Date   : Tue, 29 May 2012 11:21:12 -0500
From   : jules.richardson99@... (Jules Richardson)
Subject: Setting jumpers SCSI IDs

On 05/25/2012 02:40 PM, Pete Turnbull wrote:
> On 25/05/2012 10:44, Phill Harvey-Smith wrote:
>> On 25/05/2012 10:06, Jim Hearne wrote:
>>>> putting a jumper on makes it a value of '1',
>>>> and getting it off makes it '0'
>
> Pretty standard for SCSI, especially drives.
>
>> Yes generally SCSI controller/ host adapter has id 7 and drives have ids
>> 0..6.
>>
>> However if you have an SGI unix box, they decided to have the controller
>> as id 0 and drives as 1..7 which can be confusing if you are used to
>> what everyone else uses.....
>
> Actually it would be more accurate to say that most non-PC computer
> manufacturers use 0 for the controller and 1-7 for the peripherals,
> which can be confusing if you're only used to PCs :-)

I think Apple also used #6 for the HBA at one point in time. I'm not sure 
if they actually supported 8 devices on the bus (inclusive of HBA at #6) or 
if no device could be placed at ID #7.

Incidentally, I don't recall ever seeing a SCSI device where the removal of 
an ID jumper signified a '1' and the presence of one indicated a '0' (which 
I think Johan was saying has typically been his experience) - it's always 
the other way around (all jumpers off = ID 0, and adding jumpers signifies 
bit-set in that position).  That's not to say I haven't seen them "Johan's 
way around", just that I don't remember it ;)

cheers

Jules