[comp.sys.atari.st.tech] HD Help Needed

os9paul@gkcl.ists.ca (Paul Good) (09/11/90)

Is it possible to connect more than one SCSI device to the SH204 host adapter?

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.

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?

TECH INFO:  The SH204 host adapter has the ADE PAL installed.  Hard drive
software is Supra 2.72; TOS is 1.4.

--

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

fortinp@bcars223.bnr.ca (Pierre Fortin) (09/11/90)

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

csbrod@medusa.informatik.uni-erlangen.de (Claus Brod ) (09/17/90)

os9paul@gkcl.ists.ca (Paul Good) writes:

>Is it possible to connect more than one SCSI device to the SH204 host adapter?

>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.

As far as I know from previous inspections, the SH204 holds DEV 0
selected all the time and never ever releases this selection until
power is switched off. This means that the SH204 host adapter is not
capable of selecting any other SCSI drive than DEV 0. At least, this
is what I have been told. You can, however, put a second MFM drive
of the ST506 type into your SH204 by connecting it to the Adaptec
controller. Using special software (i.e our software 8-) you can
then use the two drives. I don't know if the Supra software supports
two LUNs on a SCSI controller, too.

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Claus Brod, Am Felsenkeller 2,			Things. Take. Time.
D-8772 Marktheidenfeld, West Germany		(Piet Hein)
csbrod@medusa.informatik.uni-erlangen.de
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