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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

502.0. "Mixed wide and narrow SCSI?" by HGOVC::PATRICKNG () Wed Feb 19 1997 04:35

    Hi,
    
    Can wide and narrow SCSI devices installed on a BA36R for 4100 5/400 
    Pedestal?
    
    KZPDA-----BN21K-02----BA36R-SB--BA36X-MG---RZ29-VW+RZ28-VA+TZ88N-VA
    
    The above configuration mixed wide and narrow SCSI devices on BA36R
    with 8bit I/O module. Is it a supported configuration?
    
    Thanks,
    Patrick
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502.1EEMELI::MOSEROrienteers do it in the bush...Wed Feb 19 1997 06:0513
    mixing wide and narrow disk drives in a wide shelf (assuming the narrow
    drive has its firmware up to a good rev level) will normally result in
    narrow negotiation also for the wide drive, i.e. SCSI will just talk
    8-bit.
    
    Mixing also a narrow tape drive into this picture makes things worse
    and in your configuration I'd expect it not to work at all, i.e. you
    wont see all the devices in the shelf from the host.
    
    The best bet is to buy a (cheap) KZPAA and either take an old BA350
    shelf, or a wide shelf with a 8-bit personality module.
    
    /cmos
502.2POBOXB::BAKFri Feb 21 1997 09:456
HI,

There is NO need to buy a BA350 narrow shelf. All the devices listed will work
fine in a BA36R wide shelf.

	Dennis 
502.3Just to set the record straight . . .SUBSYS::BROWNSCSI and DSSI advice given cheerfullyMon Feb 24 1997 10:4618
    re: 502.1
                          
    > mixing wide and narrow disk drives in a wide shelf (assuming the narrow
    > drive has its firmware up to a good rev level) will normally result in
    > narrow negotiation also for the wide drive, i.e. SCSI will just talk
    > 8-bit.
    
    	This is just plain false.  Wide drives will continue to talk wide.
    
    > Mixing also a narrow tape drive into this picture makes things worse
    > and in your configuration I'd expect it not to work at all, i.e. you
    > wont see all the devices in the shelf from the host.
    
        There used to be a problem with putting narrow devices into wide
    	boxes (see SSAG::ASK_SSAG), and the symptom was that wide devices
    	couldn't be seen after a narrow device was installed.  The problem
    	was fixed about two years ago; any narrow disk or tape built since
    	then should be OK.