SAS and SATA flexibility The SAS architecture lets system designers install SAS drives, SATA drives or a mix of both in the same box. This flexibility greatly broadens the range of storage solutions available to technology managers, allowing them to choose devices based on reliability, performance and cost attributes—not interface compatibility. In addition, HP hard drives come with specific firmware enhanced for performance and integration into an HP system. All firmware is thoroughly tested to provide superb integrity, error recovery and functionality. SAS supports three protocols to handle device commu - nications. After power up or restart, the SAS domain goes through an initialization sequence to determine the proper protocol to communicate with a variety of devices: - Serial Management Protocol (SMP) manages the pointtopoint topology of expanders. - Serial SCSI Protocol (SSP) allows the controller to communicate with SAS devices and existing SCSI software.- SATA Tunneling Protocol (STP) allows SAS controllers to communicate with SATA devices.
