Over the years we've seen nearly every type of hard drive come across our bench. IDE, SATA, SCSI, SSD, Hybrids, SAS....we've beta tested and reviewed them all. New technology has come and gone, but where is the speed? Even with SATA 2.0 and SSD technology, it still seems like the slowest component in a computer is the hard drive. Hard drives are truly the one device that is always behind and that statement has stood true since hard drives were invented. Regardless, hard drive technology has improved dramatically over the years and there are some really great things in the pipe that will change storage devices forever.

So how about right now? What is available to us right now that is bigger, better and faster? How about SAS 2.0? Right now, SAS 2.0 with 6Gb/s data transfer speeds is the ultimate solution to the data bottleneck. The first ultra fast Serial Attached SCSI (SAS) hard drives were released about 2 years ago to replace SCSI and now it's time for an upgrade. The ALL NEW Seagate Constellation ES hard drives with 6Gb/s (SAS 2.0) interface is here and ready to make some big waves in the storage market!

What is Serial Attached SCSI (SAS)?

Serial Attached SCSI is a data transfer technology designed to move data to and from computer storage devices. It is a point-to-point serial protocol, rather than multidrop, that replaces the parallel SCSI bus technology that first appeared in the mid 1980s and has been in use in corporate data centers ever since. The SAS interface offers backwards compatibility with Serial ATA drives, however SAS drives may not be connected to an SATA interface due to compatibility reasons. Physically, a SAS drive can not be connected to a SATA interface due to the SAS backplane and keyway on the SAS hard drive itself. For more detailed information on Serial Attached SCSI, please refer to the article here.

The SAS Vs. SATA Interface

Look closely at the two hard drives below. The top hard drive is an SATA hard drive and the bottom one is a SAS hard drive. The SAS hard drive has a solid bridge or "backplane" between the power and signal ports which prevents the accidental use of a standard SATA cables on a SAS hard drive.

SAS interface cards offer backwards compatibility with Serial ATA drives, however SAS drives may not be connected to an SATA interface cards due to compatibility reasons. Physically, a SAS drive can not be connected to a SATA interface due to the SAS backplane and keyway on the SAS hard drive itself.

Cabling

SAS cables are physically different than SATA cables. Pictured below is Internal Mini-SAS to 4x SAS cable for internal SAS/SATA raid interface cards. Unlike the standard SATA cables that have separate data and power cables, SAS cables have the data and power cable integrated into one cable. SAS cables will work with both SAS and SATA hard drives.

Slowing Down the RPMs

In the past, SCSI and Serial Attached SCSI drives have spin speeds that far exceed the5400 and 7200 rpm we see in the standard desktop hard drive with speeds of 10,000 and 15,000 rpm. A faster spin speeds usually means better performance, but that also means the drive is much, much hotter. So hot in fact that I've left my burned in finger print on a few 15k SCSI drives in my time. On the Constellation ES, Seagate's technology has improved dramatically. So much in fact they have slowed down the spin speed to 7200 rpm, lowered power consumption, lowered heat output, yet they have INCREASED performance. A more environmentally friendly hard drive with better performance? Now you've got my attention...