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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: barney on August 23, 2009, 09:21:06 PM

Title: What is the recommended ID # for SCSI HD?
Post by: barney on August 23, 2009, 09:21:06 PM
Hello, I was just wondering for an Amiga 2000 with one scsi drive and one CD Rom, what is the recommended HD id # and why.  Does one ID # give better performance to another?  Thanks.

Barney
Title: Re: What is the recommended ID # for SCSI HD?
Post by: tone007 on August 23, 2009, 09:48:48 PM
As long as you pick an ID that isn't in use, you're good.  One wouldn't perform better than another.
Title: Re: What is the recommended ID # for SCSI HD?
Post by: Zac67 on August 23, 2009, 10:11:08 PM
If you use ID 0 it might (very slightly) speed up the boot delay. (The last drive with the highest ID is marked with most RDB controllers. With only ID 0 present the device scan stops after that drive and starts the boot process a bit quicker than e.g. ID 6.)
Title: Re: What is the recommended ID # for SCSI HD?
Post by: Matt_H on August 23, 2009, 11:45:27 PM
Some Commodore controllers shipped with hard drives set to ID 6 by default, but it really doesn't matter at all.
Title: Re: What is the recommended ID # for SCSI HD?
Post by: JimS on August 24, 2009, 12:57:19 AM
I think a lot of drives were set by the manufacturer to 5 or 6 because those addresses used two jumper blocks. That way they didn't have to put the jumpers in a separate package... they could just ship them on the drive. Doesn't explain why they didn't use "3"... ;-)
Title: Re: What is the recommended ID # for SCSI HD?
Post by: Trev on August 24, 2009, 01:29:37 AM
On a bus with multiple devices, e.g. a hard disk, a scanner, and an optical drive, the device with the highest ID has the highest priority on the bus. Most host controllers have ID 7, making ID 6 the highest priority target device on an 8-bit bus. Google "scsi id priority" for more information.
Title: Re: What is the recommended ID # for SCSI HD?
Post by: barney on August 24, 2009, 02:45:03 PM
Thanks for the help.  I am going to set mine to 6 and see how it works out for me.  Thanks.

Barney