This article is from the storage FAQ part2, by Rodney D. Van Meter with numerous contributions by others.
Rich Taborek of Amdahl has created an excellent web page on Fibre Channel at http://www.amdahl.com/ext/CARP/FCA/FCA.html. ftp ftp.network.com [Has draft Fibre Channel documents] playground.1.com [Has FCSI Fibre Channel Profiles] (rdv, 95/5/18 from Louis Grantham <Louis.Grantham@dalsemi.com>) Fibre Channel runs over coax or optical fibre (single or multimode), and even twisted pair. Fibre Channel comes in two basic forms -- Aribtrated Loop and switched fabric, which aren't (yet) interoperable. The host interfaces are rapidly becoming cheaper, but the switches are still expensive. Fibre Channel standards define several functional levels, from the physical interface up to the mapping to upper level functionality, e.g. how to do SCSI commands over FC. FC provides several "classes" of service, including dedicated circuit and acknowledged and unacknowledged datagrams. Can also be used for IP. (rdv, 96/10/28)