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G4 533 Server SCSI Conflict

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I have a 533 MHz G4 ASIP 6.3 Server running OS 9.1. I have been trying to backup my server using an external SCSI Lacie SDT-11000 tape drive. I am running Retrospect 4.3 Workgroup as the back up software. The G4 sees the tape drive and everything proceeds smoothly until I execute the backup. It copies 1-2 files, then just hangs. I have used this tape drive sucessfully with my older G4 servers (400MHz). The only difference is that in the newer G4 machines there is a different SCSI card with a different external SCSI interface. I bought the new cable but nothing I try can make it work. Apple claims that there is no issue using a SCSI tape drive attched to the external port. Dantz, as you may or may not know, only offers paid support at a very high price. I have never heard of a company that doesn't offer support for it's products. Anyone have any ideas??

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New customers are entitled to 30-days free support. If you have recently purchased your full product (not upgrade), please contact Customer Support for Technical Support options.




That being said, with a lock up on the backup Macintosh, you want to try moving the mouse to see if the ADB bus has locked up as well. If the mouse moves, but the Mac is hung up, it's most likely that your SCSI bus is hung, and you have a SCSI problem. If the mouse doesn't move, that means that the Mac's processor is hung, and you should look at System Software and extensions. More often than not, you will find that the mouse moves and you can force quit the program (at which point the Mac may or may not completely crash).




A SCSI hang can be caused by one or more of the following:


1) a dirty tape drive or bad tape. Clean the drive. Try another tape. If other tapes work, then you just have a tape with a spot that's bad enough to crash your backup.




2) another device on your SCSI bus is interfering with the tape drive's communication. Make sure your SCSI ID numbers are set correctly. Turn off your Mac and the SCSI devices. Disconnect all SCSI devices except for the tape drive.




3) you have a bad cable. Replace the SCSI cable that connects the tape drive to the computer after removing other devices and cables from the SCSI chain.




4) you are missing a terminator or have a bad terminator. The last device and ONLY the last device in your SCSI chain needs to be terminated. Try replacing the terminator if you already have one on the chain.




5) the computer may be having a problem. Install Retrospect on another Macintosh and try the tape drive there as the lone SCSI device.




6) the drive may be defective. If you have implemented all of the preceding steps and get failures on multiple tapes after changing cables, terminators and computers, then the drive, being the only factor that has not changed, is the culprit--send it back to your vendor for repairs.




The steps above are the essential outline of our SCSI troubleshooting here at Dantz. Hands on testing of device issues is really still the best method and even getting SCSI logging information is usually only to confirm empirical testing. Note that concluding something is a bad device is the LAST thing we assume after all other components and variables have been ruled out.




"SCSI voodoo", as they call the nebulous symptoms that can plague a SCSI bus, can often lead one to false assumptions of the cause of problems. It's important that once a variable is tested that it be tested more than once for consistency's sake to rule out dumb luck. For example, SCSI voodoo accounts for why a tape drive may work fine for many months without proper termination but then suddenly fail in some way later. Although customers will often cite that nothing has changed with their SCSI bus configuration in months and that it was all working before, this is really a hallmark inconsistency of SCSI voodoo.




The quickest and most conclusive test for most devices is to test it on more than one computer as the only device on the bus and with a different SCSI cable. If the problems can be reproduced on multiple computers, it's more than likely a hardware problem with the device itself.




Of course there a myriad of other specific issues having to do with a device's own hardware settings like with internal jumper cables, dip switches or internal termination that has to be sorted out with the device's manual and/or vendor or manufacturer of the drive but the kernel of SCSI troubleshooting above is a good general guideline.

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