terminate illiterate
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  1. #1
    Join Date
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    terminate illiterate

    Pardon my ignorance but was stuck with an old IBM N1H 0664 SCSI3 HDD until I figured out the SCSI card I had wouldn't support it. Finally got the right card. The SCSI utility detects it, but Windows doesn't. Figure it's a termination problem.

    Looked up the IBM web page and have the HDD jumpered for termination. So I shouldn't need to add a physical terminator, right? (4 connectors on the cable, adapter LUN7, HDD LUN0 as usual.) But there are other jumpers I can't figure out.

    And there oughtta be a way of terminating the whole thing in the Adaptec utility, right? Or wrong? Am falling all over my face with this thing. The jumper settings are at http://www.storage.ibm.com/hdd/suppo...m/0664mjum.htm at the IBM web site.

    Thx for any assistance with this thing.

    ------------------
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -

  2. #2
    Join Date
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    Manila, Philippines
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    13,269
    Hi ST:TNG. It's been a while... you're going to have to physically terminate the drive. Sorry.
    ? Quantum Physics ? Light travels faster than sound. This is why some people appear bright until you hear them speak.

  3. #3
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    Hi, Toolbox - It has been a while. Now correct me if I'm wrong, but that means I move the device one connector closer to the Adaptec and then add a physical terminator where the hard drive used to be?

    So now my question is whether I need active or passive termination. Which, I guess, tips my hand that I don't really understand the difference.

    And, speaking of ignorance, if a jumper is labeled TERM PWR, as was the schematic you graciously interpreted for me, why doesn't it terminate the HDD the pins are on?

    ------------------
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -

    [This message has been edited by ST:TNG (edited 02-01-2002).]
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -

  4. #4
    Join Date
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    Location
    Memphis Tennessee
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    4,930
    From IBM How To's on SCSI.

    "Termination:
    SCSI systems should have termination at both ends of the cable. Make sure that the controller terminates one end of the cable and that a drive supplies termination at the other end. If a drive doesn't have onboard termination, a terminator should be placed on the last connector of the cable.
    Make sure that there is no extra cable after the terminator at the end.
    Any device attached that is not at the end of the cable must have internal termination disabled.
    For adapters with multiple SCSI ports with differing performance, ALL ports must be correctly terminated.
    For adapters with a common port with both internal and external connections in use, DO NOT enable termination on the controller.
    Narrow (50 pin) devices SHOULD NOT be connected at the end of a wide (68 pin) SCSI cable. A terminator in a 50 pin SCSI device cannot provide the correct termination for the unused data lines.
    Using a 68-50 pin cable converter to connect a 68 pin disk drive to a 50 pin SCSI adapter could cause problems because the 68-50 pin cable converter leaves 18 of the 68 pins on the disk drive without termination."

    I hope to learn from your tiral.


    If I move the device one connector closer to the Adaptec and then add a physical terminator then I need active .... termination.

    Note: Make sure that there is no extra cable after the terminator at the end.
    Any device attached that is not at the end of the cable must have internal termination disabled.


    What kind of cable are you using?



  5. #5
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    Hi, Leoslocks - Thought I read there were only 3 posts (me, Toolbox, me) and almost didn't see your reply. Even E-mailed it to dimarini for help.

    There were two SCSI cables at Fry's, one for $70 and one for $35. Naturally I bought the one for $35.

    On the invoice, it reads:
    Wide, SCSI-III Ribbon Cable, Mini 68 for 3-drives. 4 Conn. 30" TPE/TPO

    Does this help?

    Thx,

    - - - Chris - - -

    ------------------
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -
    If you can't be a good example,
    then you'll just have to be a horrible warning.
    - - - Catherine Aird - - -

  6. #6
    Join Date
    Jun 1999
    Location
    Austin, Texas, USA
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    1,771
    ST:TNG,

    I found the following information on IBM's support website.

    SCSI Bus Terminators

    --------------------

    0664 has no internal SCSI bus terminators. The system is

    responsible for properly terminating the SCSI bus. A

    regulated 110 Ohm terminator is recommended for reliable

    fast operations (ie, transfer speeds greater than 5M

    transfers/sec). Split resistor or regulated terminations

    may be used for systems that do not plan fast data transfers.

    Some of the terminator possibilities for 0664 are listed

    in Figure 6.

    Figure 6 is found on page 13 of the follwing link:
    http://www.storage.ibm.com/hdd/suppo...m/0664-x1h.pdf



    Since they mention 110 ohms for the terminator, to me that means it must be an active terminator. These are available at Fry's or online. You just set the adapter to auto terminate then move the drive one connector from the end and attach an active terminator to the end of the cable and all should be fine.

    I hope this helps.

    Regards,



    ------------------
    Mike
    Mechanical Engineer
    Dell Computer Corporation
    Storage Systems Group
    Mike
    Mechanical Engineer
    Dell Computer Corporation
    Server Development

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