SAS or SATA 3

[StimulusDanny]

      So I was looking through some HDDs and I saw the same type of HDD (Seagate Constellation 4TB), but one was with SAS and another one with SATA 3. Now I'm really confused :wacko:  beacuse I've never heard of anything like SAS on an HDD before.   

  

      Could someone please care to explain this to me? And tell me which one is better? Thanks! 

 

 

[Volbet]

Theoretically SAS is better, but unless you have a RAID controller with SAS support or a server grade motherboard, you can't use it. It's a completly different electric protocol than SATA.

If I were you I would buy the SATA drive. It's guranteed to work with your motherboard (unless your motherboard is very old)

[StimulusDanny]

Alright! Thank you very much! 

[IdeaStormer]

Theoretically SAS is better, but unless you have a RAID controller with SAS support or a server grade motherboard, you can't use it. It's a completly different electric protocol than SATA.

If I were you I would buy the SATA drive. It's guranteed to work with your motherboard (unless your motherboard is very old)

 

Different Electric protocol ? :wacko:

 

Different data interface! But SAS is backward compatible with SATA and way better (SAS).

 

Some Ref's: http://www.turbotekcomputer.com/resources/small-business-it-blog/bid/57900/SATA-vs-SAS-What-is-the-difference

http://www.differencebetween.com/difference-between-sata-and-vs-sas/

http://blog.lewan.com/2009/09/14/sas-vs-sata-differences-technology-and-cost/

[Volbet]

Different Electric protocol ? :wacko:

 

Different data interface! But SAS is backward compatible with SATA and way better (SAS).

 

Some Ref's: http://www.turbotekcomputer.com/resources/small-business-it-blog/bid/57900/SATA-vs-SAS-What-is-the-difference

http://www.differencebetween.com/difference-between-sata-and-vs-sas/

http://blog.lewan.com/2009/09/14/sas-vs-sata-differences-technology-and-cost/

SAS and SATA use two different kinds of data protocols. You could call them interfaces, but I just thought it would sound like I refered to the cables.

To quote from one of the links in one of your sources.

SAS drives are built to a higher standard than SATA drives, but are more expensive. They use the SCSI protocol  and use a higher voltage making them easier to be used in servers that have backplanes rather than ribbon or cable connectors.

http://www.atlantavdi.com/sas-vs-sata-whats-the-difference/

The SCSI protocol and the SATA protocol are very different

It is true that SAS is micro compatible with SATA. However, that is becuase SAS controllers are also able to run the SATA protocol. Not becuase they are intercompatible.

There are also some difference with the bus on the controller side, but i felt like that was going into too much detail for a simple question. 

[IdeaStormer]

SAS and SATA use two different kinds of data protocols. You could call them interfaces, but I just thought it would sound like I refered to the cables.

To quote from one of the links in one of your sources.

http://www.atlantavdi.com/sas-vs-sata-whats-the-difference/

The SCSI protocol and the SATA protocol are very different

It is true that SAS is micro compatible with SATA. However, that is becuase SAS controllers are also able to run the SATA protocol. Not becuase they are intercompatible.

There are also some difference with the bus on the controller side, but i felt like that was going into too much detail for a simple question. 

 

So then, why does this work?

 

[Volbet]

So then, why does this work?

Becuase the internal mini SAS connector is the same as a SATA connector. This is why you can connect a SATA drive to a SAS controller. 

The difference is not with the cable (not with this cable atleast). The difference is the software and hardware at either end of the cable.

[IdeaStormer]

Becuase the internal mini SAS connector is the same as a SATA connector. This is why you can connect a SATA drive to a SAS controller. 

The difference is not with the cable (not with this cable atleast). The difference is the software and hardware at either end of the cable.

 

Dude, you are so wrong, please re-read the references. You can plug in SAS to SATA and SATA to SAS, well at least I can for some odd reason but you can't.

[Volbet]

Dude, you are so wrong, please re-read the references. You can plug in SAS to SATA and SATA to SAS, well at least I can for some odd reason but you can't.

Yes the connectors, and connector inteface, are the same. But if you plug a SAS drive into a SATA controller it won't work,

I know plebty of people rhat use SAS connectors for their SATA drives, becuase they feek they fit better. And it does work that way. 

A picture of SATA and SAS

As you can see the pins are exactly the same. 

My point is that a SAS drive won't work in a SATA controller, because the SAS drive sends a data signal that the SATA controller can't read.

It would be if I began writting in Aka-Bo insted of English. It would be pretty hard, if not impossible, for you to understand. However I would still be conveying information, you just wouldn't be able to understand it.

[IdeaStormer]

Yes the connectors, and connector inteface, are the same. But if you plug a SAS drive into a SATA controller it won't work,

I know plebty of people rhat use SAS connectors for their SATA drives, becuase they feek they fit better. And it does work that way. 

A picture of SATA and SAS

As you can see the pins are exactly the same. 

My point is that a SAS drive won't work in a SATA controller, because the SAS drive sends a data signal that the SATA controller can't read.

It would be if I began writting in Aka-Bo insted of English. It would be pretty hard, if not impossible, for you to understand. However I would still be conveying information, you just wouldn't be able to understand it.

 

Psst..

 

http://linustechtips.com/main/topic/219416-sas-or-sata-3/#entry3015808

[Volbet]

Psst..

 

http://linustechtips.com/main/topic/219416-sas-or-sata-3/#entry3015808

I think the two of us are talking completly past eachother. I don't care about the cable, I care about the protocols behind it. 

The cable is of no concern to me, the signal is.

[FizzyFantom]

Psst..

 

http://linustechtips.com/main/topic/219416-sas-or-sata-3/#entry3015808

I thought that I ought to help you out here. SAS drives cannot be understood by a SATA controller, they speak in different languages. SAS controllers understand both SAS (SCSI) and SATA drives, but SATA controllers only understand SATA drives.

 

http://www.tomshardware.co.uk/forum/257100-32-drives-work-sata-connections

 

the SAS controller knows what to do with a SATA drive but the reason you can't use a SAS drive on a SATA controller is that the SAS drive speaks a different language (ie. SCSI Command Set)

 

http://arstechnica.com/civis/viewtopic.php?t=76013

 

SAS controllers can handle both SAS and SATA drives. SATA controllers cannot talk to SAS drives, only SATA drives.

 

I can't account for the existance of that cable, it seems somewhat odd, but it definitely won't let you use a SAS drive with a SATA controller.