfig, device_t &device) :
 	m_irq_handler(device),
-	m_dmarq_handler(device)
+	m_dmarq_handler(device),
+	m_dasp_handler(device),
+	m_pdiag_handler(device)
 {
 }
diff --git a/src/emu/machine/atadev.h b/src/emu/machine/atadev.h
index bf5a7c92423..dd24b8239aa 100644
--- a/src/emu/machine/atadev.h
+++ b/src/emu/machine/atadev.h
@@ -34,9 +34,12 @@ public:
 	virtual DECLARE_WRITE_LINE_MEMBER(write_dmack) = 0;
 	virtual DECLARE_WRITE_LINE_MEMBER(write_csel) = 0;
 	virtual DECLARE_WRITE_LINE_MEMBER(write_dasp) = 0;
+	virtual DECLARE_WRITE_LINE_MEMBER(write_pdiag) = 0;
 
 	devcb2_write_line m_irq_handler;
 	devcb2_write_line m_dmarq_handler;
+	devcb2_write_line m_dasp_handler;
+	devcb2_write_line m_pdiag_handler;
 };
 
 #endif
diff --git a/src/emu/machine/ataintf.c b/src/emu/machine/ataintf.c
index 81b06ceece2..027a8ded646 100644
--- a/src/emu/machine/ataintf.c
+++ b/src/emu/machine/ataintf.c
@@ -14,24 +14,10 @@
 #include "debugger.h"
 #include "idehd.h"
 
-/***************************************************************************
-    DEBUGGING
-***************************************************************************/
-
-#define VERBOSE                     0
-
-#define LOG(x)  do { if (VERBOSE) logerror x; } while (0)
-
 void ata_interface_device::set_irq(int state)
 {
 //  printf( "irq %d\n", state );
 
-	if (state == ASSERT_LINE)
-		LOG(("ATA interrupt assert\n"));
-	else
-		LOG(("ATA interrupt clear\n"));
-
-	/* signal an interrupt */
 	m_irq_handler(state);
 }
 
@@ -42,6 +28,13 @@ void ata_interface_device::set_dmarq(int state)
 	m_dmarq_handler(state);
 }
 
+void ata_interface_device::set_dasp(int state)
+{
+//  printf( "dasp %d\n", state );
+
+	m_dasp_handler(state);
+}
+
 WRITE_LINE_MEMBER( ata_interface_device::irq0_write_line )
 {
 	if (m_irq[0] != state)
@@ -62,6 +55,30 @@ WRITE_LINE_MEMBER( ata_interface_device::irq1_write_line )
 	}
 }
 
+WRITE_LINE_MEMBER( ata_interface_device::dasp0_write_line )
+{
+	if (m_dasp[0] != state)
+	{
+		m_dasp[0] = state;
+
+		set_dasp(m_dasp[0] == ASSERT_LINE || m_dasp[1] == ASSERT_LINE);
+	}
+}
+
+WRITE_LINE_MEMBER( ata_interface_device::dasp1_write_line )
+{
+	if (m_dasp[1] != state)
+	{
+		m_dasp[1] = state;
+
+		ata_device_interface *dev = m_slot[0]->dev();
+		if (dev != NULL)
+			dev->write_dasp(state);
+
+		set_dasp(m_dasp[0] == ASSERT_LINE || m_dasp[1] == ASSERT_LINE);
+	}
+}
+
 WRITE_LINE_MEMBER( ata_interface_device::dmarq0_write_line )
 {
 	if (m_dmarq[0] != state)
@@ -82,6 +99,22 @@ WRITE_LINE_MEMBER( ata_interface_device::dmarq1_write_line )
 	}
 }
 
+WRITE_LINE_MEMBER( ata_interface_device::pdiag0_write_line )
+{
+	m_pdiag[0] = state;
+}
+
+WRITE_LINE_MEMBER( ata_interface_device::pdiag1_write_line )
+{
+	if (m_pdiag[1] != state)
+	{
+		m_pdiag[1] = state;
+
+		ata_device_interface *dev = m_slot[0]->dev();
+		if (dev != NULL)
+			dev->write_pdiag(state);
+	}
+}
 
 /*************************************
  *
@@ -174,8 +207,8 @@ SLOT_INTERFACE_END
 ata_interface_device::ata_interface_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, const char *shortname, const char *source) :
 	device_t(mconfig, type, name, tag, owner, clock, shortname, source),
 	m_irq_handler(*this),
-	m_dmarq_handler(*this)
-{
+	m_dmarq_handler(*this),
+	m_dasp_handler(*this){
 }
 
 
@@ -184,7 +217,8 @@ const device_type ATA_INTERFACE = &device_creator<ata_interface_device>;
 ata_interface_device::ata_interface_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
 	device_t(mconfig, ATA_INTERFACE, "ATA Interface", tag, owner, clock, "ata_interface", __FILE__),
 	m_irq_handler(*this),
-	m_dmarq_handler(*this)
+	m_dmarq_handler(*this),
+	m_dasp_handler(*this)
 {
 }
 
@@ -196,6 +230,7 @@ void ata_interface_device::device_start()
 {
 	m_irq_handler.resolve_safe();
 	m_dmarq_handler.resolve_safe();
+	m_dasp_handler.resolve_safe();
 
 	/* set MAME harddisk handle */
 	m_slot[0] = subdevice<ata_slot_device>("0");
@@ -205,6 +240,8 @@ void ata_interface_device::device_start()
 	{
 		m_irq[i] = 0;
 		m_dmarq[i] = 0;
+		m_dasp[i] = 0;
+		m_pdiag[i] = 0;
 
 		ata_device_interface *dev = m_slot[i]->dev();
 		if (dev != NULL)
@@ -213,30 +250,22 @@ void ata_interface_device::device_start()
 			{
 				dev->m_irq_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, irq0_write_line));
 				dev->m_dmarq_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, dmarq0_write_line));
+				dev->m_dasp_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, dasp0_write_line));
+				dev->m_pdiag_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, pdiag0_write_line));
 			}
 			else
 			{
 				dev->m_irq_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, irq1_write_line));
 				dev->m_dmarq_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, dmarq1_write_line));
+				dev->m_dasp_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, dasp1_write_line));
+				dev->m_pdiag_handler.set_callback(DEVCB2_DEVWRITELINE("^", ata_interface_device, pdiag1_write_line));
 			}
 
 			dev->write_csel(i);
-			dev->write_dasp(m_slot[1]->dev() != NULL);
 		}
 	}
 }
 
-//-------------------------------------------------
-//  device_reset - device-specific reset
-//-------------------------------------------------
-
-void ata_interface_device::device_reset()
-{
-	LOG(("ATA interface reset\n"));
-}
-
-
-
 //**************************************************************************
 //  ATA SLOT DEVICE
 //**************************************************************************
diff --git a/src/emu/machine/ataintf.h b/src/emu/machine/ataintf.h
index 369933e0029..be63a9e644e 100644
--- a/src/emu/machine/ataintf.h
+++ b/src/emu/machine/ataintf.h
@@ -51,6 +51,9 @@ extern const device_type ATA_SLOT;
 #define MCFG_ATA_INTERFACE_DMARQ_HANDLER(_devcb) \
 	devcb = &ata_interface_device::set_dmarq_handler(*device, DEVCB2_##_devcb);
 
+#define MCFG_ATA_INTERFACE_DASP_HANDLER(_devcb) \
+	devcb = &ata_interface_device::set_dasp_handler(*device, DEVCB2_##_devcb);
+
 SLOT_INTERFACE_EXTERN(ata_devices);
 
 /***************************************************************************
@@ -82,7 +85,7 @@ public:
 	// static configuration helpers
 	template<class _Object> static devcb2_base &set_irq_handler(device_t &device, _Object object) { return downcast<ata_interface_device &>(device).m_irq_handler.set_callback(object); }
 	template<class _Object> static devcb2_base &set_dmarq_handler(device_t &device, _Object object) { return downcast<ata_interface_device &>(device).m_dmarq_handler.set_callback(object); }
-
+	template<class _Object> static devcb2_base &set_dasp_handler(device_t &device, _Object object) { return downcast<ata_interface_device &>(device).m_dasp_handler.set_callback(object); }
 	UINT16 read_dma();
 	virtual DECLARE_READ16_MEMBER(read_cs0);
 	virtual DECLARE_READ16_MEMBER(read_cs1);
@@ -95,24 +98,31 @@ public:
 protected:
 	// device-level overrides
 	virtual void device_start();
-	virtual void device_reset();
 
 	virtual void set_irq(int state);
 	virtual void set_dmarq(int state);
+	virtual void set_dasp(int state);
 
 private:
 	DECLARE_WRITE_LINE_MEMBER(irq0_write_line);
 	DECLARE_WRITE_LINE_MEMBER(dmarq0_write_line);
+	DECLARE_WRITE_LINE_MEMBER(dasp0_write_line);
+	DECLARE_WRITE_LINE_MEMBER(pdiag0_write_line);
 
 	DECLARE_WRITE_LINE_MEMBER(irq1_write_line);
 	DECLARE_WRITE_LINE_MEMBER(dmarq1_write_line);
+	DECLARE_WRITE_LINE_MEMBER(dasp1_write_line);
+	DECLARE_WRITE_LINE_MEMBER(pdiag1_write_line);
 
 	ata_slot_device *m_slot[2];
 	int m_irq[2];
 	int m_dmarq[2];
+	int m_dasp[2];
+	int m_pdiag[2];
 
 	devcb2_write_line m_irq_handler;
 	devcb2_write_line m_dmarq_handler;
+	devcb2_write_line m_dasp_handler;
 };
 
 extern const device_type ATA_INTERFACE;
diff --git a/src/emu/machine/idehd.c b/src/emu/machine/idehd.c
index afab428d90a..616f845fc6a 100644
--- a/src/emu/machine/idehd.c
+++ b/src/emu/machine/idehd.c
@@ -16,10 +16,15 @@
 
 #define TIME_PER_SECTOR                     (attotime::from_usec(100))
 #define TIME_PER_ROTATION                   (attotime::from_hz(5400/60))
+#define TIME_MULTIPLE_SECTORS               (attotime::from_usec(1))
 
 #define TIME_SEEK_MULTISECTOR               (attotime::from_msec(13))
 #define TIME_NO_SEEK_MULTISECTOR            (attotime::from_nsec(16300))
 
+#define DIAGNOSTIC_TIME                     (attotime::from_msec(2))
+#define DETECT_DEVICE1_TIME                 (attotime::from_msec(2))
+#define DEVICE1_PDIAG_TIME                  (attotime::from_msec(2))
+
 #define IDE_CS0_DATA_RW              0
 #define IDE_CS0_ERROR_R              1
 #define IDE_CS0_FEATURE_W            1
@@ -63,11 +68,16 @@
 enum
 {
 	TID_NULL,
-	TID_DELAYED_INTERRUPT,
-	TID_DELAYED_INTERRUPT_BUFFER_READY,
-	TID_RESET_CALLBACK,
-	TID_READ_SECTOR_DONE_CALLBACK,
-	TID_WRITE_SECTOR_DONE_CALLBACK
+	TID_BUSY,
+};
+
+enum
+{
+	PARAM_RESET,
+	PARAM_DETECT_DEVICE1,
+	PARAM_DIAGNOSTIC,
+	PARAM_WAIT_FOR_PDIAG,
+	PARAM_COMMAND
 };
 
 ata_mass_storage_device::ata_mass_storage_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock,const char *shortname, const char *source)
@@ -76,10 +86,13 @@ ata_mass_storage_device::ata_mass_storage_device(const machine_config &mconfig,
 	device_slot_card_interface(mconfig, *this),
 	m_can_identify_device(0),
 	m_csel(0),
-	m_dasp(0),
+	m_daspin(0),
+	m_daspout(0),
 	m_dmack(0),
 	m_dmarq(0),
 	m_irq(0),
+	m_pdiagin(0),
+	m_pdiagout(0),
 	m_master_password(NULL),
 	m_user_password(NULL)
 {
@@ -118,6 +131,26 @@ void ata_mass_storage_device::set_dmarq(int state)
 	}
 }
 
+void ata_mass_storage_device::set_dasp(int state)
+{
+	if (m_daspout != state)
+	{
+		m_daspout = state;
+
+		m_dasp_handler(state);
+	}
+}
+
+void ata_mass_storage_device::set_pdiag(int state)
+{
+	if (m_pdiagout != state)
+	{
+		m_pdiagout = state;
+
+		m_pdiag_handler(state);
+	}
+}
+
 WRITE_LINE_MEMBER( ata_mass_storage_device::write_csel )
 {
 	m_csel = state;
@@ -125,7 +158,7 @@ WRITE_LINE_MEMBER( ata_mass_storage_device::write_csel )
 
 WRITE_LINE_MEMBER( ata_mass_storage_device::write_dasp )
 {
-	m_dasp = state;
+	m_daspin = state;
 }
 
 WRITE_LINE_MEMBER( ata_mass_storage_device::write_dmack )
@@ -133,6 +166,17 @@ WRITE_LINE_MEMBER( ata_mass_storage_device::write_dmack )
 	m_dmack = state;
 }
 
+WRITE_LINE_MEMBER( ata_mass_storage_device::write_pdiag )
+{
+	m_pdiagin = state;
+
+	if (m_pdiagin == ASSERT_LINE && m_busy_timer->param() == PARAM_WAIT_FOR_PDIAG)
+	{
+		stop_busy();
+		finished_diagnostic();
+	}
+}
+
 /*************************************
  *
  *  Compute the LBA address
@@ -334,6 +378,8 @@ void ata_mass_storage_device::device_start()
 {
 	m_irq_handler.resolve_safe();
 	m_dmarq_handler.resolve_safe();
+	m_dasp_handler.resolve_safe();
+	m_pdiag_handler.resolve_safe();
 
 	save_item(NAME(m_buffer));
 	save_item(NAME(m_buffer_offset));
@@ -360,10 +406,33 @@ void ata_mass_storage_device::device_start()
 
 	/* create a timer for timing status */
 	m_last_status_timer = timer_alloc(TID_NULL);
-	m_reset_timer = timer_alloc(TID_RESET_CALLBACK);
+	m_busy_timer = timer_alloc(TID_BUSY);
 }
 
 void ata_mass_storage_device::device_reset()
+{
+	/* reset the drive state */
+	set_dasp(CLEAR_LINE);
+	set_dmarq(CLEAR_LINE);
+	set_irq(CLEAR_LINE);
+	set_pdiag(CLEAR_LINE);
+
+	m_status = 0;
+	m_device_control = 0;
+	m_resetting = true;
+
+	if (m_csel == 0)
+	{
+		start_busy(DETECT_DEVICE1_TIME, PARAM_DETECT_DEVICE1);
+	}
+	else
+	{
+		set_dasp(ASSERT_LINE);
+		soft_reset();
+	}
+}
+
+void ata_mass_storage_device::soft_reset()
 {
 	m_buffer_offset = 0;
 	m_master_password_enable = (m_master_password != NULL);
@@ -376,50 +445,139 @@ void ata_mass_storage_device::device_reset()
 		m_status |= IDE_STATUS_DRDY;
 	}
 
+	start_busy(DIAGNOSTIC_TIME, PARAM_DIAGNOSTIC);
+}
+
+void ata_mass_storage_device::perform_diagnostic()
+{
 	if (m_can_identify_device)
+	{
 		m_error = IDE_ERROR_DIAGNOSTIC_PASSED;
+
+		if (m_csel == 1)
+			set_pdiag(ASSERT_LINE);
+	}
 	else
 		m_error = IDE_ERROR_DIAGNOSTIC_FAILED;
 
+	if (m_csel == 0 && !m_single_device && m_pdiagin == CLEAR_LINE)
+		start_busy(DEVICE1_PDIAG_TIME, PARAM_WAIT_FOR_PDIAG);
+	else
+		finished_diagnostic();
+}
+
+void ata_mass_storage_device::finished_diagnostic()
+{
 	m_sector_count = 1;
 	m_sector_number = 1;
 	m_cylinder_low = 0;
 	m_cylinder_high = 0;
 	m_device_head = 0;
 
-	/* reset the drive state */
-	set_irq(CLEAR_LINE);
-	set_dmarq(CLEAR_LINE);
+	m_resetting = false;
+}
+
+
+void ata_mass_storage_device::start_busy(attotime time, int param)
+{
+	m_status |= IDE_STATUS_BSY;
+	m_busy_timer->adjust(time, param);
+}
+
+void ata_mass_storage_device::stop_busy()
+{
+	m_status &= ~IDE_STATUS_BSY;
+	m_busy_timer->adjust(attotime::never);
 }
 
 void ata_mass_storage_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
 {
 	switch(id)
 	{
-	case TID_DELAYED_INTERRUPT:
+	case TID_BUSY:
 		m_status &= ~IDE_STATUS_BSY;
 
-		set_irq(ASSERT_LINE);
+		finished_busy(param);
+		break;
+	}
+}
+
+void ata_mass_storage_device::finished_busy(int param)
+{
+	switch (param)
+	{
+	case PARAM_DETECT_DEVICE1:
+		m_single_device = (m_daspin == CLEAR_LINE);
+		soft_reset();
 		break;
 
-	case TID_DELAYED_INTERRUPT_BUFFER_READY:
-		m_status &= ~IDE_STATUS_BSY;
-		m_status |= IDE_STATUS_DRQ;
-
-		set_irq(ASSERT_LINE);
+	case PARAM_DIAGNOSTIC:
+		perform_diagnostic();
 		break;
 
-	case TID_RESET_CALLBACK:
-		reset();
+	case PARAM_WAIT_FOR_PDIAG:
+		m_error |= 0x80;
+		finished_diagnostic();
 		break;
 
-	case TID_READ_SECTOR_DONE_CALLBACK:
-		read_sector_done();
-		break;
+	case PARAM_COMMAND:
+		switch (m_command)
+		{
+		case IDE_COMMAND_DIAGNOSTIC:
+			perform_diagnostic();
 
-	case TID_WRITE_SECTOR_DONE_CALLBACK:
-		write_sector_done();
-		break;
+			if (m_csel == 0)
+				set_irq(ASSERT_LINE);
+			break;
+
+		case IDE_COMMAND_IDENTIFY_DEVICE:
+			if (m_can_identify_device)
+			{
+				memcpy(m_buffer, m_identify_device, sizeof(m_buffer));
+				m_status |= IDE_STATUS_DRQ;
+			}
+			else
+			{
+				m_status |= IDE_STATUS_ERR;
+				m_error = IDE_ERROR_NONE;
+			}
+
+			set_irq(ASSERT_LINE);
+			break;
+
+		case IDE_COMMAND_SET_CONFIG:
+			set_geometry(m_sector_count,(m_device_head & IDE_DEVICE_HEAD_HS) + 1);
+			set_irq(ASSERT_LINE);
+			break;
+
+		case IDE_COMMAND_READ_SECTORS:
+		case IDE_COMMAND_READ_SECTORS_NORETRY:
+		case IDE_COMMAND_READ_MULTIPLE:
+		case IDE_COMMAND_VERIFY_SECTORS:
+		case IDE_COMMAND_VERIFY_SECTORS_NORETRY:
+		case IDE_COMMAND_READ_DMA:
+			read_sector_done();
+			break;
+
+		case IDE_COMMAND_WRITE_SECTORS:
+		case IDE_COMMAND_WRITE_SECTORS_NORETRY:
+		case IDE_COMMAND_WRITE_MULTIPLE:
+		case IDE_COMMAND_WRITE_DMA:
+			write_sector_done();
+			break;
+
+		case IDE_COMMAND_RECALIBRATE:
+			set_irq(ASSERT_LINE);
+			break;
+
+		case IDE_COMMAND_SET_FEATURES:
+			set_irq(ASSERT_LINE);
+			break;
+
+		default:
+			logerror( "finished_busy(%d) unhandled command %02x\n", param, m_command );
+			break;
+		}
 	}
 }
 
@@ -539,7 +697,7 @@ void ata_mass_storage_device::read_sector_done()
 {
 	int lba = lba_address(), count = 0;
 
-	m_status &= ~IDE_STATUS_BSY;
+	set_dasp(CLEAR_LINE);
 
 	/* now do the read */
 	count = read_sector(lba, m_buffer);
@@ -589,8 +747,7 @@ void ata_mass_storage_device::read_sector_done()
 
 void ata_mass_storage_device::read_first_sector()
 {
-	/* mark ourselves busy */
-	m_status |= IDE_STATUS_BSY;
+	set_dasp(ASSERT_LINE);
 
 	/* just set a timer */
 	if (m_command == IDE_COMMAND_READ_MULTIPLE)
@@ -599,22 +756,20 @@ void ata_mass_storage_device::read_first_sector()
 		attotime seek_time;
 
 		if (new_lba == m_cur_lba || new_lba == m_cur_lba + 1)
-			seek_time = TIME_NO_SEEK_MULTISECTOR;
+			start_busy(TIME_NO_SEEK_MULTISECTOR, PARAM_COMMAND);
 		else
-			seek_time = TIME_SEEK_MULTISECTOR;
+			start_busy(TIME_SEEK_MULTISECTOR, PARAM_COMMAND);
 
 		m_cur_lba = new_lba;
-		timer_set(seek_time, TID_READ_SECTOR_DONE_CALLBACK);
 	}
 	else
-		timer_set(TIME_PER_SECTOR, TID_READ_SECTOR_DONE_CALLBACK);
+		start_busy(TIME_PER_SECTOR, PARAM_COMMAND);
 }
 
 
 void ata_mass_storage_device::read_next_sector()
 {
-	/* mark ourselves busy */
-	m_status |= IDE_STATUS_BSY;
+	set_dasp(ASSERT_LINE);
 
 	if (m_command == IDE_COMMAND_READ_MULTIPLE)
 	{
@@ -622,12 +777,10 @@ void ata_mass_storage_device::read_next_sector()
 			/* make ready now */
 			read_sector_done();
 		else
-			/* just set a timer */
-			timer_set(attotime::from_usec(1), TID_READ_SECTOR_DONE_CALLBACK);
+			start_busy(TIME_MULTIPLE_SECTORS, PARAM_COMMAND);
 	}
 	else
-		/* just set a timer */
-		timer_set(TIME_PER_SECTOR, TID_READ_SECTOR_DONE_CALLBACK);
+		start_busy(TIME_PER_SECTOR, PARAM_COMMAND);
 }
 
 
@@ -643,8 +796,7 @@ void ata_mass_storage_device::continue_write()
 	/* reset the totals */
 	m_buffer_offset = 0;
 
-	/* clear the buffer ready flag */
-	m_status |= IDE_STATUS_BSY;
+	set_dasp(ASSERT_LINE);
 
 	if (m_command == IDE_COMMAND_WRITE_MULTIPLE)
 	{
@@ -656,13 +808,13 @@ void ata_mass_storage_device::continue_write()
 		else
 		{
 			/* set a timer to do the write */
-			timer_set(TIME_PER_SECTOR, TID_WRITE_SECTOR_DONE_CALLBACK);
+			start_busy(TIME_PER_SECTOR, PARAM_COMMAND);
 		}
 	}
 	else
 	{
 		/* set a timer to do the write */
-		timer_set(TIME_PER_SECTOR, TID_WRITE_SECTOR_DONE_CALLBACK);
+		start_busy(TIME_PER_SECTOR, PARAM_COMMAND);
 	}
 }
 
@@ -718,7 +870,7 @@ void ata_mass_storage_device::write_sector_done()
 {
 	int lba = lba_address(), count = 0;
 
-	m_status &= ~IDE_STATUS_BSY;
+	set_dasp(CLEAR_LINE);
 
 	/* now do the write */
 	count = write_sector(lba, m_buffer);
@@ -867,34 +1019,15 @@ bool ata_mass_storage_device::process_command()
 	case IDE_COMMAND_IDENTIFY_DEVICE:
 		LOGPRINT(("IDE Identify device\n"));
 
-		m_status |= IDE_STATUS_BSY;
-		if (m_can_identify_device)
-		{
-			memcpy(m_buffer, m_identify_device, sizeof(m_buffer));
-
-			timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT_BUFFER_READY);
-		}
-		else
-		{
-			m_status |= IDE_STATUS_ERR;
-			m_error = IDE_ERROR_NONE;
-			timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT);
-		}
+		start_busy(MINIMUM_COMMAND_TIME, PARAM_COMMAND);
 		return true;
 
 	case IDE_COMMAND_DIAGNOSTIC:
-		if (m_can_identify_device)
-			m_error = IDE_ERROR_DIAGNOSTIC_PASSED;
-		else
-			m_error = IDE_ERROR_DIAGNOSTIC_FAILED;
-
-		m_status |= IDE_STATUS_BSY;
-		timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT);
+		start_busy(DIAGNOSTIC_TIME, PARAM_COMMAND);
 		return true;
 
 	case IDE_COMMAND_RECALIBRATE:
-		m_status |= IDE_STATUS_BSY;
-		timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT);
+		start_busy(MINIMUM_COMMAND_TIME, PARAM_COMMAND);
 		return true;
 
 	case IDE_COMMAND_IDLE:
@@ -904,10 +1037,8 @@ bool ata_mass_storage_device::process_command()
 
 	case IDE_COMMAND_SET_CONFIG:
 		LOGPRINT(("IDE Set configuration (%d heads, %d sectors)\n", (m_device_head & IDE_DEVICE_HEAD_HS) + 1, m_sector_count));
-		set_geometry(m_sector_count,(m_device_head & IDE_DEVICE_HEAD_HS) + 1);
 
-		m_status |= IDE_STATUS_BSY;
-		timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT);
+		start_busy(MINIMUM_COMMAND_TIME, PARAM_COMMAND);
 		return true;
 
 	case IDE_COMMAND_SET_MAX:
@@ -920,8 +1051,7 @@ bool ata_mass_storage_device::process_command()
 	case IDE_COMMAND_SET_FEATURES:
 		LOGPRINT(("IDE Set features (%02X %02X %02X %02X %02X)\n", m_feature, m_sector_count & 0xff, m_sector_number, m_cylinder_low, m_cylinder_high));
 
-		m_status |= IDE_STATUS_BSY;
-		timer_set(MINIMUM_COMMAND_TIME, TID_DELAYED_INTERRUPT);
+		start_busy(MINIMUM_COMMAND_TIME, PARAM_COMMAND);
 		return true;
 
 	case IDE_COMMAND_SET_BLOCK_COUNT:
@@ -989,7 +1119,7 @@ READ16_MEMBER( ata_mass_storage_device::read_cs0 )
 
 	UINT16 result = 0xffff;
 
-	if (device_selected() || single_device())
+	if (device_selected() || m_single_device)
 	{
 		if (m_dmack)
 		{
@@ -997,6 +1127,8 @@ READ16_MEMBER( ata_mass_storage_device::read_cs0 )
 		}
 		else if ((m_status & IDE_STATUS_BSY) && offset != IDE_CS0_STATUS_R)
 		{
+			// ATA5 spec says status reads should also go through here, but this breaks Primal Rage 2.
+			// Real hardware might work due to read ahead in the vt83c461.
 			if (device_selected())
 			{
 				switch (offset)
@@ -1093,9 +1225,7 @@ READ16_MEMBER( ata_mass_storage_device::read_cs0 )
 						}
 
 						if (!(m_status & IDE_STATUS_DRDY) && is_ready())
-						{
 							m_status |= IDE_STATUS_DRDY;
-						}
 
 						set_irq(CLEAR_LINE);
 					}
@@ -1125,7 +1255,7 @@ READ16_MEMBER( ata_mass_storage_device::read_cs1 )
 
 	UINT16 result = 0xffff;
 
-	if (device_selected() || single_device())
+	if (device_selected() || m_single_device)
 	{
 		if (m_dmack)
 		{
@@ -1212,7 +1342,7 @@ WRITE16_MEMBER( ata_mass_storage_device::write_cs0 )
 	}
 	else if ((m_status & IDE_STATUS_BSY) && offset != IDE_CS0_COMMAND_W)
 	{
-		logerror( "%s: dev %d write_cs0 %04x %04x %04x ignored (BSY)\n", machine().describe_context(), dev(), offset, data, mem_mask );
+		logerror( "%s: dev %d write_cs0 %04x %04x %04x ignored (BSY) command %02x\n", machine().describe_context(), dev(), offset, data, mem_mask, m_command );
 	}
 	else if ((m_status & IDE_STATUS_DRQ) && offset != IDE_CS0_DATA_RW && offset != IDE_CS0_COMMAND_W)
 	{
@@ -1284,10 +1414,19 @@ WRITE16_MEMBER( ata_mass_storage_device::write_cs0 )
 
 			/* command */
 			case IDE_CS0_COMMAND_W:
-				m_command = data;
-
-				if (device_selected() || m_command == IDE_COMMAND_DIAGNOSTIC)
+				// Packet devices can accept DEVICE RESET when BSY or DRQ is set.
+				if (m_status & IDE_STATUS_BSY)
 				{
+					logerror( "%s: dev %d write_cs0 %04x %04x %04x ignored (BSY) command %02x\n", machine().describe_context(), dev(), offset, data, mem_mask, m_command );
+				}
+				else if (m_status & IDE_STATUS_DRQ)
+				{
+					logerror( "%s: dev %d write_cs0 %04x %04x %04x ignored (DRQ) command %02x\n", machine().describe_context(), dev(), offset, data, mem_mask, m_command );
+				}
+				else if (device_selected() || m_command == IDE_COMMAND_DIAGNOSTIC)
+				{
+					m_command = data;
+
 					/* implicitly clear interrupts & dmarq here */
 					set_irq(CLEAR_LINE);
 					set_dmarq(CLEAR_LINE);
@@ -1295,7 +1434,7 @@ WRITE16_MEMBER( ata_mass_storage_device::write_cs0 )
 					m_buffer_offset = 0;
 					m_sectors_until_int = 0;
 
-					m_status &= ~IDE_STATUS_BSY;
+					set_dasp(CLEAR_LINE);
 					m_status &= ~IDE_STATUS_DRQ;
 					m_status &= ~IDE_STATUS_ERR;
 
@@ -1344,9 +1483,23 @@ WRITE16_MEMBER( ata_mass_storage_device::write_cs1 )
 				{
 					if (m_device_control & IDE_DEVICE_CONTROL_SRST)
 					{
-						m_status |= IDE_STATUS_BSY;
-						set_irq(CLEAR_LINE);
-						m_reset_timer->adjust(attotime::from_msec(5));
+						if (m_resetting)
+						{
+							logerror( "%s: dev %d write_cs1 %04x %04x %04x ignored (RESET)\n", machine().describe_context(), dev(), offset, data, mem_mask );
+						}
+						else
+						{
+							set_dasp(CLEAR_LINE);
+							set_dmarq(CLEAR_LINE);
+							set_irq(CLEAR_LINE);
+							set_pdiag(CLEAR_LINE);
+
+							start_busy(attotime::never, PARAM_RESET);
+						}
+					}
+					else if (m_busy_timer->param() == PARAM_RESET)
+					{
+						soft_reset();
 					}
 				}
 				break;
diff --git a/src/emu/machine/idehd.h b/src/emu/machine/idehd.h
index e59c43e416f..3ca8285a16b 100644
--- a/src/emu/machine/idehd.h
+++ b/src/emu/machine/idehd.h
@@ -61,6 +61,7 @@ public:
 	virtual DECLARE_WRITE_LINE_MEMBER(write_csel);
 	virtual DECLARE_WRITE_LINE_MEMBER(write_dasp);
 	virtual DECLARE_WRITE_LINE_MEMBER(write_dmack);
+	virtual DECLARE_WRITE_LINE_MEMBER(write_pdiag);
 
 	UINT8 *identify_device_buffer() { return m_identify_device; }
 
@@ -88,15 +89,17 @@ protected:
 
 	int dev() { return (m_device_head & IDE_DEVICE_HEAD_DRV) >> 4; }
 	bool device_selected() { return m_csel == dev(); }
-	bool single_device() { return m_csel == 0 && m_dasp == 0; }
 
 	void set_irq(int state);
 	void set_dmarq(int state);
+	void set_dasp(int state);
+	void set_pdiag(int state);
 	void ide_build_identify_device();
 
 	virtual bool process_command();
 	virtual void process_buffer();
 	virtual void fill_buffer();
+	virtual void finished_busy(int param);
 
 	UINT8           m_buffer[IDE_DISK_SECTOR_SIZE];
 	UINT16          m_buffer_offset;
@@ -131,12 +134,23 @@ private:
 	void read_buffer_empty();
 	void write_buffer_full();
 	void update_irq();
+	void start_busy(attotime time, int param);
+	void stop_busy();
+	void soft_reset();
+	void perform_diagnostic();
+	void finished_diagnostic();
 
 	int m_csel;
-	int m_dasp;
+	int m_daspin;
+	int m_daspout;
 	int m_dmack;
 	int m_dmarq;
 	int m_irq;
+	int m_pdiagin;
+	int m_pdiagout;
+
+	bool m_resetting;
+	bool m_single_device;
 
 	UINT32          m_cur_lba;
 	UINT16          m_block_count;
@@ -148,7 +162,7 @@ private:
 	const UINT8 *   m_user_password;
 
 	emu_timer *     m_last_status_timer;
-	emu_timer *     m_reset_timer;
+	emu_timer *     m_busy_timer;
 };
 
 // ======================> ide_hdd_device
diff --git a/src/mame/drivers/viper.c b/src/mame/drivers/viper.c
index e24ee5ed0b9..8322639daa2 100644
--- a/src/mame/drivers/viper.c
+++ b/src/mame/drivers/viper.c
@@ -1419,8 +1419,7 @@ WRITE64_MEMBER(viper_state::cf_card_w)
 					{
 						m_cf_card_ide = 1;
 
-						// soft reset
-						m_ata->write_cs1(space, 6, 0x04, 0xff);
+						m_ata->reset();
 					}
 					break;
 				}
diff --git a/src/mess/machine/a2cffa.c b/src/mess/machine/a2cffa.c
index 6bfda7e6f93..b6db86a79eb 100644
--- a/src/mess/machine/a2cffa.c
+++ b/src/mess/machine/a2cffa.c
@@ -32,7 +32,7 @@ const device_type A2BUS_CFFA2_6502 = &device_creator<a2bus_cffa2_6502_device>;
 #define CFFA2_ATA_TAG     "cffa2_ata"
 
 MACHINE_CONFIG_FRAGMENT( cffa2 )
-	MCFG_ATA_INTERFACE_ADD(CFFA2_ATA_TAG, ata_devices, "hdd", "hdd", false)
+	MCFG_ATA_INTERFACE_ADD(CFFA2_ATA_TAG, ata_devices, "hdd", NULL, false)
 MACHINE_CONFIG_END
 
 ROM_START( cffa2 )
diff --git a/src/mess/machine/a2vulcan.c b/src/mess/machine/a2vulcan.c
index 662b48c8e25..94d51c2fcc7 100644
--- a/src/mess/machine/a2vulcan.c
+++ b/src/mess/machine/a2vulcan.c
@@ -66,7 +66,7 @@ const device_type A2BUS_VULCAN = &device_creator<a2bus_vulcan_device>;
 #define VULCAN_ATA_TAG     "vulcan_ata"
 
 static MACHINE_CONFIG_FRAGMENT( vulcan )
-	MCFG_ATA_INTERFACE_ADD(VULCAN_ATA_TAG, ata_devices, "hdd", "hdd", false)
+	MCFG_ATA_INTERFACE_ADD(VULCAN_ATA_TAG, ata_devices, "hdd", NULL, false)
 MACHINE_CONFIG_END
 
 ROM_START( vulcan )
diff --git a/src/mess/machine/a2zipdrive.c b/src/mess/machine/a2zipdrive.c
index 48c8ca9f243..2441856c2ab 100644
--- a/src/mess/machine/a2zipdrive.c
+++ b/src/mess/machine/a2zipdrive.c
@@ -32,7 +32,7 @@ const device_type A2BUS_ZIPDRIVE = &device_creator<a2bus_zipdrive_device>;
 #define ZIPDRIVE_ATA_TAG     "zipdrive_ata"
 
 static MACHINE_CONFIG_FRAGMENT( zipdrive )
-	MCFG_ATA_INTERFACE_ADD(ZIPDRIVE_ATA_TAG, ata_devices, "hdd", "hdd", false)
+	MCFG_ATA_INTERFACE_ADD(ZIPDRIVE_ATA_TAG, ata_devices, "hdd", NULL, false)
 MACHINE_CONFIG_END
 
 ROM_START( zipdrive )
diff --git a/src/mess/machine/c64_ide64.c b/src/mess/machine/c64_ide64.c
index 82806f1829c..060ad4de8f1 100644
--- a/src/mess/machine/c64_ide64.c
+++ b/src/mess/machine/c64_ide64.c
@@ -49,7 +49,7 @@ static MACHINE_CONFIG_FRAGMENT( c64_ide64 )
 	MCFG_ATMEL_29C010_ADD(AT29C010A_TAG)
 	MCFG_DS1302_ADD(DS1302_TAG, XTAL_32_768kHz)
 
-	MCFG_ATA_INTERFACE_ADD(ATA_TAG, ata_devices, "hdd", "hdd", false)
+	MCFG_ATA_INTERFACE_ADD(ATA_TAG, ata_devices, "hdd", NULL, false)
 MACHINE_CONFIG_END
 
 
diff --git a/src/mess/machine/isa_ide.c b/src/mess/machine/isa_ide.c
index c2fd92e2db0..0e29f43c0b8 100644
--- a/src/mess/machine/isa_ide.c
+++ b/src/mess/machine/isa_ide.c
@@ -40,7 +40,7 @@ WRITE_LINE_MEMBER(isa16_ide_device::ide_interrupt)
 }
 
 static MACHINE_CONFIG_FRAGMENT( ide )
-	MCFG_IDE_CONTROLLER_ADD("ide", ata_devices, "hdd", "hdd", false)
+	MCFG_IDE_CONTROLLER_ADD("ide", ata_devices, "hdd", NULL, false)
 	MCFG_ATA_INTERFACE_IRQ_HANDLER(WRITELINE(isa16_ide_device, ide_interrupt))
 MACHINE_CONFIG_END
 
diff --git a/src/mess/machine/isa_ide8.c b/src/mess/machine/isa_ide8.c
index fc73c5bfc95..48230a78022 100644
--- a/src/mess/machine/isa_ide8.c
+++ b/src/mess/machine/isa_ide8.c
@@ -114,7 +114,7 @@ WRITE_LINE_MEMBER(isa8_ide_device::ide_interrupt)
 }
 
 static MACHINE_CONFIG_FRAGMENT( ide8_config )
-	MCFG_IDE_CONTROLLER_ADD("ide", ata_devices, "hdd", "hdd", false)
+	MCFG_IDE_CONTROLLER_ADD("ide", ata_devices, "hdd", NULL, false)
 	MCFG_ATA_INTERFACE_IRQ_HANDLER(WRITELINE(isa8_ide_device, ide_interrupt))
 MACHINE_CONFIG_END
 
diff --git a/src/mess/machine/kc_d004.c b/src/mess/machine/kc_d004.c
index 4ac2acbb243..9359d7fabf9 100644
--- a/src/mess/machine/kc_d004.c
+++ b/src/mess/machine/kc_d004.c
@@ -90,7 +90,7 @@ static MACHINE_CONFIG_FRAGMENT(kc_d004_gide)
 	MCFG_CPU_MODIFY(Z80_TAG)
 	MCFG_CPU_IO_MAP(kc_d004_gide_io)
 
-	MCFG_ATA_INTERFACE_ADD(ATA_TAG, ata_devices, "hdd", "hdd", false)
+	MCFG_ATA_INTERFACE_ADD(ATA_TAG, ata_devices, "hdd", NULL, false)
 MACHINE_CONFIG_END