Let me ask a dumb SCSI question, but how can you get up to 15 devices.....

[compuwiz1]

When you have only 0-3 SCSI ID's??? I have a fourth drive I would love to install.

I have a CDRW, DVD and 2 Cheetahs, and 1 IBM LVD already and I want to add back in my other IBM LVD, but I have installed the DVD taking the ID that the IBM used to occupy. This is probably dirt simple, but I don't build scsi stuff day in and day out.

 

[Adul]

?? care to explain that again? Did you set the ids on your drives and stuff?

 

[compuwiz1]

Yes, I set the ID's on the drives. But, how can you get more than 4 drives? If any of them share the same ID, I get lockups.

 

[Adul]

how do you set the ids on your drives? Are they jumper blocks? Cant you have them on auto ID? I know my plextor drives do that.

 

[dowxp]

hmm, my controller searches both channels for 15 ids. does yours have an auto search function? i technically can have 28 devices [2 are for controller]...

 

[bacillus]

hmm, your scsi card should be id7, your boot drive id0, cd & cdrw ideally id 4 & 3.
your new hdd if it isn't a boot drive should get id1!

 

[compuwiz1]

Auto...hehe, who would have figured? I'll look at it tomorrow. Someone who helped me set the system up originally told me I had to give them each their own ID. That would be fine with 3 or 4 drives. :Q <<<<I was really a computer newbie then.

 

[bacillus]

<< Someone who helped me set the system up originally told me I had to give them each their own ID. >>


that's correct info!

 

[compuwiz1]

Ok, so that is correct info, then can drives share the same ID?

 

[EricHagen]

Normal drives cannot share the same ID.

There is a sub-section of the SCSI standard that allows for the POSSIBILITY for drives to share IDs using LUN values (logical unit number), but most drives don't impliment LUN mapping.

A &quot;narrow&quot; SCSI device supports 8 channels (7 plus the controller) and &quot;wide&quot; SCSI supports 16 channels (15 + controller).

Why are you thinking you only have 4 IDs?? Do your drives only have that many? It is customary to put the drives on the lower numbers since the ID numbers are usually used for boot-priority and lower numbers usually have higher bus priority, but they will work fine on any channel provided they're not sharing.

Cheers,
Eric

 

[Barrak]

To set IDs on drives normaly you use jumpers. Normaly you have 4 pairs of jumpers. The values of pairs 1 -4 are 1,2,4,8 respectivly. If you do not connect the jumpers they = 0 . So if you have jumper 1 closed and the rest open the ID of the drive is 1. If you have pairs 2 and 4 closed the ID of the drive is 10. If pairs 1,3,and4 closed it would be 13. So using the pins you can go from 0 to 15. Some older drives only had 3 pairs, so you could only go from 0 to 7. One ID (normaly 7) has to always be set aside for the controler.

Hope it helps

 

[Ben]

Just check the documentation from the manufacturer to find out the correct way to set the ID number. It's going to be a scheme exactly like Barrak says and there are some limits like Barrak and EricHagen pointed out.

You've got plenty of ID's left to install what you have and much more.

 

[Radboy]

scroll down near the end of this page, to the 'scsi address settings' .. where it shows the jumper block.

you only have scsi address settings 0-3, *but* you have numerous different ways to jumpers those settings .. allowing you to set scsi IDs to anything from 0 to 15, including 8, 9, 10, 11, etc.

does that help?

no, you can't have any two devices sharing the same scsi id. that's a golden scsi rule.

 

[compuwiz1]

Radboy, that will be helpfull. I am tearing down the system and going to upgrade the mobo soon. I have not been in there for many months, but I'm sure that info will help.

Thanks again!

 

[Rellik]

Compuwiz, you are misreading the jumper section of your drive.
I know it is irritating, but what you see as ID 0 to ID 3 is NOT the correct jumper block. Check the IBM page for settings. You can set your ID from 0 to 15, with the exclusion of 7 which is the standard for the controller. The boot drive DOES NOT NEED TO BE ID 0! It is a common misstake. ID´s will be read in a certain way (read Gary´s SCSI FAQ) but the bootdrive is set as DRIVE 0 which is not the same as ID 0. You can have your Boot drive at ID 2 configured as DRIVE 0, the secondary as Drive 1 etc..

 

[Radboy]

I've seen ppl have problems when trying to set their boot drive at a SCSI ID other than 0.

Like Rellik says, you should be able to boot from *any* SCSI (by setting it in the SCSI bios) .. 'should' is the key word in that sentence.

FWIW.

Glad to help. This might help, too.