Just come across this thread, so I'd like to add that I also have a similar problem as well. We have a MSL5026S2 dual tape drive connected to a adaptec 39160 scsi card in a Dell PE 2650 server. The library is connected to the network and can be remotely managed. Everynight for the last one month we have had the tape library completely hanging during backup but not the two tape drives inside, they still perform the backup. Sometimes the unit also hangs during the day without a backup being performed. When it hangs, the event log in Windows 2003 will record a SCSI timeout error for the 39160 card driver. I have tried replacing the SCSI cables, changing the SCSI IDs of devices without success. Have even called HP warranty to replace the controller board two weeks ago without success. Controller board has latest FW 4.23. When it hangs, the LCD screen is also frozen and only a power off and power on switch at the back of the unit will restore it.
After reading your problem above, I will unplug the network cable tonight and see whether the problem goes away.
Rick: Is there any update from the HP engineers about this yet??
PS. We also having problems with jetdirect cards failing on HP4100N printers (four so far). The jetdirect cards are not detected by the printer anymore and have to be replaced with a new one. Only recently happened from about 1-2 months ago. Being a University environment, we do have a lot of virii/worms infections and network scanning happening and that could be the cause of it, since we had similar problems durind the Code Red outbreak with HP4000 jetdirect cards doing memory dumps until a firmware update fixed it.
