Comment 40 for bug 93546

Randy,

There's no guarantees under Windows whether you get a new process or same the
process. It's up to the application developer. If they don't do anything
special, you will get multiple processes. What changed with Win95 (well, Win32)
was that the HANDLE to the previous instance was no longer passed to WinMain, so
application developers had to start using named mutexes, or named pipes or
FindWindow if they wanted to have one process only. Try launching Word multiple
times, you will not succeed (Office XP at least).

Explorer/Internet Explorer is an interesting case. It has an option in its
preferences dialog to run multiple processes. This is the first thing that I
enable when I sit down at fresh installation/new user environment. The stupid
default of having it disabled will mean the shell dies whenever a crash occurs
in another window. Anyway, IE allows multiple processes, which is vital IMHO
considering how often I make it crash. Some of the shared data is accessed
through separate singleton processes, like the Protected Storage service that
originally came with IE4.

I would really like to see the ability to launch Mozilla in multiple processes.
 This will make it more reliable and more useful. Concurrency of the shared
data is going to be a problem though. Do we have something in the toolkit that
allows interprocess communication on all the Mozilla platforms? E.g. a CORBA
based profile/configuration service/daemon would be very useful.