Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!uakari.primate.wisc.edu!ames!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!cit-vax!tim
From: tim@cit-vax.Caltech.Edu (Timothy L. Kay)
Newsgroups: comp.periphs
Subject: How many SCSI disks on one ribbon?
Message-ID: <11920@cit-vax.Caltech.Edu>
Date: 16 Sep 89 00:16:53 GMT
Reply-To: tim@cit-vax.UUCP (Timothy L. Kay)
Distribution: usa
Organization: California Institute of Technology
Lines: 22


I am hooking some Newbury drives to an Iris 80GTB, and I am running
into just a bit of trouble.  When I have four 380 MB drives hooked
up, everything works great.  If I hook up a fifth, I am overloading
the bus somehow, I think.  When it boots, I get the message

  unexpected transfer phase: state=4b phase=20
  resetting scsi: hardware error

It seems to happen only when that fifth drive is on the ribbon cable.
I have moved the drives to different connectors on the cable to verify
that there are no bad connectors.  Also, when I am in the five drive
configuration, I can use all five drives, but the bus gets errors
infrequently.

Anybody have any ideas what could be wrong?  Is there a document
that tells me about maximum cable lengths, more information about
termination, etc.?

Thanks in advance,

Tim