Western Digital has expanded its line of enterprise-class Serial Attached SCSI hard drives. The 2.5" S25, better known to enthusiasts as a sled-less VelociRaptor, has added 450 and 600GB capacities to go along with the 147 and 300GB models already available. All four capacities share the same 10,000-RPM spindle speed and 6Gbps SAS interface. However, the new models offer twice the cache (32MB) of their predecessors.
Speaking of new additions, WD has introduced a couple of SAS offerings in its 3.5" RE family. The RE line has much in common with Caviar Black desktop drives, including a 7,200-RPM spindle speed and 32MB of cache. As the RE SAS name implies, the drives have 6Gbps Serial Attached SCSI interfaces, just like the S25. The RE's larger 3.5" form factor leaves room for quite a bit of additional capacity, though. Drives will be available in one- and two-terabyte capacities.
Like other RE models, the new SAS units undergo more stringent testing than desktop drives and incorporate RAID-specific features like RAFF (Rotary Acceleration Feed Forward) compensation for rotational vibration. Those perks also appear in low-power RE drives based on the Caviar Green. The 5,400-RPM RE-GP family hasn't been upgraded to Serial Attached SCSI interfaces just yet, though.