SCSI pin number?

Four recent versions of SCSI, SSA, FC-AL, IEEE1394, and Serial Attached SCSI (SAS) break from the traditional parallel SCSI standards and perform data transfer via serial communications. Although much of the documentation of SCSI talks about the parallel interface, most contemporary development effort is on serial SCSI. Serial SCSI has number of advantages over parallel SCSI—faster data rates, hot swapping, and improved fault isolation. Serial SCSI devices are more expensive than the equivalent parallel SCSI devices but this is likely to change soon.