Messages in this thread | | | Date | Sun, 22 Jun 1997 10:34:31 -0700 | From | "Leonard N. Zubkoff" <> | Subject | Re: scsi-problem (phase change ?) |
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Date: Sun, 22 Jun 1997 13:05:32 +0200 (MET DST) From: Hauke Johannknecht <ash@ash.ccc.de>
urgl. hmm, how can i describe my scsi-bus ... i will go from one terminator to the other ... first end (inside computer) |--- Quantum LPS with terminators installed (passive ?) ---> ---> IBM DCRS (no way to terminate this one ... <g>) ----> ---> NCR 810 ---> ---> external cable (80cm) ---> ---> external 4-device-box ---> ---> Seagate ST1600N ---> ---> Sanyo CD-ROM ---> ---> HP 6020i ---> ---> end of external box ---> ---> external active terminator ---| makes a total of no more than 2 meters ...
(1) If you run even normal Fast SCSI-2 (10.0 mega-transfers/second) on your SCSI bus, you should have *active* termination at both ends. Some configurations *might* get away with passive termination, but at the first sign of any problems you should immediately move to active termination.
(2) Ultra SCSI (20.0 mega-transfers/second) is even more stringent. If I recall correctly, you are allowed 3 meters cable length only if you have at most 4 devices, and 1.5 meters if you have more. The cables must also be built to much more stringent specifications. This doesn't apply to your configuration since the 53c810 isn't Ultra-capable, but it's here for reference.
With this configuration, I'd suggest it's time for a second SCSI bus.
Leonard
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