Newsgroups: comp.sys.atari.st.tech
Path: utzoo!utgpu!cunews!bnrgate!bcars223!fortinp
From: fortinp@bcars223.bnr.ca (Pierre Fortin)
Subject: Re: HD Help Needed
Message-ID: <1990Sep11.081759.589@bnrgate.bnr.ca>
Sender: news@bnrgate.bnr.ca (USENET News System)
Organization: Bell-Northern Research, Ltd. Ottawa Ontario CANADA
References: <1990Jul31.165603.20869@msuinfo.cl.msu.edu> <1407@wet.UUCP> <12320@ists.ists.ca>
Date: Tue, 11 Sep 90 08:17:59 GMT

In article <12320@ists.ists.ca>, os9paul@gkcl.ists.ca (Paul Good) writes:
> Is it possible to connect more than one SCSI device to the SH204 host adapter?

No.  But, you should be able to use TWO SH204 host adapters (make me an offer
for my old one).  The DIP switches on the HA should be your clue; the Atari HA
is useless for multiple devices.  Note also that the Atari HDX software is 
useless for anything but Dev0/LUN0.

I have 3 HDs connected to two Adaptec 4000A controllers to an ICD HA, and 
run ICD software.  With no problems...

> 
> I have tried the following, but have not been able to get the computer to
> recognize more than one drive at a time:
> 
> Setup one:
> 
> SH204-----Seagate 251N-----Adaptec4000A=====Seagate 251 (LUN 0)
>   
> Setup two:
> 
> SH204-----Seagate 251N-----Seagate 225N
> 
> Perhaps I am mistaken about some aspect of how SCSI works, but I thought
> that I should be able to use setup one and have the 251N as DEV 0, LUN 0
> and the Adaptec/251 as DEV 1, LUN 0.

You'd be OK here if it wasn't for the restrictive host adapter...
> 
> Has anyone been able to connect more than one SCSI device or intermix
> imbedded drives with Adaptec controllers?  Is this possible with the
> SH204 host adapter or must I buy a different flavor?  Any ideas about
> wht I may be doing wrong?

Yes!  No, buy another HA.  Yes, you are making an invalid assumption about
"Power without the Price".
> 
> TECH INFO:  The SH204 host adapter has the ADE PAL installed.  Hard drive
> software is Supra 2.72; TOS is 1.4.

TECH TIP:  If you want to dedicate one drive for testing and one for 
production work, try this trick:  

 
        Cont-0             DPDT-switch             Cont-1

                           +---------+
             --------------|O   O   O|-------------
                           |    |    |
                           |    |    |
             --------------|O   O   O|-------------
                           +---------+

Connect the wires to the address selection jumper pins on the controller (the
ones which cause the controller to respond to Dev1 when a jumper is installed).
Then, when the switch shorts out the pins on Cont-1, all is normal.  Flipping
the switch causes both controllers to swap identities (0>1 and 1>0).  Works
great and allows trying different boot programs without risking the need to
go back to diskette if a new boot program doesn't work; just flip the switch
and reboot from the other controller...

> 
> --
> 
> Paul Good   INTERNET: os9paul@gkcl.ists.ca   UUCP: ists!gkcl.ists.ca!os9paul

Enjoy!

Pierre Fortin
fortinp@bnr.ca
