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Re: ARGH, weird SCSI I/O errors on second/third drive on Debian/PPC

On Sat, 28 Dec 2002, Michel Lanners wrote:

> On  27 Dec, this message from Jessica Blank echoed through cyberspace:
> > On Fri, 27 Dec 2002, Michael D. Crawford wrote:
> > 
> >> Could the original drive still be terminated after you have installed the other 
> >> drives?  It is probably worse to have extra termination than to have none at 
> >> all.  Make sure you've got it right.
> > 
> > The original drive was NOT installed at the end of the chain. (The 
> > original Apple-branded CD-ROM drive was...) So I don't think termination 
> > would be an issue for this drive, no?
> How did you install two more drives in the 7300? Did you remove the
> CDRom?


> Anyway, your SCSI chain needs to _physically_ look like this:
>   Host--------------------------------------------last device
>         |         |         |         .....|
>       Device    Device    Device         Device
> Only the last device must have termination, none of the others must have
> (well, the Host does, but that's automatic).
> So, verify your SCSI cabling in the first place. All other devices
> except the physically last one (i.e. at the end of the flat cable) need
> to have termination switched off. Verify that with the help of the
> manufacterer's jumper info.
> Then, you can try to use another drive providing termination, in case
> that specific drive has problems with its termination. That means
> physically rearranging drives.
> > How do I know if I got it right? I wish there was a "scsidiag" program 
> > that would say "Your termination sucks, try this; your SCSI IDs have a 
> > conflict, try this..."
> There is no other way than to open the case and have a look, sorry...
> > The thing that confuses me is thus: There are several termination options 
> > for the drive I placed at the end of the SCSI chain (read the Web page I 
> > referred to: http://www.seagate.com/support/disc/scsi/st15150n.html ). I 
> > do not know which ones are  correct. "Terminate power from drive"? 
> > "Terminate power to SCSI bus"? I know nothing of these things.
> Ah, Seagate. They have a jumper to enable termination: that is putting
> 'the plug on the cable'. This 'plug' needs power, and the other jumpers
> specify where this power comes from. 'Term power from drive' uses the
> driv'es power for this. 'Term power to bus' is independant of the
> on-board terminator; it serves to provide termination power to the
> reserved wire in the SCSI cable.

Thank you. Which one should I use though?

> But, there is something else you need to make sure.
> The error messages you describe _may_ indicate that the filesystems you
> created are larger than the actual drive. This can happen when
> partitioning with some (older?) versions of mac-fdisk (aka pdisk).

I seriously doubt this. This is on a fresh install of Woody (Debian 3.0).

Everyone keeps saying that I have problems with the filesystems. I've 
re-created the filesystems a billion times. I doubt that is it...

Do you know which versions of mac-fdisk had these problems?

> Try using badblocks to verify the drives are OK. Or try using 'dd' to
> read the entire drive (something like dd if=/dev/sd<x> of=/dev/null
> bs=512 count=<number of blocks>).
> If this is your problem, you need to specify the correct drive size when
> creating a partition map with mac-fdisk.
> Cheers
> Michel
> -------------------------------------------------------------------------
> Michel Lanners                 |  " Read Philosophy.  Study Art.
> 23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
> L-1710 Luxembourg              |
> email   mlan@cpu.lu            |
> http://www.cpu.lu/~mlan        |                     Learn Always. "

J e s s i c a    L e a h    B l a n k

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