[NTLUG:Discuss] SCSI problems - (Was: aic7xxx: infinite...)

Steve Baker sjbaker1 at airmail.net
Tue May 2 12:19:45 CDT 2000


Kevin Brannen wrote:

> > I have been using an adaptec AHA152x to drive my scanner for over
> > a year now - with no problems.  I was given the chance to buy a
> > completely unused (if a little old) HP6020 CD writer (it's the
> > same device as the Philips 2600) - since I had a spare port on
> > the SCSI card, I jumped at the chance.
> >
> ...
> 
> Eeek!  You're really having a bad day here. :-)

Well, it was only $15 - so it sounded like a good deal. Of course
with the amount of time I've spent messing with it, I'm probably
saving less than minimum wage.  <sigh>

> > >From the list of suggestions for typical sources of SCSI
> > problems:
> >
> > ID SETTINGS:
> >
> >   It's ID is 4 - the scanner *was* 6 - but that's disconnected
> >   now "just to be sure".
> 
> In theory, it really shouldn't matter.  However, when I added my
> Yamaha CDRW, I did have problems too.  The Yamaha folks said that
> their device liked ID 3 or 5 better than the others (preferablly 3).
> The support guy didn't know why, but that was what the engineers had
> told him.  So I moved my tape from 3 to 6, and the CDRW from 4 to 3
> and all has been well since.  I know that sounds like voodoo, and I
> consider it to be so, but maybe yours has a similiar preference.  Try
> perusing the HP web site and see if you can turn anything up.

Yes - that does sound like voodoo. It came jumpered to ID==4 - and I
didn't change it - so I presume that if it has a preference, that
would be what the factory would have set it to.


> > TERMINATION:

> Yes, if using internal & external, each must have termination.  Also,
> be sure your card is set to NOT terminate either.  I don't know about
> the 1520 series, but I used to have a 1542C that had that option on
> the card.

The card seems to be devoid of jumpers and switches - so if it's
configurable, the driver would have to do it...and it doesn't
AFAIK.
 
> > CABLES:

> I've found that either they're made well or they're not; and if not,
> then you get intermittent problems.  I had one that worked with 2
> devices but not 3; hence, there must have been bad connectors.  The
> only way I know to troubleshoot this is to have others you can swap in
> and test (but that gets a bit expensive).

The problem with all of these theories is that the contraption works
*PERFECTLY* as a CD reader.  Bad cables/termination/scsi-addressing
would surely show up as a general flakiness in reading? 

> OK, I was thinking of adding HDs when I wrote that.  No master/slave
> thing.  Also, I've never had "vendor incompatabilities" with SCSI like
> with IDE.  And the limit of devices per controller is a higher too.
> :-)

Sure.  SCSI is a pretty good thing for its age. Bear in mind that
IDE was invented to shrink the cost of SCSI back when hard drives
were still something of a novelty and a SCSI interface would set
you back a couple of hundred bucks.  Now that the SCSI interface
is one chip - and the IDE interface is also one chip - it becomes
pretty irrelevent which you use from a cost perspective.

> I've also seen a few controllers that are "almost SCSI", though I
> suspect that's probably not your problem.

Yep - the ones that come with the nastier CD-ROM drives are typically
set up like that.  But the Adaptec is a stand-alone card.

>  However, my 1542C is just
> sitting on the shelf.  I'll offer it to you for testing purposes if
> you'd like (I will want it back. :-)  Email me if you want to do that.

Thanks - I'll let you know if I run out of all other possibilities.

However, since I can reproducably read the table of contents from
a CD using:

   cdrecord -v device=scsi2_cd dev=0,4,0 -toc

...and reliably lock the machine up using:

   cdrecord -v  dev=0,4,0 -toc

...(which allows it to pick it's own driver)...I have to think this
is a driver bug.  The scsi2_cd driver cannot write to the drive
though.

-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjbaker1 at airmail.net (home)  http://www.woodsoup.org/~sbaker
sjbaker at hti.com      (work)




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