Serial Attached SCSI
We manufacture high quality next-generation SAS cables, a interface standard for SCSI-based systems, designed to
replace the SCSI parallel interface with much faster, more flexible, 3Gb/s Serial Interface while maintaining the robust nature of the SCSI Command Set.
SAS Cabling FAQ
Ultra320 SCSI has been released allowing for a 320MB/sec data transfer rate. The SCSI specifications allow for the future release of
Ultra640 as well doubling the transfer rate again. Ultra 640 is however will not eventuate due to issues with "data skewing" and the release of Serial Attached SCSI
The release of Serial
Attached SCSI (SAS) overcomes the problem of "skewing"
of parallel data bits on the cable by running all communications via a Serial interface. The SCSI committees are working on a future development of the Serial standard.
Serial Attached SCSI (SAS) is
pin compatible with SATA
allowing SATA drive caddies to be used in Serial SCSI. SAS controllers can also use SATA drives. Current SAS controllers operate at 3Gb/sec to 6Gb/sec and will scale up to 12Gb/sec in the next few years . A SAS controller can have up to 128 devices attached. There can be multiple controllers in a SAS configuration allowing for both redundancy in case of failure and increased performance.
main difference between SAS and SATA
continues to be the higher spindle speeds, faster access times, and higher transfer rates available in SAS drives. SAS continues to be the high performance storage system, while SATA arrays provide cost effective mass storage.
In another area is the release of iSCSI. This allows for the SCSI protocol to be used over an IP network. This means that iSCSI drive arrays can be consolidated at central points and accessed by servers anywhere in the room, building, country or world. It allows a SAN equivalent without the cost of Fibre networking and Fibre switches. Some of the iSCSI releases actually use SATA or SAS drives in the array, with the unit providing a iSCSI interface to the network. This allows for
large amounts of cheap storage to be implemented anywhere on the network. it does however require some form of storage management system which can add significantly to the cost.