SCSI setup.. Termination question.

[Salvador]

I plan on running two scsi internal hdd's and one external scsi zip drive. My controller card is one termination, but I don't know where to put the other termination in the chain because I don't plan on having the external scsi hard drive installed all of the time. I plan to hook it up once in a while if I need it.

Do I have to terminate the scsi chain with the second internal scsi hard drive and then unterminate it when I want to use the external scsi zip drive? Or.. Can I terminate the second internal scsi hard drive and just hook up the external scsi zip drive without touching the terminated internal scsi zip drive? Will it work this way?

TIA,

Sal

 

[zzzz]

assuming this is only with 1 channel terminate only the end parts. e.g the external zip and one of the internal hard disks which is furthest away on the chain.
If the controller has auto termination this will work, otherwise you have to turn it off and on depending on whether you will take the zip drive away.

 

[tlemmon]

Always terminate the first and last physical device on a SCSI chain. So if a hard drive is one end of the cable and the zip drive at the other (external connections count as a continuation of the internal cable) you would want to terminate the hard drive and zip drive. If there were no zip drive then terminate the hard drive and the SCSI card. Remember, the SCSI card is an actual device in the chain. Most Adaptec SCSI cards support auto-termination so you would want to terminate the external device and enable auto-termination in the SCSI cards BIOS. With this setup, if you were to power up the external device (system has to be off first otherwise it could cause a lockup) the card would sense the external device and not terminate itself.

This is how I have my system setup---> I have an external CDRW that I dont use all the time which is terminated. I have 2 SCSI hard drives inside and an internal DVD-ROM drive. I terminate the DVD-ROM drive and have the SCSI card set for auto-termination. When I power up the CDRW the SCSI card sees the CDRW and does not terminate itself.

I hope I havent confused you here. If you have any question, just ask. I will do what I can to help.


-t

 

[bozo1]

tlemmon is exactly correct. Couldn't have said it better myself.

 

[Salvador]

Thank you very much!!

Sal