The biggest difference to Erlang is VxWork's inability to isolate task faults or runaway high priority process. (Tasks are analogous to Processes in Erlang). VxWorks 6.0 supports isolation to some degree, but it was released in '04, after the design work on the rover started. Without total isolation, a lot of the supervisor benefits of VxWorks goes away.
Erlang could use a bit more isolation as well. For example limiting the mailbox size and limiting the memory available to a single process.
Memory limits would be great to give you some ease of mind when reusing libraries for processing input. For example processing XML, even using SAX parser, still leaves you open for attacks like huge tag values or just something more real world, huge href="data:" attributes. Obviously the right way is to have a limit in the parser (which xmerl doesn’t have, unfortunately), in this case, but it’d be nice to have some safety net from the VM as well.
Hm.. What do you mean by isolating task faults? I think a lot of that depends on the underlying hardware, right (e.g., if the board has an MMU)? I know you can insert a taskSwitchHook (I think it's called) that could be able to detect and kill runaway high-priority processes.
Edit: in response to the reply, I suppose I should have mean tasks instead of "processes" (which in VxWorks would be the RTP)
VxWorks has no processes[1]. It has tasks. Basically, you write kernel code, there's no user mode.
[1] As someone mentioned, VxVorks 6 did introduce processes and "usermode", called RTP. As with most features of VxWorks, you compile that into your image if you want the feature. But there's a lot of inertia, and much of the VxWorks stuff I see doesn't use RTP yet.
