Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!bagate!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: (was RAMSEY) 2nd SCSI controller
Message-ID: <20912@cbmvax.commodore.com>
Date: 24 Apr 91 15:15:49 GMT
References: <1991Apr12.002442.3871@minyos.xx.rmit.oz.au> <1991Apr23.010944.10776@ariel.unm.edu> <20874@cbmvax.commodore.com> <41588@cup.portal.com>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 34

In article <41588@cup.portal.com> FelineGrace@cup.portal.com (Dana B Bourgeois) writes:
>Dave, 

Who, me?  Is this comp.sys.amiga.haynie or something :-)

>I haven't seen anyone ask this before.  Can you run more than one SCSI 
>controller in an Amiga?  If so, is there any special setup to do to make it 
>work?  (over and above the usual stuff)

Not usually.  For kicks, I ran an A3000 set up with A2091, Hardframe, and
internal SCSI drive all going at once.  It ran for over two weeks, basically
until I had to take it down for other purposes.

Generally, two SCSI controllers are completely unrelated -- they use different
device drivers and follow normal autoboot priority conventions to figure out
who actually gets to boot the system.  Of course, if you add two A2091, for
example, you get multiple devices with the same device driver name.  Assuming
the controller software knows about the conventions for this, this isn't a
problem.  From what I recall (software types feel free to correct this), the
unit number in this case is a natural extension to scsi.device.  You normally
get units from 0 through 7, corresponding to the traditional 8 physical SCSI
devices.  The 10's place digit, though, can also range from 0 through 7,
indicating logical unit numbers.  And finally, the 100's digit indicates which
controller to address.  So unit 0 is physical unit 0, LUN 0, on the first 
A2091, unit 100 is physical unit, LUN 0, on the second A2091.  Or something
like that...

>Dana bourgeois @ cup.portal.com


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
      "That's me in the corner, that's me in the spotlight" -R.E.M.