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From: teroach!stan@phx.mcd.mot.com (Stan Fisher)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A2091 + 2 SCSI drives
Keywords: In article <90216.004446JKT100@psuvm.psu.edu> JKT100@psuvm.psu.edu (JKT) writes:
Message-ID: <13339@mcdphx.phx.mcd.mot.com>
Date: 4 Aug 90 23:50:22 GMT
References: <90216.004446JKT100@psuvm.psu.edu>
Sender: listen@mcdphx.phx.mcd.mot.com
Reply-To: teroach!stan@phx.mcd.mot.com (Stan Fisher)
Organization: Motorola Microcomputer Group
Lines: 30
Summary:

>a 105S) to my 2091.  When I connect it and power up, though, my 2000
>only recognizes the 105S.  Both hard drives work fine when connected
>independently, and neithe fried when I connected them up together, so
>I don't think the cable is bad.  I did take the terminator packs out
>of my 40S and put them in the 105S as the 2091 manual said I should.
>I also changed jumper 5, option 1 on the 2091 to on, so the controller

                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>would recognize more than one SCSI drive.  Is there anything I missed?
>I did not get a manual with the 105S (bought second-hand) so if it

First of all, jumper 5.1 is NOT so the 2091 can recognize multiple drives,
it's to allow multiple logical units to be recognized at EACH physical
SCSI address.  With the Jumper in the off position the controller expects 
a maximum of ONE SCSI device at each of the 7 available addresses (0-6).
With it on, it will attempt to address up to 8 (0-7) logical units (LUNs)
at each of the 7 available SCSI addresses.  The device at a given address
would need to be a controller capable of decoding the LUN addresses and be
connected to multiple drives that would all be at address x LUN x allowing
up to 56 drives on the 2091.  Your configuration however has each of the
two drives as separate PHYSICALLY addressed devices (or at least they
should be) and this jumper would have no effect.  You need to be sure that
each drive is strapped for a different SCSI address (on the drive itself)
to have them both on the 2091 at the same time.  Since you say either one
works alone but the two don't work together, I suspect they are at the same
address.

  Stan Fisher -  stan@teroach.phx.mcd.mot.com  -  asuvax!mcdphx!teroach!stan
  Motorola Microcomputer Division, Tempe, Arizona   -   Voice (602) 438-3228
  Call our User Group BBS "M.E.C.C.A." running SkyLine 1.31 @ (602) 893-0804