IEEE 1394, called FireWire by its inventor, Apple Computer, is a type of interconnection generally used between a computer and its peripherals; it is not a local area network. Its main competitor is the universal serial bus (USB); it is generally faster but more expensive than USB.
FireWire remains faster than USB 2.0, and retains all the logical capabilities of SCSI, which does not. The Apple was a strong initial supporter of FireWire, but no longer supports it on new iPods, preferring USB 2.0. There is some irony here, because Apple's requirement for patent royalties discouraged other manufacturers, such as Intel, from incurring that cost. USB 2.0 also takes cheaper hardware.IEEE created the "1394 Licensing Authority" that charges vendors $0.25 per end user system, the money supporting IEEE.
It has had wide operating system support. Full support for IEEE 1394a and 1394b is available for FreeBSD, Linux and Apple Mac OS X operating systems. There are IETF specifications for running IPv4 and IPv6 over FireWire.
Microsoft Windows XP supports 1394a and 1394b, but requires a download and registry modification is available from Microsoft to restore performance, from the XP default of S100 to either S400 or S800. Microsoft Windows Vista will initially support 1394a, with 1394b support coming later in a service pack.
The original deployment used six pins, still much simpler than parallel SCSI, with two dedicated to providing power to an attached device. Sony's implementation, i.Link, uses a four-pin signal connector with a separate power connector. Be careful to keep connectors compatible.
IEEE 1394 has some advantages over comparable technologies. Like USB, it allows hot-swapping can supply power over its signal wires. Unlike USB, it allows direct communications between devices on the same FireWire system, rather than requiring resources on the main processor. Such direct communications, for example, might be useful for downloading video from a IEEE 1394 camera to an IEEE 1394 hard drive.
In the faster B version, it is being adopted in some real-time control systems, such as the F-35 Joint Strike Fighter. Aircraft control would be a plausible situation where direct device-to-device transfer is attractive.