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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

6642.0. "another NCR810 SCSI question ???" by SAYER::ELMORE (Steve [email protected] 4123645893) Thu May 01 1997 13:51

    Sorry if asked before.  It's hard to find in this large conference.

    
    Can Fast Wide SCSI-2 disks (a Seagate 31230W [Digital PBXRW-EB, I think])
    run off a NCRC810-based controller?

    I have a WNT-Alpha with a CDROM and an old RZ23 that the AlphaBIOS can
    see as connected to a NCRC810 controller.  When I add the Seagate
    above, it's not seen.  The Seagate uses a 68-pin connector.  The
    internal SCSI cabling is 50-pin.  I'm using a H4086-AA 50/68-pin
    adapter for the connection.

    My understanding is Fast Wide SCSI is compatible but will run at the
    narrow speed.  Reference "DECstation" conference:

    >=========================================================================
    >Note 7103.1                 DECpc XL590 configuration                 
    >TARKIN::LIN "Bill Lin"                               61 lines 
    >23-AUG-1996 02:26
    >-------------------------------------------------------------------------
    >	.
    >	.
    >	.
    >>>         compatible with SCSI "fast" or "wide" (or both) devices ?
    >
    >    Correct, the SCSI is based on the NCR 810 chip.  It should be fast
    >    compatible (i.e. 10MHz SCSI).  Wide devices will run as narrow devices
    >    on the 810.

    =====
    AlphaBIOS "Display System Configuration"

    SCSI Configuration

      NCRC810 #0, SCSI ID 7, SCSI Bus 0
    -------------------------------------

    SCSI ID  Device        Size      Description
    -------  ------       ------     ----------------------------------------
       2     Disk 0       100 MB     DEC     RZ23     (C) DEC0A18
       5     CD-ROM                  Toshiba CD-ROM XM-4101TA1084
    
    
    Thanks,
    Steve
T.RTitleUserPersonal
Name		DateLines
6642.1Wide box?CSC32::M_DIFABIOMOVL #OPINION,EXE$GL_BLAKHOLEThu May 01 1997 16:405
    I believe you would need to install the wide drive in a wide type
    box. (BA356) You cold then connect it to a narrow controller, and it
    would run in narrow mode.
    
             Mark d.
6642.2SUBSYS::VIDIOT::PATENAUDEAsk your boss for ARRAY's...Fri May 02 1997 00:446
    
    You can also connect them to a narrow cable IF you can supply proper
    termination to the upper 8 bits. Or if daring float them and use the
    bus at the end with term enabled.
    
    Roger.
6642.3WRKSYS::BCLARKI have dyslexia of the fingersFri May 02 1997 07:039
    As Roger said, if the system internal cable provides bus termination,
    you can use a wide-narrow cable adapter. We do this in (alcor) 
    Alphastation 600 for narrow drives. The adapter used in Alcor is:
    
    	17-04009-01 and the saleable is PBXKP-BA
     
    cheers,
    
    bc
6642.4unclear about PBXKP-BA?SAYER::ELMORESteve [email protected] 4123645893Fri May 02 1997 14:4816
     >   As Roger said, if the system internal cable provides bus termination,
     >   you can use a wide-narrow cable adapter. We do this in (alcor) 
     >   Alphastation 600 for narrow drives. The adapter used in Alcor is:
     >   
     >       17-04009-01 and the saleable is PBXKP-BA
     
     Sorry, I'm not quite clear about this.  Is the PBXKP-BA the
    wide-narrow cable adapter or the terminator?
    
    I'm using an H4086-AA 50/68-pin adapter.
    
    For SCSI termination, can not the Seagate drive be terminated via the TE
    jumper on it?
    
    Thanks,
    Steve
6642.5SUBSYS::VIDIOT::PATENAUDEAsk your boss for ARRAY's...Fri May 02 1997 15:276
    
    I don't know the answer to the part number part. But, yes you can
    enable termination on the drive, but it has to be at the END of the
    bus if you do, and the bus CANNOT have the upper eight bits grounded.
    
    roger.
6642.6Internal cable directly to disk, no Storage Box. Right?CSC32::M_DIFABIOMOVL #OPINION,EXE$GL_BLAKHOLEFri May 02 1997 18:506
     So are you saying a Wide drive can be placed in a narrow box and it
    will work? Where do the high 8 data bit lines get terminated? Or are
    you connecting the interal cable (with termination) directly to the
    Disk?
    
                  Mark d.
6642.7SUBSYS::VIDIOT::PATENAUDEAsk your boss for ARRAY's...Fri May 02 1997 20:224
    we are talking on a cable
    
    no way in a ba350 or ba353.
6642.8PBXKP-AA ?? / grounded eight bits ??SAYER::ELMORESteve [email protected] 4123645893Mon May 05 1997 10:0121
    Can anyone tell me what the PBXKP-BA is?
    
    Also, regarding:
    
>   I don't know the answer to the part number part. But, yes you can
>   enable termination on the drive, but it has to be at the END of the
>   bus if you do, and the bus CANNOT have the upper eight bits grounded.
    
    I found the Seagate user's guide out on the web.  I jumpered the TE. 
    I'm at the end of the NCR810-based bus (for one test, it was the only
    drive on the bus).  My system can still not see the drive.
    
    How would I determine if the upper eight bits are grounded or not?
    
    By-the-way, this is a Digital disk...I just can't tell you the product
    name (got two off DIAL and are new).
    
    thanks,
    steve