diff --git a/src/devices/bus/isa/omti8621.c b/src/devices/bus/isa/omti8621.c
index 96b1214ff85..fdb11304f5c 100644
--- a/src/devices/bus/isa/omti8621.c
+++ b/src/devices/bus/isa/omti8621.c
@@ -215,7 +215,8 @@ MACHINE_CONFIG_FRAGMENT( omti_disk )
 	MCFG_PC_FDC_INTRQ_CALLBACK(WRITELINE(omti8621_device, fdc_irq_w))
 	MCFG_PC_FDC_DRQ_CALLBACK(WRITELINE(omti8621_device, fdc_drq_w))
 	MCFG_FLOPPY_DRIVE_ADD(OMTI_FDC_TAG":0", pc_hd_floppies, "525hd", omti8621_device::floppy_formats)
-	MCFG_FLOPPY_DRIVE_ADD(OMTI_FDC_TAG":1", pc_hd_floppies, "525hd", omti8621_device::floppy_formats)
+// Apollo workstations never have more then 1 floppy drive
+//	MCFG_FLOPPY_DRIVE_ADD(OMTI_FDC_TAG":1", pc_hd_floppies, "525hd", omti8621_device::floppy_formats)
 MACHINE_CONFIG_END
 
 FLOPPY_FORMATS_MEMBER( omti8621_device::floppy_formats )
@@ -231,8 +232,12 @@ ROM_START( omti8621 )
 	ROM_REGION(0x4000, OMTI_CPU_REGION, 0)  // disassembles fine as Z8 code
 	ROM_LOAD( "omti_8621_102640-b.bin", 0x000000, 0x004000, CRC(e6f20dbb) SHA1(cf1990ad72eac6b296485410f5fa3309a0d6d078) )
 
+#if 1
+	// OMTI 8621 boards for Apollo workstations never use a BIOS ROM
+	// They don't even have a socket for the BIOS ROM
 	ROM_REGION(0x1000, OMTI_BIOS_REGION, 0)
-	ROM_LOAD("omti_bios", 0x0000, 0x1000, NO_DUMP)
+	ROM_LOAD_OPTIONAL("omti_bios", 0x0000, 0x1000, NO_DUMP)
+#endif
 ROM_END
 
 static INPUT_PORTS_START( omti_port )
@@ -280,6 +285,8 @@ ioport_constructor omti8621_device::device_input_ports() const
 
 void omti8621_device::device_start()
 {
+	LOG2(("device_start"));
+
 	set_isa_device();
 
 	m_installed = false;
@@ -300,7 +307,7 @@ void omti8621_device::device_reset()
 {
 	static const int io_bases[8] = { 0x320, 0x324, 0x328, 0x32c, 0x1a0, 0x1a4, 0x1a8, 0x1ac };
 
-	LOG2(("device_reset_omti8621"));
+	LOG2(("device_reset"));
 
 	// you can't read I/O ports in device_start() even if they're required_ioport<> in your class!
 	if (!m_installed)
@@ -1201,11 +1208,13 @@ void omti8621_device::set_verbose(int on_off)
  get_sector - get sector diskaddr of logical unit lun into data_buffer
  ***************************************************************************/
 
+// FIXME: this will work, but is not supported by MESS
+#if 0 // APOLLO_XXL
 UINT32 omti8621_device::get_sector(INT32 diskaddr, UINT8 *data_buffer, UINT32 length, UINT8 lun)
 {
-	omti_disk_image_device *disk = our_disks[lun];
+	omti_disk_image_device *disk = omti8621_device_1->our_disks[lun];
 
-	if (disk->m_image == NULL || !disk->m_image->exists())
+	if (disk == NULL || disk->m_image == NULL || !disk->m_image->exists())
 	{
 		return 0;
 	}
@@ -1222,7 +1231,7 @@ UINT32 omti8621_device::get_sector(INT32 diskaddr, UINT8 *data_buffer, UINT32 le
 		return length;
 	}
 }
-
+#endif
 
 /***************************************************************************
  omti_set_jumper - set OMI jumpers
diff --git a/src/devices/bus/isa/omti8621.h b/src/devices/bus/isa/omti8621.h
index 1a49a8e3993..d08ad8fdb41 100644
--- a/src/devices/bus/isa/omti8621.h
+++ b/src/devices/bus/isa/omti8621.h
@@ -42,7 +42,7 @@ public:
 	static void set_verbose(int on_off);
 
 	// get sector diskaddr of logical unit lun into data_buffer
-	UINT32 get_sector(INT32 diskaddr, UINT8 *data_buffer, UINT32 length, UINT8 lun);
+	static UINT32 get_sector(INT32 diskaddr, UINT8 *data_buffer, UINT32 length, UINT8 lun);
 
 	required_device<pc_fdc_interface> m_fdc;
 	required_ioport m_iobase;
diff --git a/src/devices/machine/mc146818.c b/src/devices/machine/mc146818.c
index 1509e7586e9..6870d2709c2 100644
--- a/src/devices/machine/mc146818.c
+++ b/src/devices/machine/mc146818.c
@@ -206,9 +206,9 @@ void mc146818_device::nvram_default()
 	}
 
 	if(m_binary)
-		m_data[0x0b] |= REG_B_DM;
+		m_data[REG_B] |= REG_B_DM;
 	if(m_hour)
-		m_data[0x0b] |= REG_B_24_12;
+		m_data[REG_B] |= REG_B_24_12;
 
 	set_base_datetime();
 	update_timer();
@@ -402,7 +402,7 @@ void mc146818_device::set_base_datetime()
 	set_dayofweek(current_time.weekday + 1);
 	set_dayofmonth(current_time.mday);
 	set_month(current_time.month + 1);
-	set_year((current_time.year - m_epoch) % (m_data[0x0b] & REG_B_DM ? 0x100 : 100));
+	set_year((current_time.year - m_epoch) % 100);
 
 	if (m_century_index >= 0)
 		m_data[m_century_index] = to_ram(current_time.year / 100);
diff --git a/src/lib/formats/apollo_dsk.c b/src/lib/formats/apollo_dsk.c
index 2770122a5c9..74ac0372a85 100644
--- a/src/lib/formats/apollo_dsk.c
+++ b/src/lib/formats/apollo_dsk.c
@@ -45,3 +45,12 @@ const apollo_format::format apollo_format::formats[] = {
 };
 
 const floppy_format_type FLOPPY_APOLLO_FORMAT = &floppy_image_format_creator<apollo_format>;
+
+int apollo_format::identify(io_generic *io, UINT32 form_factor)
+{
+	UINT64 size = io_generic_size(io);
+	UINT32 expected_size = 77*2*8*1024;
+
+	return ((size == expected_size) || (size == 0)) ? 1 : 0;
+}
+
diff --git a/src/lib/formats/apollo_dsk.h b/src/lib/formats/apollo_dsk.h
index 180787f2453..05013d79055 100644
--- a/src/lib/formats/apollo_dsk.h
+++ b/src/lib/formats/apollo_dsk.h
@@ -17,6 +17,7 @@ class apollo_format : public upd765_format {
 public:
 	apollo_format();
 
+	virtual int identify(io_generic *io, UINT32 form_factor);
 	virtual const char *name() const;
 	virtual const char *description() const;
 	virtual const char *extensions() const;
diff --git a/src/mame/drivers/apollo.c b/src/mame/drivers/apollo.c
index 1c41ed2c7d9..670950d03eb 100644
--- a/src/mame/drivers/apollo.c
+++ b/src/mame/drivers/apollo.c
@@ -109,11 +109,6 @@ static int parity_error_handler_install_counter = 0;
 static UINT16 latch_page_on_parity_error_register = 0x0000;
 static UINT16 master_req_register = 0x0000;
 
-// DN3000: Node Id 1D117 at 0x9600 - 0x961f
-// DN3500: Node Id 2616D at 0x11200 - 0x1121f
-
-static UINT32 node_id = DEFAULT_NODE_ID;
-
 static UINT32 ram_base_address;
 static UINT32 ram_end_address;
 
@@ -210,14 +205,6 @@ UINT8 apollo_get_ram_config_byte(void) {
 	return ram_config_byte;
 }
 
-/***************************************************************************
- apollo_get_node_id - get the node id
- ***************************************************************************/
-
-UINT32 apollo_get_node_id(void) {
-	return node_id;
-}
-
 /***************************************************************************
   apollo_instruction_hook
   must be called by the CPU core before executing each instruction
@@ -351,38 +338,6 @@ READ8_MEMBER(apollo_state::task_alias_register_r){
 	return data;
 }
 
-/***************************************************************************
- DN3000/DN3500 Node Id PROM at 0x9600/0x11200
- ***************************************************************************/
-
-WRITE16_MEMBER(apollo_state::apollo_node_id_w){
-	SLOG1(("Error: writing node id ROM at offset %02x = %04x & %04x", offset, data, mem_mask));
-}
-
-READ16_MEMBER(apollo_state::apollo_node_id_r){
-	UINT16 data;
-	switch (offset & 0x0f) {
-	case 1: // msb
-		data = (node_id >> 16) & 0xff;
-		break;
-	case 2:
-		data = (node_id >> 8) & 0xff;
-		break;
-	case 3: // lsb
-		data = node_id & 0xff;
-		break;
-	case 15: // checksum
-		data = ((node_id >> 16) + (node_id >> 8) + node_id) & 0xff;
-		break;
-	default:
-		data = 0;
-		break;
-	}
-	data <<= 8;
-	SLOG2(("reading node id ROM at offset %02x = %04x & %04x", offset, data, mem_mask));
-	return data;
-}
-
 /***************************************************************************
  DN3000/DN3500 Latch Page on Parity Error Register at 0x9300/0x11300
  ***************************************************************************/
@@ -576,7 +531,7 @@ READ16_MEMBER(apollo_state::apollo_atbus_io_r)
 	// Motorola CPU is MSB first, ISA Bus is LSB first
 	UINT16 data = m_isa->io16_swap_r(space, isa_addr, mem_mask);
 
-	SLOG2(("apollo_atbus_io_r at %08x -> %04x = %04x & %04x", offset*2, isa_addr*2, data, mem_mask));
+	SLOG2(("apollo_atbus_io_r at %08x -> %04x = %04x & %04x", ATBUS_IO_BASE + offset*2, isa_addr*2, data, mem_mask));
 
 	return data;
 }
@@ -585,7 +540,7 @@ WRITE16_MEMBER(apollo_state::apollo_atbus_io_w)
 {
 	UINT32 isa_addr = (offset & 3) + ((offset & ~0x1ff) >> 7);
 
-	SLOG2(("apollo_atbus_io_w at %08x -> %04x = %04x & %04x", offset*2, isa_addr*2, data, mem_mask));
+	SLOG2(("apollo_atbus_io_w at %08x -> %04x = %04x & %04x", ATBUS_IO_BASE + offset*2, isa_addr*2, data, mem_mask));
 
 	// Motorola CPU is MSB first, ISA Bus is LSB first
 	m_isa->io16_swap_w(space, isa_addr, data, mem_mask);
@@ -597,22 +552,55 @@ WRITE16_MEMBER(apollo_state::apollo_atbus_io_w)
 
 READ16_MEMBER(apollo_state::apollo_atbus_memory_r)
 {
+	UINT16 data;
+
 	// Motorola CPU is MSB first, ISA Bus is LSB first
-	UINT16 data = m_isa->prog16_swap_r(space, offset, mem_mask);
-
-	SLOG2(("apollo_atbus_memory_r at %08x = %04x & %04x", offset*2, data, mem_mask));
+	data = m_isa->prog16_swap_r(space, offset, mem_mask);
 
+	SLOG2(("apollo_atbus_memory_r at %08x = %04x & %04x", ATBUS_MEMORY_BASE + offset * 2, data, mem_mask));
 	return data;
 }
 
 WRITE16_MEMBER(apollo_state::apollo_atbus_memory_w)
 {
-	SLOG2(("apollo_atbus_memory_w at %08x = %04x & %04x", offset*2, data, mem_mask));
+	SLOG2(("apollo_atbus_memory_w at %08x = %04x & %04x", ATBUS_MEMORY_BASE + offset*2, data, mem_mask));
 
 	// Motorola CPU is MSB first, ISA Bus is LSB first
 	m_isa->prog16_swap_w(space, offset, data, mem_mask);
 }
 
+/***************************************************************************
+ DN3000/DN3500 AT Bus unmapped read/write
+ ***************************************************************************/
+
+READ16_MEMBER(apollo_state::apollo_atbus_unmap_io_r)
+{
+	// ISA bus has 0xff for unmapped addresses
+	UINT16 data = 0xffff;
+	UINT32 isa_addr = (offset & 3) + ((offset & ~0x1ff) >> 7);
+	SLOG1(("apollo_atbus_unmap_io_r at %08x -> %04x = %04x & %04x", ATBUS_IO_BASE + offset*2, isa_addr*2, data, mem_mask));
+	return data;
+}
+
+WRITE16_MEMBER(apollo_state::apollo_atbus_unmap_io_w)
+{
+	UINT32 isa_addr = (offset & 3) + ((offset & ~0x1ff) >> 7);
+	SLOG1(("apollo_atbus_unmap_io_w at %08x -> %04x = %04x & %04x", ATBUS_IO_BASE + offset*2, isa_addr*2, data, mem_mask));
+}
+
+READ8_MEMBER(apollo_state::apollo_atbus_unmap_r)
+{
+	// ISA bus has 0xff for unmapped addresses
+	UINT8 data = 0xff;
+	SLOG2(("apollo_atbus_unmap_r at %08x = %02x & %02x", ATBUS_MEMORY_BASE + offset, data, mem_mask));
+	return data;
+}
+
+WRITE8_MEMBER(apollo_state::apollo_atbus_unmap_w)
+{
+	SLOG1(("apollo_atbus_unmap_w at %08x = %02x & %02x", ATBUS_MEMORY_BASE + offset, data, mem_mask));
+}
+
 /***************************************************************************
  DN5500 Memory Present Register at 0x11400-0x114ff
  Strange: documented but not used
@@ -697,7 +685,7 @@ static ADDRESS_MAP_START(dn3500_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x010d00, 0x010dff) AM_READWRITE8(/*"dma2",*/apollo_dma_2_r, apollo_dma_2_w, 0xffffffff )
 		AM_RANGE(0x011000, 0x0110ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x011100, 0x0111ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x011200, 0x0112ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x011200, 0x0112ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 		AM_RANGE(0x011300, 0x0113ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x011600, 0x0116ff) AM_READWRITE8(master_req_register_r, master_req_register_w, 0xffffffff)
 
@@ -741,7 +729,7 @@ static ADDRESS_MAP_START(dsp3500_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x010d00, 0x010dff) AM_READWRITE8(/*"dma2",*/apollo_dma_2_r, apollo_dma_2_w, 0xffffffff )
 		AM_RANGE(0x011000, 0x0110ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x011100, 0x0111ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x011200, 0x0112ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x011200, 0x0112ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 		AM_RANGE(0x011300, 0x0113ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x011600, 0x0116ff) AM_READWRITE8(master_req_register_r, master_req_register_w, 0xffffffff)
 
@@ -772,7 +760,7 @@ static ADDRESS_MAP_START(dn3000_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x009300, 0x0093ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x009400, 0x0094ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x009500, 0x0095ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x009600, 0x0096ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x009600, 0x0096ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 
 		AM_RANGE(0x05d800, 0x05dc07) AM_DEVREADWRITE8(APOLLO_SCREEN_TAG, apollo_graphics_15i, apollo_mcr_r, apollo_mcr_w, 0xffffffff)
 		AM_RANGE(0xfa0000, 0xfdffff) AM_DEVREADWRITE16(APOLLO_SCREEN_TAG, apollo_graphics_15i, apollo_mgm_r, apollo_mgm_w, 0xffffffff)
@@ -806,7 +794,7 @@ static ADDRESS_MAP_START(dsp3000_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x009300, 0x0093ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x009400, 0x0094ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x009500, 0x0095ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x009600, 0x0096ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x009600, 0x0096ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 
 		AM_RANGE(ATBUS_IO_BASE, ATBUS_IO_END) AM_READWRITE16(apollo_atbus_io_r, apollo_atbus_io_w, 0xffffffff)
 
@@ -835,7 +823,7 @@ static ADDRESS_MAP_START(dn5500_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x010d00, 0x010dff) AM_READWRITE8(/*"dma2",*/apollo_dma_2_r, apollo_dma_2_w, 0xffffffff )
 		AM_RANGE(0x011000, 0x0110ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x011100, 0x0111ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x011200, 0x0112ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x011200, 0x0112ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 		AM_RANGE(0x011300, 0x0113ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x011400, 0x0114ff) AM_READWRITE8(dn5500_memory_present_register_r, dn5500_memory_present_register_w, 0xffffffff )
 		AM_RANGE(0x011500, 0x0115ff) AM_READWRITE8(dn5500_11500_r, dn5500_11500_w, 0xffffffff )
@@ -882,7 +870,7 @@ static ADDRESS_MAP_START(dsp5500_map, AS_PROGRAM, 32, apollo_state )
 		AM_RANGE(0x010d00, 0x010dff) AM_READWRITE8(/*"dma2",*/apollo_dma_2_r, apollo_dma_2_w, 0xffffffff )
 		AM_RANGE(0x011000, 0x0110ff) AM_DEVREADWRITE8(APOLLO_PIC1_TAG, pic8259_device, read, write, 0xffffffff)
 		AM_RANGE(0x011100, 0x0111ff) AM_DEVREADWRITE8(APOLLO_PIC2_TAG, pic8259_device, read, write, 0xffffffff)
-		AM_RANGE(0x011200, 0x0112ff) AM_READWRITE16(apollo_node_id_r, apollo_node_id_w, 0xffffffff)
+		AM_RANGE(0x011200, 0x0112ff) AM_DEVREADWRITE16(APOLLO_NI_TAG, apollo_ni, read, write, 0xffffffff)
 		AM_RANGE(0x011300, 0x0113ff) AM_READWRITE16(latch_page_on_parity_error_register_r, latch_page_on_parity_error_register_w, 0xffffffff )
 		AM_RANGE(0x011400, 0x0114ff) AM_READWRITE8(dn5500_memory_present_register_r, dn5500_memory_present_register_w, 0xffffffff )
 		AM_RANGE(0x011500, 0x0115ff) AM_READWRITE8(dn5500_11500_r, dn5500_11500_w, 0xffffffff )
@@ -909,34 +897,21 @@ ADDRESS_MAP_END
 
 void apollo_state::machine_reset()
 {
-	//MLOG1(("machine_reset_dn3500"));
+	MLOG1(("machine_reset"));
 
 	MACHINE_RESET_CALL_MEMBER(apollo);
 
-	// we can't do this any more
-	#if 0
+#ifdef APOLLO_XXL
 	// set configuration
 	omti8621_device::set_verbose(apollo_config(APOLLO_CONF_DISK_TRACE));
 	threecom3c505_device::set_verbose(apollo_config(APOLLO_CONF_NET_TRACE));
 
 	if (apollo_config(APOLLO_CONF_NODE_ID))
 	{
-		UINT8 db[0x50];
-		UINT16 sector1 = apollo_is_dn5500() ? 4 : 1;
-
-		// check label of physical volume and get sector data of logical volume 1
-		// Note: sector data starts with 32 byte block header
-		if (omti8621_get_sector(machine().device(APOLLO_WDC_TAG), 0, db,    sizeof(db), 0) == sizeof(db) &&
-			memcmp (db+0x22, "APOLLO", 6) == 0 &&
-			omti8621_get_sector(machine().device(APOLLO_WDC_TAG), sector1, db,  sizeof(db), 0) == sizeof(db))
-		{
-			// set node_id from UID of logical volume 1 of logical unit 0
-			node_id = (((db[0x49] << 8) | db[0x4a]) << 8) | db[0x4b];
-
-			MLOG2(("machine_reset_dn3500: node ID is %06X (from disk)", node_id));
-		}
+		// set node ID from UID of logical volume 1 of logical unit 0
+		m_node_id->set_node_id_from_disk();
 	}
-	#endif
+#endif
 
 	m_maincpu->set_instruction_hook(read32_delegate(FUNC(apollo_state::apollo_instruction_hook),this));
 }
@@ -955,6 +930,9 @@ WRITE_LINE_MEMBER(apollo_state::apollo_reset_instr_callback)
 	{
 		machine().device(APOLLO_SCREEN_TAG)->reset();
 		machine().device(APOLLO_KBD_TAG )->reset();
+#ifdef APOLLO_XXL
+		machine().device(APOLLO_STDIO_TAG )->reset();
+#endif
 	}
 }
 
@@ -970,6 +948,10 @@ void apollo_state::machine_start(){
 	memset(messram->ptr(), 0x55, messram->bytes());
 
 	MACHINE_START_CALL_MEMBER(apollo);
+
+	// install nop handlers for unmapped ISA bus addresses
+	m_isa->install16_device(0, ATBUS_IO_END, 0, 0, read16_delegate(FUNC(apollo_state::apollo_atbus_unmap_io_r), this), write16_delegate(FUNC(apollo_state::apollo_atbus_unmap_io_w), this));
+	m_isa->install_memory(0, ATBUS_MEMORY_END, 0, 0, read8_delegate(FUNC(apollo_state::apollo_atbus_unmap_r), this), write8_delegate(FUNC(apollo_state::apollo_atbus_unmap_w), this));
 }
 
 /***************************************************************************
@@ -1078,6 +1060,11 @@ static MACHINE_CONFIG_START( dn3500, apollo_state )
 	MCFG_RAM_ADD("messram")
 	MCFG_RAM_DEFAULT_SIZE("8M")
 	MCFG_RAM_EXTRA_OPTIONS("4M,8M,16M,32M")
+
+#ifdef APOLLO_XXL
+	MCFG_DEVICE_ADD(APOLLO_STDIO_TAG, APOLLO_STDIO, 0)
+	MCFG_APOLLO_STDIO_TX_CALLBACK(DEVWRITELINE(APOLLO_SIO_TAG, apollo_sio, rx_b_w))
+#endif
 MACHINE_CONFIG_END
 
 static MACHINE_CONFIG_START( dsp3500, apollo_state )
@@ -1220,8 +1207,6 @@ ROM_START( dn3500 )
 	// Note: this duplicates boot rom md7c-rev-8.00-1989-08-16-17-23-52.bin
 	ROM_SYSTEM_BIOS( 0, "md7c-rev-8.00", "MD7C REV 8.00, 1989/08/16.17:23:52" )
 	ROMX_LOAD( "3500_boot_12191_7.bin", 0x00000, 0x10000, CRC(3132067d) SHA1(36f3c83d9f2df42f2537b09ca2f051a8c9dfbfc2) , ROM_BIOS(1) )
-
-	ROM_LOAD_OPTIONAL( "3000_3c505_010728-00.bin", 0x80000, 0x02000, CRC(69b77ec6) SHA1(7ac36cc6fc90b90ddfc56c45303b514cbe18ae58) )
 ROM_END
 
 ROM_START( dn5500 )
@@ -1230,8 +1215,6 @@ ROM_START( dn5500 )
 
 	ROM_SYSTEM_BIOS( 0, "md7c-rev-8.00", "MD7C REV 8.00, 1989/08/16.17:23:52" )
 	ROMX_LOAD( "5500_boot_a1631-80046_1-30-92.bin", 0x00000, 0x10000, CRC(7b9ed610) SHA1(7315a884ec4551c44433c6079cc06509223cb02b) , ROM_BIOS(1) )
-
-	ROM_LOAD_OPTIONAL( "3000_3c505_010728-00.bin", 0x80000, 0x02000, CRC(69b77ec6) SHA1(7ac36cc6fc90b90ddfc56c45303b514cbe18ae58) )
 ROM_END
 
 ROM_START( dn3000)
@@ -1239,8 +1222,6 @@ ROM_START( dn3000)
 
 	ROM_SYSTEM_BIOS( 0, "md8-rev-7.0", "MD8 REV 7.0, 1988/08/16.15:14:39" )
 	ROMX_LOAD( "3000_boot_8475_7.bin",  0x00000, 0x08000, CRC(0fe2d471) SHA1(6c383d2266719a3d069b7bf015f6945179395e7a), ROM_BIOS(1) )
-
-	ROM_LOAD_OPTIONAL( "3000_3c505_010728-00.bin", 0x80000, 0x02000, CRC(69b77ec6) SHA1(7ac36cc6fc90b90ddfc56c45303b514cbe18ae58) )
 ROM_END
 
 #define rom_dsp3500    rom_dn3500
diff --git a/src/mame/includes/apollo.h b/src/mame/includes/apollo.h
index 41b0f04e6ff..5029cdc340e 100644
--- a/src/mame/includes/apollo.h
+++ b/src/mame/includes/apollo.h
@@ -46,12 +46,16 @@
 #define MLOG(x)  { logerror ("%s: ", apollo_cpu_context(machine().device(MAINCPU))); LOG(x) }
 #define MLOG1(x) { if (VERBOSE > 0) MLOG(x) }
 #define MLOG2(x) { if (VERBOSE > 1) MLOG(x) }
-#define SLOG(x)  { logerror ("%s: ", apollo_cpu_context(&space.device())); LOG(x) }
+#define SLOG(x)  { logerror ("%s: ", apollo_cpu_context(m_maincpu)); LOG(x) }
 #define SLOG1(x) { if (VERBOSE > 0) SLOG(x) }
 #define SLOG2(x) { if (VERBOSE > 1) SLOG(x) }
 
 #define  MAINCPU "maincpu"
 
+// Enabling this is >NOT< supported by MESSdev
+// Do *not* report any issues on Mametesters if this is enabled!
+// #define APOLLO_XXL
+
 /*----------- machine/apollo_dbg.c -----------*/
 
 int apollo_debug_instruction_hook(m68000_base_device *device, offs_t curpc);
@@ -70,6 +74,9 @@ void apollo_check_log();
 // return 1 if node is DN3000 or DSP3000, 0 otherwise
 int apollo_is_dn3000(void);
 
+// return 1 if node is DN5500 or DSP5500, 0 otherwise
+int apollo_is_dn5500(void);
+
 // return 1 if node is DSP3000 or DSP3500, 0 otherwise
 int apollo_is_dsp3x00(void);
 
@@ -98,10 +105,12 @@ void apollo_set_cache_status_register(UINT8 mask, UINT8 data);
 #define APOLLO_SIO_TAG  "sio"
 #define APOLLO_SIO2_TAG "sio2"
 #define APOLLO_ETH_TAG  "3c505"
+#define APOLLO_NI_TAG  "node_id"
 #define APOLLO_ISA_TAG "isabus"
 
 // forward declaration
 class apollo_sio;
+class apollo_ni;
 
 class apollo_state : public driver_device
 {
@@ -118,6 +127,7 @@ public:
 			m_sio(*this, APOLLO_SIO_TAG),
 			m_sio2(*this, APOLLO_SIO2_TAG),
 			m_rtc(*this, APOLLO_RTC_TAG),
+			m_node_id(*this, APOLLO_NI_TAG),
 			m_isa(*this, APOLLO_ISA_TAG)
 			{ }
 
@@ -132,6 +142,7 @@ public:
 	required_device<apollo_sio> m_sio;
 	optional_device<apollo_sio> m_sio2;
 	required_device<mc146818_device> m_rtc;
+	required_device<apollo_ni> m_node_id;
 	required_device<isa16_device> m_isa;
 
 	DECLARE_WRITE16_MEMBER(apollo_csr_status_register_w);
@@ -173,6 +184,10 @@ public:
 	DECLARE_WRITE16_MEMBER(apollo_atbus_io_w);
 	DECLARE_READ16_MEMBER(apollo_atbus_memory_r);
 	DECLARE_WRITE16_MEMBER(apollo_atbus_memory_w);
+	DECLARE_READ16_MEMBER(apollo_atbus_unmap_io_r);
+	DECLARE_WRITE16_MEMBER(apollo_atbus_unmap_io_w);
+	DECLARE_READ8_MEMBER(apollo_atbus_unmap_r);
+	DECLARE_WRITE8_MEMBER(apollo_atbus_unmap_w);
 	DECLARE_WRITE8_MEMBER(dn5500_memory_present_register_w);
 	DECLARE_READ8_MEMBER(dn5500_memory_present_register_r);
 	DECLARE_WRITE8_MEMBER(dn5500_11500_w);
@@ -335,6 +350,55 @@ private:
 
 extern const device_type APOLLO_SIO;
 
+/*----------- machine/apollo_ni.c -----------*/
+
+#define MCFG_APOLLO_NI_ADD(_tag, _xtal) \
+	MCFG_DEVICE_ADD(_tag, APOLLO_NI, _xtal)
+
+/*** Apollo Node ID device ***/
+
+class apollo_ni: public device_t, public device_image_interface
+{
+public:
+	// construction/destruction
+	apollo_ni(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
+	virtual ~apollo_ni();
+
+	virtual iodevice_t image_type() const { return IO_ROM; }
+
+	virtual bool is_readable()  const { return 1; }
+	virtual bool is_writeable() const { return 1; }
+	virtual bool is_creatable() const { return 1; }
+	virtual bool must_be_loaded() const { return 0; }
+	virtual bool is_reset_on_load() const { return 0; }
+	virtual const char *image_interface() const { return NULL; }
+	virtual const char *file_extensions() const { return "ani,bin"; }
+	virtual const option_guide *create_option_guide() const { return NULL; }
+
+	DECLARE_WRITE16_MEMBER(write);
+	DECLARE_READ16_MEMBER(read);
+
+	// image-level overrides
+	virtual bool call_load();
+	virtual bool call_create(int format_type, option_resolution *format_options);
+	virtual void call_unload();
+
+	void set_node_id_from_disk();
+
+protected:
+	// device-level overrides
+	virtual void device_config_complete() ;
+	virtual void device_start();
+	virtual void device_reset();
+
+private:
+	void set_node_id(UINT32 node_id);
+	UINT32 m_node_id;
+};
+
+// device type definition
+extern const device_type APOLLO_NI;
+
 /*----------- video/apollo.c -----------*/
 
 #define APOLLO_SCREEN_TAG "apollo_screen"
@@ -599,4 +663,62 @@ extern const device_type APOLLO_MONO19I;
 
 MACHINE_CONFIG_EXTERN( apollo_mono19i );
 
+#ifdef APOLLO_XXL
+
+/*----------- machine/apollo_stdio.c -----------*/
+
+//**************************************************************************
+//  DEVICE CONFIGURATION MACROS
+//**************************************************************************
+
+#define MCFG_APOLLO_STDIO_TX_CALLBACK(_cb) \
+	devcb = &apollo_stdio_device::set_tx_cb(*device, DEVCB_##_cb);
+
+//**************************************************************************
+//  TYPE DEFINITIONS
+//**************************************************************************
+
+// ======================> apollo_stdio_device
+
+class apollo_stdio_device: public device_t, public device_serial_interface
+{
+public:
+	// construction/destruction
+	apollo_stdio_device(const machine_config &mconfig, const char *tag,
+			device_t *owner, UINT32 clock);
+
+	template<class _Object> static devcb_base &set_tx_cb(device_t &device, _Object object)
+	{
+		return downcast<apollo_stdio_device &> (device).m_tx_w.set_callback(object);
+	}
+
+	devcb_write_line m_tx_w;
+
+private:
+	// device-level overrides
+	virtual void device_start();
+	virtual void device_reset();
+	virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr);
+
+	// serial overrides
+	virtual void rcv_complete(); // Rx completed receiving byte
+	virtual void tra_complete(); // Tx completed sending byte
+	virtual void tra_callback(); // Tx send bit
+
+	TIMER_CALLBACK_MEMBER( poll_timer );
+	void xmit_char(UINT8 data);
+
+	static const int XMIT_RING_SIZE = 64;
+
+	UINT8 m_xmitring[XMIT_RING_SIZE];
+	int m_xmit_read, m_xmit_write;
+	bool m_tx_busy;
+
+	emu_timer* m_poll_timer;
+};
+
+// device type definition
+extern const device_type APOLLO_STDIO;
+#endif /* APOLLO_XXL */
+
 #endif /* APOLLO_H_ */
diff --git a/src/mame/machine/apollo.c b/src/mame/machine/apollo.c
index 568a9c08fc8..5ab3b5dd4fe 100644
--- a/src/mame/machine/apollo.c
+++ b/src/mame/machine/apollo.c
@@ -95,11 +95,11 @@ INPUT_PORTS_START( apollo_config )
 		PORT_CONFNAME(APOLLO_CONF_25_YEARS_AGO, APOLLO_CONF_25_YEARS_AGO, "25 Years Ago ...")
 		PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
 		PORT_CONFSETTING(APOLLO_CONF_25_YEARS_AGO, DEF_STR ( On ) )
-
-//      PORT_CONFNAME(APOLLO_CONF_NODE_ID, APOLLO_CONF_NODE_ID, "Node ID from Disk")
-//      PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
-//      PORT_CONFSETTING(APOLLO_CONF_NODE_ID, DEF_STR ( On ) )
-
+#ifdef APOLLO_XXL
+		PORT_CONFNAME(APOLLO_CONF_NODE_ID, APOLLO_CONF_NODE_ID, "Node ID from Disk")
+		PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
+		PORT_CONFSETTING(APOLLO_CONF_NODE_ID, DEF_STR ( On ) )
+#endif
 //      PORT_CONFNAME(APOLLO_CONF_IDLE_SLEEP, 0x00, "Idle Sleep")
 //      PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
 //      PORT_CONFSETTING(APOLLO_CONF_IDLE_SLEEP, DEF_STR ( On ) )
@@ -111,15 +111,15 @@ INPUT_PORTS_START( apollo_config )
 		PORT_CONFNAME(APOLLO_CONF_FPU_TRACE, 0x00, "FPU Trace")
 		PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
 		PORT_CONFSETTING(APOLLO_CONF_FPU_TRACE, DEF_STR ( On ) )
+#ifdef APOLLO_XXL
+		PORT_CONFNAME(APOLLO_CONF_DISK_TRACE, 0x00, "Disk Trace")
+		PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
+		PORT_CONFSETTING(APOLLO_CONF_DISK_TRACE, DEF_STR ( On ) )
 
-//      PORT_CONFNAME(APOLLO_CONF_DISK_TRACE, 0x00, "Disk Trace")
-//      PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
-//      PORT_CONFSETTING(APOLLO_CONF_DISK_TRACE, DEF_STR ( On ) )
-
-//      PORT_CONFNAME(APOLLO_CONF_NET_TRACE, 0x00, "Network Trace")
-//      PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
-//      PORT_CONFSETTING(APOLLO_CONF_NET_TRACE, DEF_STR ( On ) )
-
+		PORT_CONFNAME(APOLLO_CONF_NET_TRACE, 0x00, "Network Trace")
+		PORT_CONFSETTING(0x00, DEF_STR ( Off ) )
+		PORT_CONFSETTING(APOLLO_CONF_NET_TRACE, DEF_STR ( On ) )
+#endif
 INPUT_PORTS_END
 
 class apollo_config_device : public device_t
@@ -856,6 +856,216 @@ WRITE_LINE_MEMBER(apollo_state::sio2_irq_handler)
 	apollo_pic_set_irq_line(APOLLO_IRQ_SIO2, state);
 }
 
+//##########################################################################
+// machine/apollo_ni.c - APOLLO DS3500 node ID
+//##########################################################################
+
+#undef VERBOSE
+#define VERBOSE 0
+
+#define DEFAULT_NODE_ID 0x12345
+
+/***************************************************************************
+ IMPLEMENTATION
+ ***************************************************************************/
+
+/*** Apollo Node ID device ***/
+
+// device type definition
+const device_type APOLLO_NI = &device_creator<apollo_ni> ;
+
+//-------------------------------------------------
+//  apollo_ni - constructor
+//-------------------------------------------------
+
+apollo_ni::apollo_ni(const machine_config &mconfig, const char *tag,
+		device_t *owner, UINT32 clock) :
+	device_t(mconfig, APOLLO_NI, "Node ID", tag, owner, clock, "node ID",
+			__FILE__), device_image_interface(mconfig, *this)
+{
+}
+
+//-------------------------------------------------
+//  apollo_ni - destructor
+//-------------------------------------------------
+
+apollo_ni::~apollo_ni()
+{
+}
+
+void apollo_ni::device_config_complete()
+{
+	update_names(APOLLO_NI, "node_id", "ni");
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void apollo_ni::device_start()
+{
+	CLOG1(("apollo_ni::device_start"));
+	set_node_id(DEFAULT_NODE_ID);
+}
+
+//-------------------------------------------------
+//  device_reset - device-specific reset
+//-------------------------------------------------
+
+void apollo_ni::device_reset()
+{
+	CLOG1(("apollo_ni::device_reset"));
+}
+
+//-------------------------------------------------
+//  set node ID
+//-------------------------------------------------
+
+void apollo_ni::set_node_id(UINT32 node_id)
+{
+	m_node_id = node_id;
+	CLOG1(("apollo_ni::set_node_id: node ID is %x", node_id));
+}
+
+//-------------------------------------------------
+//  read/write
+//-------------------------------------------------
+
+WRITE16_MEMBER(apollo_ni::write)
+{
+	CLOG1(("Error: writing node id ROM at offset %02x = %04x & %04x", offset, data, mem_mask));
+}
+
+READ16_MEMBER(apollo_ni::read)
+{
+	UINT16 data = 0;
+	switch (offset & 0x0f)
+	{
+	case 1: // msb
+		data = (m_node_id >> 16) & 0xff;
+		break;
+	case 2:
+		data = (m_node_id >> 8) & 0xff;
+		break;
+	case 3: // lsb
+		data = m_node_id & 0xff;
+		break;
+	case 15: // checksum
+		data = ((m_node_id >> 16) + (m_node_id >> 8) + m_node_id) & 0xff;
+		break;
+	default:
+		data = 0;
+		break;
+	}
+	data <<= 8;
+	CLOG2(("reading node id ROM at offset %02x = %04x & %04x", offset, data, mem_mask));
+	return data;
+}
+
+/*-------------------------------------------------
+ DEVICE_IMAGE_LOAD( rom )
+ -------------------------------------------------*/
+bool apollo_ni::call_load()
+{
+	CLOG1(("apollo_ni::call_load: %s", filename()));
+
+	UINT64 size = length();
+	 if (size != 32)
+	{
+		CLOG(("apollo_ni::call_load: %s has unexpected file size %lld", filename(), size));
+	}
+	else
+	{
+		UINT8 data[32];
+		fread(data, sizeof(data));
+
+		UINT8 checksum = data[2] + data[4] + data[6];
+		if (checksum != data[30])
+		{
+			CLOG(("apollo_ni::call_load: checksum is %02x - should be %02x", checksum, data[30]));
+		}
+		else
+		{
+			m_node_id = (((data[2] << 8) | data[4]) << 8) | (data[6]);
+			CLOG1(("apollo_ni::call_load: node ID is %x", m_node_id));
+			return IMAGE_INIT_PASS;
+		}
+	}
+	return IMAGE_INIT_FAIL;
+}
+
+/*-------------------------------------------------
+ DEVICE_IMAGE_CREATE( rom )
+ -------------------------------------------------*/
+
+bool apollo_ni::call_create(int format_type, option_resolution *format_options)
+{
+	CLOG1(("apollo_ni::call_create:"));
+
+	if (length() > 0)
+	{
+		CLOG(("apollo_ni::call_create: %s already exists", filename()));
+	}
+	else
+	{
+		UINT32 node_id = 0;
+		sscanf(basename_noext(), "%x", &node_id);
+		if (node_id == 0 || node_id > 0xfffff)
+		{
+			CLOG(("apollo_ni::call_create: filename %s is no valid node ID", basename()));
+		}
+		else
+		{
+			UINT8 data[32];
+			memset(data, 0, sizeof(data));
+			data[2] = node_id >> 16;
+			data[4] = node_id >> 8;
+			data[6] = node_id;
+			data[30] = data[2] + data[4] + data[6];
+			fwrite(data, sizeof(data));
+			CLOG(("apollo_ni::call_create: created %s with node ID %x", filename(), node_id));
+			set_node_id(node_id);
+			return IMAGE_INIT_PASS;
+		}
+	}
+	return IMAGE_INIT_FAIL;
+}
+
+/*-------------------------------------------------
+ DEVICE_IMAGE_UNLOAD( rom )
+ -------------------------------------------------*/
+void apollo_ni::call_unload()
+{
+	CLOG1(("apollo_ni::call_unload:"));
+}
+
+//-------------------------------------------------
+//  set node ID from disk
+//-------------------------------------------------
+
+void apollo_ni::set_node_id_from_disk()
+{
+#ifdef APOLLO_XXL
+	// set node ID from UID of logical volume 1 of logical unit 0
+	UINT8 db[0x50];
+
+	// check label of physical volume and get sector data of logical volume 1
+	// Note: sector data starts with 32 byte block header
+	if (omti8621_device::get_sector(0, db, sizeof(db), 0) == sizeof(db)
+			&& memcmp(db + 0x22, "APOLLO", 6) == 0)
+	{
+		UINT16 sector1 = apollo_is_dn5500() ? 4 : 1;
+
+		if (omti8621_device::get_sector(sector1, db, sizeof(db), 0) == sizeof(db))
+		{
+			// set node_id from UID of logical volume 1 of logical unit 0
+			m_node_id = (((db[0x49] << 8) | db[0x4a]) << 8) | db[0x4b];
+			CLOG1(("apollo_ni::set_node_id_from_disk: node ID is %x", m_node_id));
+		}
+	}
+#endif
+}
+
 //##########################################################################
 // machine/apollo.c - APOLLO DS3500 CPU Board
 //##########################################################################
@@ -916,6 +1126,11 @@ MACHINE_CONFIG_FRAGMENT( common )
 
 	MCFG_MC146818_ADD( APOLLO_RTC_TAG, XTAL_32_768kHz )
 	MCFG_MC146818_UTC( true )
+	MCFG_MC146818_BINARY( false )
+	MCFG_MC146818_24_12( false )
+	MCFG_MC146818_EPOCH( 0 )
+
+	MCFG_APOLLO_NI_ADD( APOLLO_NI_TAG, 0 )
 
 	MCFG_APOLLO_SIO_ADD( APOLLO_SIO2_TAG, XTAL_3_6864MHz )
 	MCFG_APOLLO_SIO_IRQ_CALLBACK(WRITELINE(apollo_state, sio2_irq_handler))
@@ -959,6 +1174,10 @@ MACHINE_CONFIG_FRAGMENT( apollo )
 	MCFG_APOLLO_SIO_IRQ_CALLBACK(WRITELINE(apollo_state, sio_irq_handler))
 	MCFG_APOLLO_SIO_OUTPORT_CALLBACK(WRITE8(apollo_state, sio_output))
 	MCFG_APOLLO_SIO_A_TX_CALLBACK(DEVWRITELINE(APOLLO_KBD_TAG, apollo_kbd_device, rx_w))
+
+#ifdef APOLLO_XXL
+	MCFG_APOLLO_SIO_B_TX_CALLBACK(DEVWRITELINE(APOLLO_STDIO_TAG, apollo_stdio_device, rx_w))
+#endif
 MACHINE_CONFIG_END
 
 static DEVICE_INPUT_DEFAULTS_START( apollo_terminal )
@@ -1015,20 +1234,20 @@ MACHINE_RESET_MEMBER(apollo_state,apollo)
 	apollo_csr_set_servicemode(apollo_config(APOLLO_CONF_SERVICE_MODE));
 
 	// change year according to configuration settings
-	if (year < 20 && apollo_config(APOLLO_CONF_20_YEARS_AGO))
-	{
-		year+=80;
-		apollo_rtc_w(space, 9, year);
-	}
-	else if (year < 25 && apollo_config(APOLLO_CONF_25_YEARS_AGO))
+	if (year < 25 && apollo_config(APOLLO_CONF_25_YEARS_AGO))
 	{
 		year += 75;
 		apollo_rtc_w(space, 9, year);
 	}
+	else if (year < 20 && apollo_config(APOLLO_CONF_20_YEARS_AGO))
+	{
+		year += 80;
+		apollo_rtc_w(space, 9, year);
+	}
 	else if (year >= 80 && !apollo_config(APOLLO_CONF_20_YEARS_AGO)
 			&& !apollo_config(APOLLO_CONF_25_YEARS_AGO))
 	{
-		year -=80;
+		year -= 80;
 		apollo_rtc_w(space, 9, year);
 	}
 
@@ -1040,3 +1259,154 @@ MACHINE_RESET_MEMBER(apollo_state,apollo)
 		m_dn3000_timer->adjust(attotime::from_hz(2), 0, attotime::from_hz(2));
 	}
 }
+
+#ifdef APOLLO_XXL
+
+//##########################################################################
+// machine/apollo_stdio.c - stdio terminal for mess
+//##########################################################################
+
+#undef VERBOSE
+#define VERBOSE 0
+
+#if defined(__linux__)
+#include <fcntl.h>
+#include <unistd.h>
+#endif
+
+/***************************************************************************
+ IMPLEMENTATION
+ ***************************************************************************/
+
+// device type definition
+const device_type APOLLO_STDIO = &device_creator<apollo_stdio_device> ;
+
+//-------------------------------------------------
+// apollo_stdio_device - constructor
+//-------------------------------------------------
+
+apollo_stdio_device::apollo_stdio_device(const machine_config &mconfig,
+		const char *tag, device_t *owner, UINT32 clock) :
+	device_t(mconfig, APOLLO_STDIO, "Apollo STDIO", tag, owner, clock,
+			"apollo_stdio", __FILE__), device_serial_interface(mconfig, *this),
+			m_tx_w(*this)
+{
+}
+
+//-------------------------------------------------
+//  device_start - device-specific startup
+//-------------------------------------------------
+
+void apollo_stdio_device::device_start()
+{
+	CLOG1(("device_start"));
+
+	m_tx_w.resolve_safe();
+
+	m_poll_timer = machine().scheduler().timer_alloc(timer_expired_delegate(
+			FUNC(apollo_stdio_device::poll_timer), this));
+}
+
+//-------------------------------------------------
+//  device_reset - device-specific reset
+//-------------------------------------------------
+
+void apollo_stdio_device::device_reset()
+{
+	CLOG1(("device_reset"));
+
+	// comms is at 8N1, 9600 baud
+	set_data_frame(1, 8, PARITY_NONE, STOP_BITS_1);
+	set_rcv_rate(9600);
+	set_tra_rate(9600);
+
+	m_tx_busy = false;
+	m_xmit_read = m_xmit_write = 0;
+
+#if defined(__linux__)
+	// FIXME: unavailable in mingw
+	// set stdin to nonblocking to allow polling
+	fcntl(STDIN_FILENO, F_SETFL, fcntl(STDIN_FILENO, F_GETFL) | O_NONBLOCK);
+#endif
+
+	// start timer
+	m_poll_timer->adjust(attotime::zero, 0, attotime::from_msec(1)); // every 1ms
+}
+
+void apollo_stdio_device::device_timer(emu_timer &timer, device_timer_id id,
+		int param, void *ptr)
+{
+	device_serial_interface::device_timer(timer, id, param, ptr);
+}
+
+void apollo_stdio_device::rcv_complete() // Rx completed receiving byte
+{
+	receive_register_extract();
+	UINT8 data = get_received_char();
+
+	// output data to stdout (FIXME: '\r' may confuse ceterm)
+	if (data != '\r')
+	{
+		::putchar(data);
+		::fflush(stdout);
+	}
+	CLOG1(("rcv_complete %02x - %c", data, data));
+}
+
+void apollo_stdio_device::tra_complete() // Tx completed sending byte
+{
+	// is there more waiting to send?
+	if (m_xmit_read != m_xmit_write)
+	{
+		transmit_register_setup(m_xmitring[m_xmit_read++]);
+		if (m_xmit_read >= XMIT_RING_SIZE)
+		{
+			m_xmit_read = 0;
+		}
+	}
+	else
+	{
+		m_tx_busy = false;
+	}
+}
+
+void apollo_stdio_device::tra_callback() // Tx send bit
+{
+	int bit = transmit_register_get_data_bit();
+	m_tx_w(bit);
+
+	CLOG2(("tra_callback %02x", bit));
+}
+
+TIMER_CALLBACK_MEMBER(apollo_stdio_device::poll_timer)
+{
+#if defined(__linux__)
+	UINT8 data;
+	while (::read(STDIN_FILENO, &data, 1) == 1)
+	{
+		xmit_char(data == '\n' ? '\r' : data);
+	}
+#endif
+}
+
+void apollo_stdio_device::xmit_char(UINT8 data)
+{
+	CLOG1(("xmit_char %02x - %c", data, data));
+
+	// if tx is busy it'll pick this up automatically when it completes
+	if (!m_tx_busy)
+	{
+		m_tx_busy = true;
+		transmit_register_setup(data);
+	}
+	else
+	{
+		// tx is busy, it'll pick this up next time
+		m_xmitring[m_xmit_write++] = data;
+		if (m_xmit_write >= XMIT_RING_SIZE)
+		{
+			m_xmit_write = 0;
+		}
+	}
+}
+#endif
diff --git a/src/osd/osdnet.c b/src/osd/osdnet.c
index 023eecbab6e..9fd92311ea7 100644
--- a/src/osd/osdnet.c
+++ b/src/osd/osdnet.c
@@ -49,7 +49,8 @@ osd_netdev::osd_netdev(class device_network_interface *ifdev, int rate)
 osd_netdev::~osd_netdev()
 {
 	m_stop = true;
-	m_timer->reset();
+// nasty hack to prevent Segmentation fault on emulation stop
+//	m_timer->reset();
 }
 
 int osd_netdev::send(UINT8 *buf, int len)