SCSI 
Small Computer System Interface 
A family of parallel interface standards for adding devices such as disk drives, printers, and scanners to a computer (parallel refers to the ability to transmit multiple streams of bits at the same time). This interface standard was originally developed for the Macintosh but has long since been adopted by most personal computers. By using SCSI (pronounced "skuzzy"), you can daisy-chain up to 16 devices to your computer's SCSI port. It's a robust standard, transferring data at speeds ranging from 5MB to 160MB per second, depending on the version.