[comp.unix.i386] Trouble in stalling ISC 2.2 with multiple SCSI drives.

pdg@chinet.chi.il.us (Paul Guthrie) (06/29/90)

Well, I was trying to install Interactive Unix 2.2 on my system,
and ran into a problem.  I hooked up a new SCSI drive as the boot
drive (SCSI ID 0) and had my old drive as ID 1 (tape is ID 2). 
The cable I am using is a 4 connector SCSI 50 pin internal 
cable going from the host adaptor to drive 0 to drive 1 which
is properly terminated.  The tape is on another (external) bus.
Anyway, the host adaptor (Adaptec 1542A) hangs on one of the first
disk accesses.  I tried hooking up the new drive as the only drive
(changing terminations) and it installed OK, but after that and 
rebuilding the kernel to make sure, on going back to the two
drive configuration, I still get hangs.  Anyway, to make
a long story short, can you use a 4 connector SCSI cable with
3 devices (host adaptor, 2 disks), leaving one of the middle
connections loose.  I know this works for ST506, ESDI and floppies,
but SCSI has it's own specs.  Any other suggestions?  Also could there
be some sort of conflict between the drives?  I am running a 
Fujitsu M2263SA as drive 0 and a HP 9754XS as drive 1.  I also
have parity checking disabled.  Would enabling this help?
-- 
Paul Guthrie
chinet!nsacray!paul or pdg@balr.com or attmail!balr!pdg

jgd@rsiatl.UUCP (John G. DeArmond) (07/03/90)

pdg@chinet.chi.il.us (Paul Guthrie) writes:

>Well, I was trying to install Interactive Unix 2.2 on my system,
>and ran into a problem.  I hooked up a new SCSI drive as the boot
>drive (SCSI ID 0) and had my old drive as ID 1 (tape is ID 2). 
>The cable I am using is a 4 connector SCSI 50 pin internal 
>cable going from the host adaptor to drive 0 to drive 1 which
>is properly terminated.  The tape is on another (external) bus.
>Anyway, the host adaptor (Adaptec 1542A) hangs on one of the first
>disk accesses.  

I hate to ask an obvious question but have you determined that your
terminators are configured correctly?  Specifically, terminators 
installed on each physical end of the bus and NONE anywhere else?
While you can be loosy-goosy with terminators on ST-506 drives, an
extra terminator will absolutely kill the bus.

If the answer to the above question is "I'm not sure", then be sure
to check the pico-fuse on the Adaptec board.  This fuse protects the
termination supply and generally gets zapped when extra terminators 
are in place.

John

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paul@cs.utexas.edu (Supoj Sutanthavibul) (07/03/90)

In article <1990Jun29.150947.19939@chinet.chi.il.us> pdg@chinet.chi.il.us (Paul Guthrie) writes:
>...
>Anyway, the host adaptor (Adaptec 1542A) hangs on one of the first
>disk accesses.  I tried hooking up the new drive as the only drive
>(changing terminations) and it installed OK, but after that and 
>... have parity checking disabled.  Would enabling this help?

1)  Make sure you close the dip switch #7 on M2263SA.  It should be
    the switch for synchronous mode transfer.

2)  Remove the terminating resistors from the drive in the middle of
    the SCSI bus (in this case it's the M2263SA).  If you've tried this
    already, please ignore it.

3)  The parity checking doesn't seem to matter much.

4)  You can have any number of open connections in the middle of the bus.

supoj

mbl@unlisys.UUCP (Max Bluecher) (07/06/90)

pdg@chinet.chi.il.us (Paul Guthrie) writes:


>I hooked up a new SCSI drive as the boot
>drive (SCSI ID 0) and had my old drive as ID 1 (tape is ID 2). 
>The cable I am using is a 4 connector SCSI 50 pin internal 
>cable going from the host adaptor to drive 0 to drive 1 which
>is properly terminated.  The tape is on another (external) bus.

Maybe you have to remove the terminators from the adaptec itself, cause
the streamer on the external bus is the other physical end of your scsi-chain.

>I also have parity checking disabled.  Would enabling this help?

I think it won't help in this case, but in general parity-checking is a 
valuable feature of the scsi-definition and should allways be enabled.

Max
-- 
				Max Bluecher
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