· ISA, which is old, slow, and limited, compared to the alternatives listed below. We hope that it is replaced by the following interfaces:
· PCI, which is the newer high speed multifunction I/O bus.
· AGP, which only is used for graphics adapter.
· USB, which is the new low speed I/O bus to replace ISA.
· Internal I/O ports (LPT, KBD, COM1, COM2, EIDE etc.).
If we focus on the right end of the illustration we approach the I/O units. Here you get a closer look at that:
As you see, there is room for a lot of units to be connected to the PC.
The PCI bus is the most loaded of all the buses. It is used for so many purposes that the output for the graphics adapter has been isolated on its own AGP-bus.
But still the PCI bus is heavyly loaded, connecting the system bus to the network controller and the various EIDE- and SCSI drives. Because of the high bandwidth of the FireWire bus, overall throughput of both interfaces would be improved by separating these. We hope to see a separate FireWire interface in future motherboard architectures.