Transmitting several bits of data simultaneously using multiple lines (8, 16, 32, 64). The pathways between the CPU and memory are parallel, and they used to be parallel between the CPU and peripheral devices. For example, parallel ATA (PATA) was replaced with serial ATA (SATA); parallel PCI was replaced with serial PCIe. See SATA
Why the Change?
At increasingly higher transfer rates, it is more efficient to build channels that carry data over a single wire rather than 32 or 64. For more details, see parallel vs. serial
. Contrast with serial transmission
. See system bus