Although Fibre Channel utilizes the SCSI protocol for block based disk I/O, Fibre also has the capability to run multiple protocols at the same time. The Fibre spec is very open, and the Fibre cables themselves are just the underlying transport that enable great distances between servers and storage,(up to 100km) and also enables storage consolidation for access by many nodes.
SCSI on the other hand only supports a max of 15 nodes per bus, is limited to 25 meters for differential SCSI and requires proper termination to prevent signal reflection. Fibre in a fabric topology can scale to thousands of nodes, is unlimited in the amount of storage being accessed, is tamper proof because it's optical, and enables things like LAN free backup, remote replication, wide area clustering, dual pathing, dual ported access, hardware based volume shadowing, etc.
This was first published in April 2001