SCSI Configuration Troubleshooting


When you are installing a chain of devices on a single SCSI bus, the installation can get complicated very quickly. If you have a problem during installation, you should check the following first:

  • Make sure you are using the latest BIOS from your motherboard manufacturer. Some have had problems with their PCI bus slots not working properly.

  • Make sure that all SCSI devices attached to the bus are powered on.

  • Make sure that all SCSI cables and power cables are properly connected. Try removing and reseating all the connectors to be sure.

  • Check that the host adapter and each device on each SCSI bus channel has a unique SCSI ID setting.

  • Make sure the SCSI bus is terminated properly. Remember that there should be only two terminators on the bus, one at each end. All other terminations should be removed or disabled.

  • If your system BIOS setup has settings for controlling PCI bus configuration, make sure the PCI slot that contains the SCSI adapter is configured for an available interrupt. If your system is PnP, use the Windows Device Manager to check and possibly change the resource configuration.

  • If you have a SCSI hard disk installed and your system will not boot from the SCSI drive, there can be several causes for this problem. Note that if both SCSI and non-SCSI disk drives are installed in your computer, in almost all cases, the non-SCSI drive is the boot device. If you want to boot from a SCSI drive, check the boot sequence configuration in your BIOS. If your system allows it, change the boot sequence to allow SCSI devices to boot first. If your system does not allow this type of changes, try removing the non-SCSI drives from your system.

If the system has only SCSI disk drives and still doesn't boot, check the following:

  • Be sure your computer's BIOS Setup drive configuration is set to No Drives Installed. The PC BIOS supports only ATA (also called IDE) drives; if you set this to No Drives, the system will then try to boot from another device, such as SCSI.

  • Make sure the drive is partitioned and that a primary partition exists. Use the Windows Disk Management tool in Windows 2000/XP/Server 2003 to check.

  • Make sure the boot partition of the boot hard disk is set to active. This can be checked or changed with the Disk Management program.

  • As a last resort, you can try backing up all data on the SCSI hard disk and then perform a low-level format with the Format utility that is built in to or included with the host adapter.

Here are some tips for getting your setup to function quickly and efficiently:

  • Add one device at a time Rather than plugging numerous peripherals into a single SCSI card and then trying to configure them at the same time, you should start by installing the host adapter and a single hard disk. Then you can continue installing devices one at a time, checking to ensure that everything works before moving on.

  • Keep good documentation When you add a SCSI peripheral, write down the SCSI ID address and any other switch and jumper settings, such as SCSI Parity, Terminator Power, and Delayed or Remote Start. For the host adapter, record the BIOS addresses, interrupt, DMA channel, and I/O Port addresses used by the adapter, and any other jumper or configuration settings (such as termination) that might be important to know later. Note that some of the configuration tasks performed on the latest SCSI host adapters are performed through the SCSI configuration program that is built in to the SCSI BIOS.

  • Use proper termination Each end of the bus must be terminated, preferably with active or FPT terminators. With Fast SCSI-2 and newer devices, you must use active terminators rather than the cheaper passive types. If you have only internal or external devices on the bus, the host adapter and last device on the chain should be terminated. If you have external and internal devices on the chain, you generally terminate the first and last of these devices, but not the SCSI host adapter (which is in the middle of the bus).

  • Use high-quality shielded SCSI cables You need to be sure your cable connectors match your devices. You should use high-quality shielded cables, and observe the SCSI bus-length limitations. You should also use cables designed for SCSI use, and, if possible, stick to the same brand of cable throughout a single SCSI bus. Different brands of cables have different impedance values; this situation sometimes causes problems, especially in long or high-speed SCSI implementations.

Following these simple tips will help minimize problems and help ensure a trouble-free SCSI installation.




Upgrading and Repairing Servers
Upgrading and Repairing Servers
ISBN: 078972815X
EAN: 2147483647
Year: 2006
Pages: 240

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