High speed serial interface defined by Apple Computer in 1994. FireWire is a trademark; the interface may be referred to as IEE1394 withut paying royalties to Apple. FireWire allows the attachment of up to 63 devices to a single controller and allows for hub or daisy-chain topolgies. It was designed as a next-generation replacement for SCSI and is used to connect cameras, AV equipment, hard drives and optical drives to computer equipment.
FireWire can operat at 100,200,400 and 800 Megabits per second and there are 4, 6 and 8 pin variants on the physical connectors.
Sony have their own branding for FireWire - they refer to it as i.Link
The iMac has two FireWire ports on the back.