Operation Manual

Installing Optional Equipment
● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● A5000/A4000 • Appendix 253
■ Reasons for SCSI errors
A SCSI bus operates stably only if all the connected SCSI devices are operating correctly. If any of the
devices are producing noise, the other devices will also produce errors, and in the worst case, the boot
block of a drive can be destroyed. (All data in that drive will be lost.)
Also, there are cases in which a system on which data appears to have saved may not have actually
saved the data, resulting in data loss.
The following paragraphs will discuss the reasons for such errors, and will provide a sequence for your
troubleshooting.
• Check the SCSI ID
Make sure that there is no conflict between the SCSI ID of each SCSI device including the A5000/
A4000. When shipped from the factory, the A5000/A4000’s SCSI ID is set to 6. We suggest that the
internal hard disk normally be set to 4. Be sure to turn off the power before changing the SCSI ID
setting.
• Check the terminator
As discussed above, check the location where the terminator is attached.
• Check the SCSI cables
Low-quality SCSI cables will almost always create problems. Always use double-shielded cables. It
is also important that the shield be grounded inside the connector. Long SCSI cables frequently
cause problems, so use as short a SCSI cable as possible. Bending or twisting a SCSI cable in a
confined space can cause conductors to break or pins to be broken, so be careful to avoid this.