Small Computer System Interface (SCSI) is a term that refers to a set of industry-standard specifications for connecting and transferring data between computer systems and peripheral devices. There are several synonyms for SCSI that are commonly used, including SAS (Serial-Attached SCSI), SCSI II, SCSI III, and SCSI Ultra. SAS is a newer, faster version of SCSI that uses smaller connectors and supports higher transfer rates. SCSI II is an older version that supports data transfer rates of up to 10 MB/s, while SCSI III supports rates of up to 40 MB/s. SCSI Ultra refers to SCSI devices that support data transfer rates of up to 80 MB/s. Regardless of the version, SCSI is an essential technology for data storage and transfer in modern computer systems.