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SCSI FAQ Questions
Q1. What is a good on-line reference for lots of SCSI topics
and FAQs?
Q2. What default SCSI identification settings does Solaris
expect during installation?
Q3. I see SCSI parity error messages, what should I do?
Q4. What can cause an assortment of unexpected SCSI warnings
like "command timeout" or "SCSI transport failure"?
Q5. I have the latest fast SCSI disk (or other SCSI device),
why do I see information messages telling me that the SCSI
bus controller has negotiated a slower data rate? What can
be done?
Q6. It appears that the SCSI controller can't "see"
my SCSI device, how can I check for sure?
Q7. Does my Themis computer card have a "wide"
SCSI bus, or "narrow"?
Q8. Can I attach a narrow SCSI device to a Themis computer
card or system?
Q9a. My system is not working right with an IBM SCSI disk
drive attached, any ideas?
Q9b. My system is not working right with a Seagate Cheetah
SCSI disk drive attached, any ideas?
Q10. Why can't my Themis USPIIe card "see" the
disk drive attached via P2 paddle adapter?
Q11. Many of the answers in this section mention SCSI cabling
and termination, but what are some other items to consider?
SCSI Questions and Answers (for Appendix information
see link at bottom of page)
Q1. What is a good on-line reference
for lots of SCSI topics and FAQs?
A1. http://scsifaq.paralan.com (Reference used with
permission.)
Q2. What default SCSI identification
settings does Solaris expect during installation?
A2. Primary (boot) hard disk should be ID 0, CD-ROM
should be ID 6, avoid using ID 7 since that's normally the
SCSI host controller ID. Other devices can use IDs 1 through
5.
Q3. I see SCSI parity error messages,
what should I do?
A3. Verify proper SCSI bus termination and proper SCSI
cable length. Also, make sure there aren't too many devices
on the SCSI bus. For details refer to Appendix A, sections
A1.3, A1.4, and A1.5.
Q4. What can cause an assortment
of unexpected SCSI warnings like "command timeout"
or "SCSI transport failure"?
A4. Out-of-spec SCSI cables can cause these errors,
and so can improper bus termination. Intermittent loss of
power (i.e. - power connector integrity) to the SCSI device
is another cause. For details refer to Appendix A, sections
A1.2, A1.3, A1.4, A1.5, and A1.7.
Q5. I have the latest fast SCSI disk
(or other SCSI device), why do I see information messages
telling me that the SCSI bus controller has negotiated a slower
data rate? What can be done?
A5. There could be a variety of reasons. A) The SCSI
controller chip on the host computer may not be as new as
your SCSI disk; for instance a new LVD device installed on
an older SE bus. B) Make sure SCSI bus termination matches
the capability of the host SCSI controller. C) Make sure you
have high-quality SCSI cabling. For details refer to Appendix
A, sections A1.3, A1.4, and A1.5.
Q6. It appears that the SCSI controller
can't "see" my SCSI device, how can I check for
sure?
A6. Use the OBP command "probe-scsi-all".
If your device is not listed then check cabling, bus termination,
and power connectors. For details refer to Appendix A, section
A1.6. Sections A1.3, A1.4, and A1.5 may also apply.
Q7. Does my Themis computer card
have a "wide" SCSI bus, or "narrow"?
A7. Probably wide. Themis products introduced since
1998 have two wide SCSI buses. One way to know for sure is
to check the signal count. 50 wires indicate a narrow SCSI
bus, 68 wires mean a wide SCSI bus. (Of course wide and narrow
are logical descriptions, not physical.) For details refer
to Appendix A, section A1.2.
Q8. Can I attach a narrow SCSI device
to a Themis computer card or system?
A8. Yes. For details refer to Appendix A, sections
A1.2 and A1.3.
Q9a. My system is not working right
with an IBM SCSI disk drive attached, any ideas?
A9a. This is usually cured by placing a jumper on DIS
TI SY. Refer to Appendix A, section A1.1.
Q9b. My system is not working right
with a Seagate Cheetah SCSI disk drive attached, any ideas?
A9b. This is often cured by placing a jumper on Force
Single Ended. Refer to Appendix A, section A1.3. (Note: This
is not necessary if you are sure every SCSI device on your
system is LVD capable - including the host SCSI controller
- and your SCSI bus is running in LVD mode.)
Q10. Why can't my Themis USPIIe
card "see" the disk drive attached via P2 paddle
adapter?
A10. The USPIIe family of cards utilize an LVD SCSI
controller. If you are trying to attach an SE device then
you should install jumper JP1801 to force the host SCSI
controller into SE mode. In fact, this is required if you
are using the 3-row P2 transition paddle adapter to make
connection with the SCSI device.
Q11. Many of the answers in this
section mention SCSI cabling and termination, but what are
some other items to consider?
A11. Check for damaged jumpers that are used to specify
SCSI identification or to enable/disable SCSI device features,
also make absolutely sure the jumpers are the correct size
- 2mm and 0.10" are visually similar but are not compatible;
refer to photos in the Appendix. Check power connectors, make
sure the metal to metal connections are not loose. Check for
short circuits between system chassis and SCSI cable caused
by small breaks in the insulation. Try to test the SCSI device
on another "known good" system if one is available.
Once in a while the SCSI device itself has a malfunction.
Refer to Appendix A, section A1.7.
To download Themis
Board and System FAQ Questions, Answers and Appendix A-B information,
please click here.
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