Serial-attached SCSI (SAS) is a method used in accessing computer peripheral devices that employs a serial (one bit at a time) means of digital data transfer over thin cables. The method is specified in the American National Standard Institute standard called Serial-attached SCSI (Small Computer System Interface), also known as ANSI/INCITS 376-2003. In the business enterprise, serial-attached SCSI is especially of interest for access to mass storage devices, particularly external hard drives.
Serial-attached SCSI offers advantages over older parallel technologies. The cables are thinner, and the connectors are less bulky. Serial data transfer allows the use of longer cables than parallel data transfer. Problems related to crosstalk are less likely in serial interfaces than in parallel interfaces, because there are fewer conductors in the cables. The hardware for serial interfaces is less costly than the hardware for equivalent parallel interfaces.
SAS offers data transfer rates in excess of 3 gigabits per second (Gbps) with potential rates of 10 Gbps or more. Serial-attached SCSI is said to offer an ideal solution for businesses with substantial storage, backup, and archiving demands.
Devices that employ SAS are compatible with serial ATA (Advanced Technology Attachment) devices. In addition, SAS products are compatible with devices that employ earlier SCSI technologies. External disk drives, host adapters, and expanders were the first devices to employ SAS. The technology is expected to expand to printers, scanners, digital cameras, and other peripherals.