Guides:MAME - Linked Mode
Linked Mode Arcade Machine
Linking Virtua Racing, this machine uses serial based comms
MAME supports the following cli options for serial based comms
-comm_localhost -comm_localport -comm_remotehost -comm_remoteport
To successfully link two+ Virtua Racing instances you will need two separate nvmram directories because you will need to set the machines as master/slave devices as applicable
- The first machine (Car 1) will be the Master in all cases
- Each additional machine (Car) will
* be in slave mode * need a port open to listen on * be on the same network with an ip address
Setup (2 machines)
- Create two nvram directories to store the machine configs
- Get the IP address of the each machine
- Assign each machine a port with their IP address, just do this on piece of paper for now
One the first machine (car 1 / master) start mame
mame vr -nvram_directory <path to nvram> -localhost <machine1 ip> -comm_localport <machine1 port> -remotehost <machine2 ip> -remoteport <machine2 port>
On the second machine (car 2 / slave) start mame
mame vr -nvram_directory <path to nvram> -localhost <machine2 ip> -comm_localport <machine2 port> -remotehost <machine1 ip> -remoteport <machine1 port>
When the games start for the first time set their mode
- Press F2 to enter test mode, navigate
- Navigate to GAME SYSTEM
- LINK ID -> Master (machine 1) or Slave (machine 2+)
- Back out of the menu and when prompted save your settings
- Exit test mode
The two machines should find each other and the game will start
Troubleshooting
Some basic troubleshooting techniques when trying to setup linked mode
In all cases below the mame command line from machine1 looked like this, and all traffic (to date) has been TCP
mame vr -localhost 0.0.0.0 -comm_localport 15111 -remotehost 10.0.100.102 -remoteport 15112
Is MAME listening?
Check to see if MAME is actually listening locally on the ip/port you supplied to localhost and localport, do this on all machines
# ss -lnp | grep mame tcp LISTEN 0 1 0.0.0.0:15111 0.0.0.0:*
Is the MAME port open
Use telnet to try and connect to the port from the remote host
$ telnet 10.0.100.102 15112 Trying 10.0.100.102... Connected to 10.0.100.102. Escape character is '^]'.
This shows the connection was successful ruling out firewall issues on the remote end
Is there traffic flow out of MAME
Run tcpdump to monitor the TCP traffic from one machine to the other, this is useful to see if there is _any_ flow out of the machine, some machines may not yet have active functionality for linking regardless of if the machine runs or not.
# tcpdump -n host 10.0.100.102 and port 15112