A method of adding extra devices to a system by connecting them to each other in a chain, rather than connecting each device to the computer individually. In a SCSI configuration devices such as printers, hard disks, CD's, Zip drives etc. are connected together via a series of cables. UltraWide and Ultra2 boards can connect up to 15 SCSI devices simultaneously. SCSI-1, SCSI-2 & Ultra boards can connect up to 7 SCSI devices simultaneously. FireWire and USB work along similar lines, but with individual differances. With FireWire the devices are connected with identical cables with no restrictions, other than the maximum limit of 53 devices. USB devices cannot be daisy-chained as such. You can buy an external hub that will connect a set number of devices and then connect to another hub which will do the same with only 1 physical connection to the computer, for the first hub in the chain. The maximum number of devices for USB 127.