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Conference mvblab::alphaserver_4100

Title:AlphaServer 4100
Moderator:MOVMON::DAVISS
Created:Tue Apr 16 1996
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:648
Total number of notes:3158

551.0. "Single-ended SCSI & the farthest shelf" by HGOVC::NANDAN () Thu Mar 27 1997 06:11

    
    I am configuring two 4100s (not clustered) in a single H9A10-ED. 
    This means that I can have up to 6 StorageWorks shelves on top of 
    the two system drawers.
    
    Suppose I have a KZPAA or KZPDA (both single-ended SCSI) in the 
    lower system drawer, how far can the BN21N-02 or BN21K-02, 
    respectively, go. Which would be the farthest shelf that the cable 
    can reach.
    
    Below is a side view of the 4100, with the numbering of storage 
    shelves and system drawers as given in the SOC.
    
    +---+     +---+
    | 1 |     | 3 |
    +---+     +---+
    +---+     +---+
    | 2 |     | 4 |
    +---+     +---+
    +---+     +---+
    | 5 |     | 6 |
    +---+     +---+
    +---------------+
    | System Drawer |
    | 1             |
    +---------------+
    +---------------+
    | System Drawer |
    | 2             |
    +---------------+
    
    Can someone please let me know this information.
    
    Thanks in advance.
    
    Nandan
T.RTitleUserPersonal
Name		DateLines
551.1Manufacturing will substitite of too shortVYGER::HENDERSONLThu Mar 27 1997 06:268
    You do not need to worry about the length of cables, manufacturing will
    replace the cable with a longer one if it is too short. Only need to
    think about the cable length of you are adding to an existing installed
    system, then you can measure it for yourself and order accordingly.
    
    
    
    Les
551.2The -02 means the cable is 2 meters longKOKY::PEREZThu Mar 27 1997 14:247
    Some additional info. The -02 means that it is 2 meters long, so you
    have a cable that is 2*39.37 inches = 78.74 inches or 6.56 feet long.
    
    The -0X on a cable is the lenght on meters.
    
    Ozzie Perez
551.3Thanks...but what I meant is...HGOVC::NANDANFri Mar 28 1997 05:0813
     
    Les & Ozzie,
    
    Thanks for your response. I need to explain what I meant.
    
    If the distance from the KZPDA/KZPSA to the farthest box exceeds the
    SCSI limit of 3 metres, then I would need to use a KZPSA & DWZZB.
    
    Can you elaborate in the light of this please.
    
    Thanks in advance.
    
    Nandan
551.4this what you're looking for?SWAM1::SOTO_RUFri Mar 28 1997 12:2326
    Each BA36R requires 7".
    Each system drawer requires 11.8" (make it 12 for calculations but the
    SOC has 11.8" as the exterior height dimension for the drawer)
    The H9A10 holds six BA36Rs but they're 3 front, 3 rear.
    The cabinet is 38.2 inches deep (again from the SOC).
    
    So your longest run will be from about half-way up the lowest system
    drawer in the rear to the top shelf all the way to the front.
    
    So the math would be (approximately):
    
    38.2 + (3X7) + 12 + 6 = 77.2 inches.
    
    It'll probably be greater than this since you must accomodate cable
    bend requirements.
    
    If the BN/BK 2-meter cables are 79.4 inches, it'll be real tight.
    
    There's a BN21K-03 (3 meters) which should give you plently of 'play'
    but don't know if it's qualified with KZPDA.
    
    BTW, there may be excellent reasons for the KZPSA/DWZZB combination.
    Cost isn't one of them, however.
    
    regards,
    Ruben
551.5POBOXB::BAKFri Mar 28 1997 16:107
Hi,

I set the cabling rules. A 2m cable works with any shelf/drawer position in the
H9A10-EB/ED cab. It may be tight but it can be built. Your CANNOT use a 3m cable
(and run at Fast SCSI speeds).

	Dennis
551.6Thank you!HGOVC::NANDANSat Mar 29 1997 21:5515
    
    Ruben,
    
    Thanks for your response & all the information.
    
    Dennis,
    
    Well, as in the case of my earlier notes, you have the final word.
    Thank you.
    
    Nandan.
    
    P.S : Dennis, do you think you could put this info into the next
    version of the SOC, to help someone else having a similar config
    question ?
551.7POBOXB::BAKMon Mar 31 1997 10:167
Hi,

Cabling rules will be changing in the not too distant future as we introduce
UltraSCSI. Significant cable length for single ended solutions will be allowed.
Stay tuned for details.

	Dennis
551.8Will stay tuned !HGOVC::NANDANTue Apr 01 1997 21:0912
    
    Dennis,
    
    By "not too distant future" I assume you mean somewhere towards the end
    of Q1FY98.
    
    I do hope your guidelines, at the appropriate time, will make the
    transitioning to UltraSCSI easy.
    
    Thanks,
    
    Nandan