my scsi hard disk doesn't work with my cdrom

[John Davis <davis@bops.com>]

Hello

I need help installing a new scsi hard disk in an old sparcstation 5.
For some reason, I can not get the drive to work properly with the
existing cdrom in the sparcstation.

Here are the facts:

The sparcstation had an older, smaller, slower scsi hard disk which
worked fine with the cdrom.

The new harddisk works, but it causes the cdrom to disconnect from the
scsi bus during large file copies from the cdrom to the hard disk.
That is, 90% of the time when I copy large files from the cdrom to the
hard disk, the copy will fail midway and I will be dumped back to the
shell prompt.  At the shell prompt, it appears as if the cdrom is gone.
However, "mount" shows the cdrom as still mounted.  If I "umount" the
cdrom and then re"mount" it, it appears ok and I use it again for small
file transfers.

The problem exists using Debian Linux or OpenBSD.

I've tried various jumper settings on the cdrom and on the hardisk.
The settings on the old and new harddisks are not identical though.  See
the attached URLs.  

I checked http://docs.sun.com for the settings on the cdrom.  It says
that only the scsi id and termination jumpers should be installed.  (I
added the parity jumper as well.)

Finally, I'm beginning to wonder if the cdrom is bad.  Is there anyway I
can test it?

Relevent links:

The new hard disk:
http://www.storage.ibm.com/techsup/hddtech/dchs/dchsjum.htm

The old hard disk:
http://www.seagate.com/support/disc/specs/scsi/st31200w.html

John Davis