I have a 7-port USB hub, and need another port. Can I plug in a second 7-port hub into the computer? And if I ever need to . . . can I piggyback a new hub into my existing hub? What determines the number of USB ports a computer can handle?
If it matters, I have a G5 Mac.
In using 7 port hubs be aware that some (check your specs) are actaully a split of 5 US 2.0 ports and 2 USB 1.1 ports.
The maximum number of USB devices is 127 per host controller. A computer can have more than one host controller. Wiki explains it here.
And yes, you can daisy-chain hubs.
But speed will fall as devices share bandwidth.
I believe it’s also true that devices on any root hub will be forced to drop to match the lowest-spec device, so a USB 1.1 memory stick would slow down transfer of data from a Hi-Speed USB 2.0 external drive, if they’re both plugged in at the same time.