no... as it was explained to me (and perhaps i misunderstood) if say you have a usb printer that's sitting there unused at the time... some portion of the bandwidthis allocated to that device just incase you start to use it because of it's serial nature... where FW is paralell and the "smart"devices simply extract what info it needs...
*shrugs*. I suppose that's remotely possible. That would depend on the printer. Generally speaking, though, I would not expect a USB printer to use any bus bandwidth except possibly the driver occasionally polling it for ink levels.
In general, USB (and FireWire) devices are bulk devices, which means they don't get any bandwidth reservations, merely getting whatever is available whenever the computer sends a message to the device and/or asks the device to send it something, and getting delayed as much as is needed until a free time slot on the bus becomes available. Unfortunately, some early USB audio devices were also bulk devices, which is one of the reasons USB audio got a really, really bad rep there for a while.
BTW, FireWire is definitely not a parallel bus... well, unless you count loops in a poorly wired setup.
The type of communication where a device requests a reservation is known as isochronous communication, which literally means "equal amounts of time". In USB and FireWire, every second on the bus is basically diced up into time slots of equal length. Each of those slots can be used for a message sent to a device or received from it (or in the case of FW800/FW1600/FW3200, one sent and one received packet per slot). With isochronous communication, a device declares that it needs a block of N slices, and that it will need one of those blocks again after every K slices until the device is deactivated or its settings change. In essence, this means that it reserves a certain amount of bandwidth, though we generally think of it more as time slices rather than bandwidth since it is a stream of bits, not a bunch of analog signals multiplexed on the same wire... but I'm being a little pedantic here.
Audio (and video) devices typically use isochronous communication. Normally, the only devices that take bandwidth whether they are in use or not are isoch devices, and even that isn't purely true. A USB device won't send data unless the driver is requesting it. Unload the driver, and even an isoch data stream goes away. Thus, for some types of devices (webcams, for example), the device typically only sends data when requested. For audio devices, however, usually the driver is always active. YMMV.
Human interface devices (a.k.a. HID; anything with buttons) are also isoch devices, at least in the USB world. So your mice and keyboards and stuff are constantly wasting bandwidth as the computer asks "Has this jerk pressed a key yet?" over and over and over. A FireWire HID device, if such a thing existed (and I guess they probably do to some degree), would not likely be isoch because the device would have the ability to send a message to the computer only when a button is actually pressed.
