selection timeout

[jmasker at attotech.com]

* From the T10 Reflector (t10 at t10.org), posted by:
* jmasker at attotech.com
*

*** Rant mode on ***
   THANK YOU for asking this question.  This has been a hot button with me
for quite some time.
   To me it is always PAINFUL to watch a system boot with multiple SCSI
adapters.  Some adapter setup utilities don't even have the ability to
change this parameter.  Whenever I can, I always back this down to 64 ms
and have never seen a problem.
   So to scan an empty bus takes almost 4 seconds.  Add to this the stupid
3 SECOND bus reset delay and we're up to 7 ... PER CHANNEL.  Now look at
the fact that the BIOS driver comes up first and must scan all channels,
typically one at a time, then the OS comes up and scans the channels one at
a time, and we're at almost 30 seconds for a motherboard with a
dual-channel SCSI built in.
   Granted, in the typical every day application environment, you aren't
sitting there booting all the time.  But in a test environment, I wonder
just how many man-hours are lost waiting.
*** Rant mode off ***




                                                                                            
                    "Neaz, Joe"                                                             
                    <Joe.Neaz at stra       To:     "'t10 at t10.org'" <t10 at t10.org>              
                    tus.com>             cc:                                                
                    Sent by:             Subject:     selection timeout                     
                    owner-t10 at t10.                                                          
                    org                                                                     
                                                                                            
                                                                                            
                    05/06/02 03:37                                                          
                    PM                                                                      
                                                                                            
                                                                                            




* From the T10 Reflector (t10 at t10.org), posted by:
* "Neaz, Joe" <Joe.Neaz at stratus.com>
*
Is there a generally accepted value for selection timeout that is more
reasonable for current Ultra160 disk drives than the SCSI spec of 250ms? We
are trying to reduce the amount of time it takes to rescan the SCSI bus and
waiting 250ms for non-existent device ID's takes a lot of time.

Thanks,
              Joe

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