What are the advantages and characteristics of SAS interface

SAS(Serial Attached SCSI) Serial connection SCSI, It's a new generation of SCSI technology , And now popular SerialATA(SATA) The hard disk is the same , Are using serial technology to get higher transmission speed , And by shortening the connecting line to improve the internal space . So what are its advantages and characteristics ?

SAS Interface technology can be downward compatible SATA. say concretely , The compatibility of the two is mainly reflected in the compatibility of physical layer and protocol layer . At the physical level ,SAS Interface and SATA The interface is fully compatible ,SATA The hard disk can be used directly in SAS In the environment of , In terms of interface standards ,SATA yes SAS A sub standard of .

therefore SAS The controller can be operated directly SATA Hard disk , however SAS But it can't be used directly in SATA In the environment of , because SATA The controller doesn't work for SAS Hard disk control ; At the protocol level ,SAS from 3 There are two types of protocols , According to the connection of different devices, use the corresponding protocol for data transmission .

Among them, serial SCSI agreement (SSP) For transmission SCSI command ;SCSI Management Protocol (SMP) Used for maintenance and management of connected equipment ;SATA Channel protocol (STP) be used for SAS and SATA Data transmission between . So here 3 With the cooperation of two kinds of agreements ,SAS You can talk to SATA And part SCSI Seamless integration of devices .

In the system , every last SAS The port can connect up to 16256 Outside Equipment , also SAS Adopt direct point-to-point serial transmission mode , The transmission rate is as high as 3Gbps, It is estimated that there will be 6Gbps Even 12Gbps The high-speed interface appears .

 

SAS The interface of has also been greatly improved , It also provides 3.5 Inches and 2.5 Inch interface , Therefore, it can meet the needs of different server environments .

SAS rely on SAS Extender to connect more devices , Current extenders 12 Most ports , However, according to the board manufacturer's product R & D plan , There will be 28、36 The extender of the port is introduced , To connect SAS equipment 、 Host equipment or other SAS Extender .

I hope it can help you .