Busses vs no busses

One of the most amazing things I've witnessed in the computer evolution is the growth, and death, of busses. Some, like Q-bus and S-100 are pretty simple, others like SBus and the switching fabric that constitutes the SparcServer 490 are much more complex. When asked once why I prefer the Q-bus 11's and Vaxen my answer is always because I can get lots of I/O to do neat things for those busses. (I'm writing a program for the PDP-8 to control an LED sign using a couple of 12bit parallel i/o cards. ) But the trend in PC's has gone to fewer and fewer "slots" and soon will be no slots. I thought that the bus was dead until I realized that USB has the same bandwidth as Q-bus and FireWire has much better bandwidth. So presumably we'll see some interesting I/O devices that use these busses in the future. --Chuck