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Conference ssag::ask_ssag

Title:Ask the Storage Architecture Group
Notice:Check out our web page at http://www-starch.shr.dec.com
Moderator:SSAG::TERZAN
Created:Wed Oct 15 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:6756
Total number of notes:25276

6714.0. "Odd active-termination behavior??" by ROMOIS::FARRAUTO (Sic Semper Tyrannosaurus) Thu May 22 1997 07:37

    Just read Note 6403.1....and I was wondering what's the
    matter while using 16 Bit I/O modules & BA356 box in the 
    following scenario (dual-node VmsCluster V6.2-1H3 on both 
    AlphaServer 1000As):
    
    
    KZPAA------BN21N-01----16 BIT I/O MOD-----BN21N-01-----KZPAA
                               BA356-KC
                               6 RZ29B-VA
    
    Should this work,granted we assign ID's 6 & 7 for KZPAA's ??
    
    I am asking because a Field Service guy failed to see any
    device from console mode.
    
    If he detached one of the cables (either of them,having 
    made attempts with both servers connected to the IN -
    primary SCSI port) then any server attached to the INPUT
    port would see ALL DEVICES.
    
    In order to get the devices "viewable" from cons. mode
    he had to resort to the 8 bit I/O mod. and related SCSI
    cables as follows:
    
    
    KZPAA------BN21H-01----8 BIT I/O MOD-----BN21H-01-----KZPAA
      
    
    Now since this is not (but I might be wrong) a VMScluster 
    issue,could anyone point out where's the rub in all this??
    
    What am I/We missing (besides the fact I should've configured
    the 8-bit i/o mod.right from the start.............).
    
    
    
    Thanks advancedly
    
    Regards
    
    Fab
T.RTitleUserPersonal
Name		DateLines
6714.1Smemorandum !!ROMOIS::FARRAUTOSic Semper TyrannosaurusThu May 22 1997 07:417
    Forgot to say,
    
    The BA356-KC is in DEFAULT single-bus mode (No BUS-SPLITTING
    terminators are currently installed).
    
    Fab
6714.2because....SUBSYS::VIDIOT::PATENAUDEAsk your boss for ARRAY's...Thu May 22 1997 11:586
The failure was seen because you had no termination to the upper 8 data bits in
the dual KZPAA 8bit configuration with the 16bit personality card. The drives
are unable to arbitrate on the bus. The use of a BA35X-MG card added this need
termination.

roger.