There is also the possibility of using external power for the bus, so you can power more devices, but you'll need to not put too much current through any of the devices.
The extreme would be putting an ADB hub with external power every 5 devices :)
@LaPorta - it's not used much at all. You'd never use it unless you were doing calligraphy or other heavily stylised text, or writing a certain type of fiction. The only usage I remember off the top of my head is dæmon, which isn't how normal people spell it. The internet tells me it is called...
So just checking things.
The "MIDI Manager" software has several parts.
MIDI Manager - this can go in the System Folder or Extensions folder.
Apple MIDI Driver - this must go in the System Folder
PatchBay - this is available as a DA and an Application. I just use the Application and put it in...