AFAICT，它不支持同时运行多个实例。

AFAICT, it does not support multiple instances running at the same time.

我尝试了两种方法，但都失败了。

I tried two methods, but both failed.

$ open -n /Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone\ Simulator.app
LSOpenURLsWithRole() failed with error -10829 for the file /Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone Simulator.app.

使用别名（http://forums.creativecow.net/thread/71/860074）带来一个dailog框说一次只能运行一个iOS模拟器。请退出iOS模拟器再试一次。

Using an alias (http://forums.creativecow.net/thread/71/860074) brings up a dailog box saying "Only one iOS Simulator can run at a time. Please quit iOS Simulator and try again."