Environment Variables


There are a couple of environment variables that can be set to alter the default behavior of the ACCESS Linux Platform Simulator:
UML_TARGET, UML_ROOT
By default the Simulator boots the Scratchbox target named "alp-simulator" unless the UML_TARGET or UML_ROOT variables are defined. Use UML_TARGET to specify the Scratchbox target to boot. Use UML_ROOT to specify a path to the UML root filesystem. For example:
export UML_TARGET=my-simulator
or
export UML_ROOT=/path/to/uml/rootfs
UML_DIR
This variable allows you to specify an alternate path to the UML binary. By default, the command alp-sim runs /opt/alp-dev/lib/alp-simulator.
UML_MEM
Specifies the amount of physical memory the Simulator is launched with. By default, it is launched with 64 MB of physical memory. To change it, for instance to 256 MB:
export UML_MEM=256M
UML_NET_IP
When the --net option is used the bridge is configured using DHCP unless the environment variable UML_NET_IP is set, in which case the bridge is statically configured using the value of UML_NET_IP.
UML_NET_IFACE
When the --net option is used, during configuration of the bridge if the environment variable UML_NET_IFACE is set its value is taken as the bridge endpoint on a LAN (i.e., if you have several Ethernet cards).
DISPLAY
The DISPLAY variable specifies the X display server. For example:
DISPLAY=192.168.108.123:0.0 alp-simulator
UML_XSCREEN
The screen number to be used by the UML internal Xephyr is :0. An alternate may be provided by defining UML_XSCREEN, like this:
UML_XSCREEN=:1 alp-simulator
PALMSOURCE_COMPORT_VP
By default, the UML environment expects to contact the Virtual Phone program at 192.168.3.100. An alternate address can be provided by defining PALMSOURCE_COMPORT_VP:
PALMSOURCE_COMPORT_VP=192.168.108.123
PALMTRACE_TARGET
If the trace facility is configured to output to "tcp:", with no host specified, the trace facility looks to the PALMTRACE_TARGET variable for the host and optional port number of the trace target (Palm OS Reporter).

Networking

The first time you run the Simulator engine with the --nat option, it is configured so that subsequent runs of the Simulator should support networking without you having to again specify the --nat option.

Use the --nat option for:

  • Virtual Phone (running on a different machine)
  • Palm Reporter
  • Cygwin/X
  • gaining access to your local network or the Internet from inside UML without using the Connection Manager (or applications that use it).

The --nat option turns your Ubuntu computer into a gateway for your UML. DNS servers are copied inside the UML rootfs.

Use the --net option for:

  • gaining access to your local network or the Internet from inside UML through the Connection Manager (or applications that use it).

The --net (as opposed to --nat) option enables an Ethernet connection with the Connection Manager (or applications that use it). This option has the following effects:

  • Sets your Ethernet connection down on your Ubuntu computer.
  • Creates a bridge between your Ethernet card and a virtual interface.
  • Configures the bridge. This is done using DHCP unless the environment variable UML_NET_IP is set, in which case the bridge is statically configured using the value of UML_NET_IP. If the environment variable UML_NET_IFACE is set, its value is taken as the bridge endpoint on a LAN (i.e. if you have several Ethernet cards).
  • Launches a virtual switch (which is connected to the virtual connection) in a new xterm. The window appears when you start the Simulator.
  • Starts UML with an additional Ethernet interface (eth1) which is connected to the virtual switch. The --net-keep option skips this step but performs the others, allowing for faster starts the next time you start the Simulator with either --net or --net-keep.

When you halt UML, the virtual switch is killed, the bridge is destroyed, and your Ethernet is restored.

The --net option automatically includes --nat. To get the --net option without the effects of --nat, use the --net-nonat option instead.

NOTE: Don't worry about the huge size of the traces of the virtual switch inside the xterm: this is a side effect of the bridge configuration. After several hours, the virtual switch can slow down the performances of your Ubuntu computer. In this case, halt your UML and restart it.

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