The following lines were added (+) and removed (-):
SCSI drives use a processor for executing commands and handling the interface and a separate processor controlling the head positioning through servos. ATA drives use a single processor these functions. This can lead to an efficiency gain when using SCSI drives in a high demand setting, such as a web server. SCSI drives tend to outlast IDE/SATA since there is less physical movement needed to retrieve data under certain conditions. However, new high end SATA RAID adapters can prove to be equally as efficient for most applications. == SAS ==* '''Serial Attached SCSI'''SAS are drives using the SCSI command set and are basically the next generation of SCSI technology. A SAS controller can be used to connect SAS drives and SATA II drives. The SAS bus is point-to-point while the SCSI uses a multidrop bus. Many more devices can be attached to a SAS controller than a SCSI controller. NL-SAS, or Nearline SAS, are a class of enterprise level SAS drives.Since SATA II includes performance improvements that challenge the advantages of SCSI, SAS technology has been introduced to extend the capabilities of SCSI, offering SAS-harddisks with spindle speeds of 22,000 RPM. SAS offers data transfer rates in excess of 3 gigabits per second (Gbps) with potential rates of 10 Gbps or more. SAS will replace regular parallel SCSI bus technology and offer compatibility with SATA II drives. SAS drives do not have to be terminated like parallel SCSI, have higher speeds, but still use the SCSI command set.