Question on Internal SCSI Drives

[RyanVM]

Hello, I've never had to deal with SCSI in depth before, and for the system I'm planning on building, I'm going to have a few internal Ultra2 SCSI drives (Yamaha CDRW 4414S and IBM Ultrastar 18GX). For a mobo, I'm planning to use the Tyan Thunder 100 with onboard SCSI (including Ultra2). Here's my question, are internal SCSI drives capable of daisy chaining like their external counterparts??? I ask because the Thunder only has one Ultra2 80 pin connector, obviously creating a problem with two devices. Thank you very much for your help.

Ryan VanderMeulen
rvand@sirus.com

[bighammer]

you have no worries.
The board comes with your 50 pin for your CDroms and the U2 for your Hard drives.
You only run into problems when using the UWscsi and cdroms on the 50 and 68 pin cables.
Even then, it's only the access that loses a little because they are on the same channel.
I'm running the P2B-LS and the Shuttle 649A.
Both sweet setups.
The Shuttle I think you will find is a better deal and it has adjustable voltages for each processor.
I did a review of it if you care to follow a link
http://www.lostcircuits.com/motherboard/hot649a

[RyanVM]

I'm sorry, I completely screwed up that last post. The Tyan mb has two 68 pin connectors and one 50 pin connector. The CD drive uses the 50 pin SCSI-2 port, leaving both 68 pin Ultra Wide SCSI ports. All the SCSI hard drives I'm looking at are using the Ultra2 interface. Am I correct in assuming that I'll be needing a SCSI card for the hard drive???

[This message has been edited by RyanVM (edited 02-21-99).]

[SNowlen]

Daisy-chaining internal SCSI devices is fine. You just get a cable with more than one connector and plug away. Your only limit is the number of total devices the mobo will accept. Within this limit you should have no problem daisy-chaining.

You have to be sure that each device, both internal and external, has a unique address set. The address is simply a switch setting on the back of each device and corresponds to a device number.

Also be sure that the last device, and only the last device, on both the internal and external chains is properly terminated. Most modern devices come with internal termination controled by a switch on the back of the device. For all but the last devices you set this to disabled. On the last internal and last external device you simply enable termination.

BTW, last litterally means the device at the very farthest end of the communcation cable for each daisy chain. Every chain must be terminated.

Finally, as long as you don't exceed the total device count your mobo accepts, then NO, you will not need a separate SCSI card for the HD. Just daisy-chain it and give it a unique address.

[This message has been edited by SNowlen (edited 02-23-99).]

[bighammer]

another quick note,
The two 68 pinners aren't the same. 1 is for U2 and the one next to the 50 pin is on the same channel as the 50 pin but UW 68 pin.
Hope your all set.

[RyanVM]

I just want to make sure that I have this all clear. If I were to buy an Ultra2 hard drive, I would be able to connect it to the 68pin connector, but I would not receive the 80mb/s bandwidth, correct?

The reason I'm so confused is that Tyan sells a dual Xeon board with onboard Ultra2, but they advertise their dual PII board as onboard UW-SCSI. I'm very unfamiliar with SCSI, so I apologize if I'm asking dumb questions, but hey, we're all here to learn, right?

Ryan VanderMeulen
rvand@sirus.com

[bighammer]

UW and U2 are different.
U2 is at up to 80.
UW is up to 40.

[RyanVM]

k, that's what I thought. I guess I'll just have to wait for the Intel L440GX+ Server Board :-)

developer.intel.com/pressroom/archive/releases/cn022299.htm (http://developer.intel.com/pressroom/archive/releases/cn022299.htm)

What can I say, I really like the 6/1/1 configuration, even if it is two 66Mhz PCI and four 33Mhz PCI slots....

Ryan VanderMeulen
rvand@sirus.com

[This message has been edited by RyanVM (edited 02-27-99).]