From: ksi@koi8.net   
      
   Don Y  wrote:   
   >>>> The opposite is possible -- SATA drive can be plugged into SAS receptacle   
   so   
   >>>> those are SAS/SATA physical connectors.   
   >>>   
   >>> All of my backplanes are SAS/SATA (though not mix and match).  So, I don't   
   see   
   >>> the value of keeping any of the SATA (only!) sleds.  I can, of course, use   
   them   
   >>> in the existing backplanes but see no advantage to keeping them over an   
   >>> equal number of the SAS/SATA sleds.   
   >>   
   >> Yep, there is no reason unless you have SATA-only device and a box of SAS   
   >> drives that you might accidentally plug in there :)   
   >   
   > But, as I can affix SAS drives to the SAS/SATA sleds, wouldn't the sleds   
   > be accepted by a SATA-only backplane?  Or, am I interpreting this from the   
   > wrong point of view?   
      
   Nope, they won't be accepted. The SAS/SATA sled has SAS connector and   
   SATA-only backplane has that protrusion that is going into the slot in a   
   SATA connector. That protrusion will not let a SAS/SATA sled to be plugged   
   in because of that protrusion and no slot for it in the connector.   
      
   The SAS and SATA connectors are identical in all respects except that slot   
   that is only present on SATA plug.   
      
   >   
   > I.e., the mounting holes for SAS and SATA drives are identically placed.   
   > So, I can mount a SATA or SAS drive on a SATA sled or a SAS/SATA sled.   
   > (there's nothing preventing the SAS from being mounted on the SATA-only   
   > sled).   
   >   
   > So, I *could* "force" that sled into a SATA-only backplane.   
      
   There is no protection from a good sledgehammer blow, ya know...   
      
   > I.e., the better solution would have been for the drives to have different   
   > mounting hole patterns so you could NOT mount a SAS drive on a SATA-only   
   > sled and have the connectors trying to mate.  As it stands currently,   
   > the sleds require the person who affixes the drive to observe the   
   > markings on the sled to avail himself of that protection.  (?)   
      
   You can plug a SATA drive into SAS/SATA backplane but not vise versa. Most   
   (if not all, not sure) SAS controllers also support SATA drives so there is   
   nothing wrong with plugging a SATA drive in a SAS backplane. On the other   
   end, almost(?) none of SATA controllers support SAS so it might be a problem   
   plugging a SAS drive into SATA-only backplane. This is why those have that   
   protusion in the receptacle and slot in the plug. That makes plugging a SAS   
   drive into such receptacle impossible.   
      
   Making DIFFERENT connectors for SAS and SATA is a bad idea. SAS controller   
   or backplane can work with SATA drives so it makes sense to have the   
   connector IDENTICAL. If they had been different it would've been very   
   awkward to make a SAS/SATA sleds/backplanes if possible at all.   
      
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