Strange termination problem with Adaptec AHA 1540/1542C

Strange termination problem with Adaptec AHA 1540/1542C

Post by Leonard Sitong » Thu, 18 Aug 1994 06:05:34



This is a question about the 1540/1542 setup control for enabling termination.

I've been trying to run Solaris 2.4 EA2 on a 486DX2/66.

I have three internal SCSI devices and one external one (the external
device is an 8mm tape drive).

If I use the built-in setup interface to
disable termination, which I should do since I have devices on both ends
of the board, bootup hangs.  If I enable termination, it boots up.  Is this
a hardware problem with my particular board?

In either case, the "verify disk" operation works all the way through on a disk.

Once the system boots up, with termination enabled, I can basically access all
the devices, including the 8mm tape, but I frequently get disk errors and
tape errors, suggesting a termination problem.

Thank you very much for your time and knowledge.

---
--Leonard E. Sitongia           HAO Sun Unix System Manager

High Altitude Observatory       P.O. Box 3000 Boulder CO 80307  USA

 
 
 

Strange termination problem with Adaptec AHA 1540/1542C

Post by Paul Southwor » Thu, 18 Aug 1994 06:31:57




>This is a question about the 1540/1542 setup control for enabling termination.

>I've been trying to run Solaris 2.4 EA2 on a 486DX2/66.

Why you posted this to comp.os.386bsd.questions I cannot fathom.  However,
support for Solaris 2.4/Early Access releases is available via email from
Pencom, the organization responsible for troubleshooting and bug-reporting
the EA[12] releases of Solaris 2.4/x86.  Send your bug reports to

If you're having purely hardware problems, they may or may not be able
to assist you (in which case comp.os.386bsd.questions and comp.os.linux
should still be reserved for questions about those operating systems).

--
Paul Southworth
CICNet Systems Support


 
 
 

Strange termination problem with Adaptec AHA 1540/1542C

Post by Willard F. Daws » Thu, 18 Aug 1994 10:27:11





>>This is a question about the 1540/1542 setup control for enabling termination.

>>I've been trying to run Solaris 2.4 EA2 on a 486DX2/66.
>Why you posted this to comp.os.386bsd.questions I cannot fathom.

Followups suitably redirected.

>However,
>support for Solaris 2.4/Early Access releases is available via email from
>Pencom, the organization responsible for troubleshooting and bug-reporting
>the EA[12] releases of Solaris 2.4/x86.  Send your bug reports to


A more worthless support organization you'll never find.  Indeed, if Sun
chooses them again, I'll have to re-think *ever* attending their miserable
developer's conference, again...
 
 
 

Strange termination problem with Adaptec AHA 1540/1542C

Post by Matthew Dill » Fri, 19 Aug 1994 12:38:30



::This is a question about the 1540/1542 setup control for enabling termination.
::
::I've been trying to run Solaris 2.4 EA2 on a 486DX2/66.
::
::I have three internal SCSI devices and one external one (the external
::device is an 8mm tape drive).
::
::If I use the built-in setup interface to
::disable termination, which I should do since I have devices on both ends
::of the board, bootup hangs.  If I enable termination, it boots up.  Is this
::a hardware problem with my particular board?
::
::In either case, the "verify disk" operation works all the way through on a disk.
::
::Once the system boots up, with termination enabled, I can basically access all
:::the devices, including the 8mm tape, but I frequently get disk errors and
::tape errors, suggesting a termination problem.
::
::Thank you very much for your time and knowledge.
::
::---
::--Leonard E. Sitongia           HAO Sun Unix System Manager

::High Altitude Observatory       P.O. Box 3000 Boulder CO 80307  USA

    If you have internal SCSI devices *AND* an external SCSI device, the
    termination on the controller should be disabled.

    The last internal SCSI device in the chain should be terminated... usually
    through termination resistors on the device itself.  Other internal
    SCSI devices should NOT be terminated.

    The external SCSI device will generally have two SCSI ports to allow the
    chaining of additional devices.  You either open up your external device
    and install termination resistors as appropriate, or you plug in a
    termination block to the second SCSI port.

    One common mistake is for people to plug in termination blocks without
    providing termination power to the SCSI bus.  The result is that the
    termination block hurts more then it helps.  You need to set ONE of
    the SCSI devices up to provide termination power (usually a jumper).
    It is generally a good idea to have whoever supplies termination power
    be as close to the termination block as possible.  (Frankly, the
    termination blocks ought to have capacitors on the termination power,
    but most of them are made as cheaply as possible).

    Many people recommend having the external device supply the termination
    power.  Even more people recommend that you NOT use a termination block
    and instead install termination resistors in the last external device
    in the chain.  The reason for this is that many SCSI devices leave out
    a critical diode that prevents a powered down device from shorting out
    termination power.

    In summary:

        * The last internal device and last external device is terminated.
          i.e. the two ends of the bus must be terminated.  Devices in the
          middle of the bus are generally not terminated.

        * If there are no external devices you can avoid the use of a
          termination block by enabling termination on your controller,
          which is usually a feature of the controller.

        * If there are no internal devices but there are external devices,
          you normally enable termination on the controller for the
          same reason.

        * watch out if you use termination blocks: some device (or the
          controller) must provide termination *power* to power the
          termination block.  If nobody is providing termination power,
          the termination block may make matters even worse.

                                        -Matt

--


    1005 Apollo Way             ham: KC6LVW (no mail drop)
    Incline Village, NV. 89451  Obvious Implementations Corporation
    USA                         Sandel-Avery Engineering
    [always include a portion of the original email in any response!]

 
 
 

1. Adaptec AHA-1540 Problems.

Hello,
  I'm not a completely new Linux user, but I'm more use to HP-UNIX.  I
have an AMD K6-3 450 256M RAM Box with an adaptec AHA-1540.  In my old
computer, the SUSE 5.3 install would see the scsi card.  When I moved it
to the new box, the install no longer sees the card but both NT and
WIN95 see it.  I have a feeling that I need to change the PNP settings
on the AHA card.  Is there anyway that I can force Linux to use certain
addresses for the card instead of changing the address?

Thanks
Bill


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