SE LVD Hot Swap

Gerry Johnsen gerry at
Wed Oct 16 10:49:09 PDT 1996

* From the SCSI Reflector (scsi at, posted by:
* Gerry Johnsen <gerry at>
Maybe I am misinterpeting something but it appears to me there is a 
more serious problem with hot swapping SE devices on a active LVD bus 
then the state of the diff sense line.  When the SE device is attached 
it will immediatly tie all +signal lines (+DB0-+DB16, +REQ, +ACK, ect) 
to ground.  This will halt any current LVD activity in progress and 
prevent any successful bus activity until the whole bus switches to 

Due to the complexities in implimenting case 4 hot swap between LVD 
and SE devices I would recommend it is outside the scope of SPI-2 and 
only addressed in future proposals if a market need is identified.

Gerry Johnsen                           Ciprico Inc
voice (612)551-4000                     The Disk Array Company
fax (612)551-4002                       2800 Campus Drive
gerry at                       Plymouth, MN 55441

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