The I/O bus from the CPU to the peripherals is a parallel bus (16, 32 or 64 wires, etc.). Although sounding similar, a serial bus differs from a serial port. Both use serial transmission ...

What also makes PCIe interesting is that it replaces the widespread use of parallel buses with serial links. Instead of having a bus with a common medium (traces) to which multiple devices connect ...

there is an industry-wide mega-trend to migrate the multi-drop parallel buses to point-to-point serial buses. For example, the vintage IDE bus is being replaced by SATA (Serial ATA) and the parallel ...