[KLUG Hardware] Re: Scsi

[Mike Williams]

>
>
>Date: Mon, 18 Nov 2002 23:25:32 -0500
>From: Thera <tvpeterson@cbpu.com>
>To: hardware@kalamazoolinux.org
>Subject: Re: [KLUG Hardware] Re: SCSI Question and Advice Request
>Reply-To: hardware@kalamazoolinux.org
>
>
>I'll remove the HDD jumper then. I was also confused because TFM says
>that one or more of the devices must enable power to the active
>terminator, and I wondered if maybe that's why they jumpered the HDD
>'SCSI Term ON'. I've googled a spec sheet that shows those header pins 
>as 'Enable SCSI Terminator', but I guess if it meant enable terminator 
>_power_ it would have said so. (there are no such-labeled pins on any of 
>the HDD headers). 
>
I'm a little rusty on the faster variants of SCSI, but I think the spec 
says that for Ultra 2, all devices are expected to provide power, where 
in earlier versions the controller and maybe the terminating drive would 
provide power.  It doesn't matter much, but I think it's cleanest when 
the devices that are terminating the chain provide power for the 
termination.  

>
>The mobo has on-board raid, so I'd gotten 3 of what I thought would be 
>identical add'l HDDs with RAID 1+0 in mind. Turns out though the brand 
>(IBM) and capacities are the same; the RPM, seek time, data rate,
>transfer rate, etc... are not. They DO however, have 'Termination Power 
>Enable' pins. So I'll use one of them. Just to be sure, I'll get them 
>working strung out on the floor before I intstall them and their cages.
>  
>
Always a good plan.  That must be nice mobo to have SCSI RAID onboard. 
 any idea what it is?

>>Controller card termination is
>>determined by how many of the card's connectors are used.  If you use
>>only one connector (internal, external doesn't matter), you want the
>>card's termination ON.  If you use 2 connectors you want termination
>>OFF.  Most cards that have more than 2 (external, narrow internal, wide
>>internal usually) require that you not use all 3 at once.
>>    
>>
>
>The SCSI controller is on-board the mobo, and is exactly as you describe 
>(1 ext., 1 int., 1 narrow int.) I'll be using neither external, nor
>narrow devices, so I'll enable termination on the controller end in the 
>BIOS.
>
>Thanks for your help :)
>
>Thera
>  
>
No prob.  good to get the cobwebs out of that area of my memory.