Pin configuration for hot swappable ultra320 SCSI HDDs

I'm looking at purchasing a Tyan Transport GT24 (B2891)

It says that it "supports up to 4 hot-swappable ultra320/160 SCSI HDDs" but I'm wondering which hard drives will work with this. It's my understanding that there are two pin configurations for ultra 320 SCSI HDD.

Which pin configuration do I need for this Tyan system?

I'm looking at getting some Seagate Cheetah 36GB Ultra320 SCSI 15,000rpm HDDs.

ST336754LC (SCA80 - 80 pin),1081,659,00.html

ST336754LW (68 pin),1081,660,00.html

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Lee W, MVPTechnology and Business Process AdvisorCommented:
I didn't realize this was a complete server and not just the motherboard.

the page labeled 62 (70 of the pdf) shows a picture of the SCSI backplane and it is clearly SCA, so you want the SCA drives.
Lee W, MVPTechnology and Business Process AdvisorCommented:
There are adapters to go both ways.  Which drive depends on the case you put it in.  If the case has a SCSI backplane, then you get the SCA 80 pin drives.  If you don't have a SCSI backplane then you want the 68 pin drives.

A backplane is essentially a board that has the connectors on it - power is connected to the board and the drives connect to the SCA connectors on the board - this is what makes them hot-swap or not (as well as controller support).
Lee W, MVPTechnology and Business Process AdvisorCommented:
If your case supports them, this is just one example of a SCSI backplane:

It would be positioned within the case to align with hard drive slots, usually mounted in sleds, that slide in and connect to the connectors on the backplane.  If your case does not have these, you want the 68 pin drive.
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ProfWilliamWangAuthor Commented:
The manual for the Tayan Transport GT24 (B2891) is here.

I believe that it has a back panel but the Seagate guy I got on to said that sometimes manufactures put a 68 pin config on their back panels. I'm sure this isn't the case with Tyan but I'm trying to make sure before I buy.

Thanks for your help leew, could you have a quick look at the manual and see what you think?
ProfWilliamWangAuthor Commented:
ProfWilliamWangAuthor Commented:
Thank you very much for your help leew.

Points awarded accordingly.
ProfWilliamWangAuthor Commented:
You'll never guess. I finally got a response from Tyan:

Dear Sir:
The SCSI pin of B2891GT24 are 68 pins, thanks.

Best regards,

Oh my goodness! These SCSI HDD are a mine field.
Lee W, MVPTechnology and Business Process AdvisorCommented:
Hmmm... that picture is clearly SCA 80 pin backplane.  I understand wanting to believe support, but I'm not sure I would given that picture.  They could mean the cable that connects from the SCSI controller on the mainboard to the backplane is a 68 pin - that I would expect... but the backplane pictured is clearly SCA.  I'm inclined to suggest you get SCA anyway.  You can adapt SCA to 68 pin, but you can't adapt 68pin to SCA (at least not nearly as easily).  For example:

Otherwise you could be stuck with the wrong drives or have to wait longer as you ship them back and exchange them for SCA models (if you bought 68 pin models.

And the adapters work fine - I have one in my desktop system connected to a 73GB SCSI drive.
ProfWilliamWangAuthor Commented:
I've been doing a little more digging. It looks like the SCSI Controller is a  Tyan M7901 SO-DIMM:

Which has a Adaptec® AIC-7901X chip.

This is clearly where the 68 pin is. However, like you, I do believe that at the HDDs it will be a 80 pin connection. I think what might happen (this is speculation) is the backplane will accept the 68 pin and power from else where and the HDDs will plug into a 80 pin power and SCSI SCA80 plugs.

So I think you are right. I've asked Tyan support for clarification, but who knows how long that will take.

If Tyan get back to me I'll post up what they tell me.

If you happen to be in the US and this is a local number for you:

510.651.8868 (Tyan sales)

It'd be great to get some answers from the horses mouth.
ProfWilliamWangAuthor Commented:
OK I've got a response back from Tyan and it looks like you were right and my guess was correct. The response I got was in relation to the controller.

They have confirmed that the backplane is 80 pin.

Thank you again for your help leew, now on with my server build.
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