In a message of  Peter Deane (3:711/476) wrote to
Kevin Marchant:

 KM>> I need some help with a problem i have with my CD Rom, I have an
 KM>> amiga 2000 with 6 meg of memory and a "Mashita quad spin
CD Rom" The
 KM>> problem is when i access the cd, either through directory opus or
 KM>> shell or through my BBS system it keeps locking up and to free it up
 KM>> i have to turn the cd off and it works again for a few min/secs and
 KM>> locks up again, when it locks up it locks the whole system,

 PD> Hmmm, that sounds remarkably familiar.  I haven't tested this, but the
 PD> advice I have heard is to make your CD the LOWEST POSSIBLE SCSI ID
 PD> unit on the chain.  How many hard drives do you have?  If only one,
 PD> then move the jumpers around so it's ID is up there about 4-6 or so,
 PD> and configure the CD to be 0 or 1 (say).

I cannot see any harm in changing the ID jumpers, but it should make no
difference.  What I have found sometimes makes a difference is where in the
SCSI chain the CDRom is.  Several units have NO switch for temination and
do not have resistor packs (at least none that are accessable).  These seem
to work best if last on the SCSI chain.

 PD> Termination on my old (ex) NEC CD was simply achieved by flicking a
 PD> dipswitch on the back of the CD.  The terminators were there, just a
 PD> switch to make them active or not.  Terminators should be present on
 PD> the FIRST and LAST devices on the SCSI chain.  If you have only one
 PD> Hard Drive and the CD, there should be terminators on BOTH units.

NO !!! You've got it wrong.  While the theory says you need terminators on
both ends of the SCSI chain, the first device on the chain is the
CONTROLLER CARD.  So the only device you "should" terminate is
the last device since almost every SCSI controller has terminators built
in.

 PD> However I found it made not one iota of difference where that
 PD> terminator dipswitch was, and it'd still lockup all the same!  I no
 PD> longer have the CD, unfortunately :-(

Yep, frequently the theory is not what will work.  You must experiment and
find what will work for you and then leave it there.

Different controllers will behave differently with the same device.  What
SCSI card do you have?  

Also what CD Filesystem are you using?  The one I have found is the most
reliable and most compatible with the largest number of controllers and
drives is CDFilesystem V1.15  This is PD as well, which makes things even
nicer.

As an example of weird scsi behaviour, I am running 2 SCSI-2 drives and a
Pioneer DRM 602 6stacker on the SCSI controller of the WarpEngine.

I used to have the HDs inside the A4000 case and in this config I could not
have the CD connected if it was not powered on.  Also, I had to leave the
external SCSI port UN-terminated or it refused to boot.

I now have the HDs in an external case and the CD was locking up (similiar
to yours) until I switched the termination OFF.  Trial and error :-\

Cheers,

Arnie

arnie{at}euphoria.bay.net.au
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