Name that multi-port SCSI device

Gerry_Houlder at notes.seagate.com Gerry_Houlder at notes.seagate.com
Tue Jun 15 10:52:28 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* Gerry_Houlder at notes.seagate.com
*
There is one other distinction between the words "Device" and "Target". The
standard uses Device to denote anything attached to SCSI bus, which could
be either an initiator, target, or both. Thus a target is a more specific
type of device.

In the context of our discussions, multi-port things are typically targets.
The standard tries to be very explicit about the behavior of targets in
various circumstances but is typically silent about the effects of most
features on initiators. This is rooted in our "ancient" attitude that
targets need to be interchangeable (and therefore precisely defined) but
initiators need not be similarly constrained. Perhaps we need to discuss
the characteristics of a multi-channel initiator as well as the
characteristics of a multi-ported target?





Gene_Milligan at notes.Seagate.COM on 06/15/99 10:06:08 AM

To:   "Binford, Charles" <charles.binford at lsil.com>
cc:   t10 at lsil.com (bcc: Gerry Houlder)

Subject:  RE: Name that multi-port SCSI device




* From the T10 Reflector (t10 at symbios.com), posted by:
* Gene_Milligan at notes.seagate.com
*
<<What is difference between the words 'Device' and 'Target'?>>

     The SCSI device has a target, at least one LUN, and at least one
device server. The Target has an address and capability to pass stuff to at
least one LUN but no device server.

<<How
significant of a difference is there between the phrases
- "a SCSI device for each port"  and
- "a SCSI target for each port">>

     Not very to the main point I was making. I focused on SCSI device due
to the subject of the thread. However SCSI device conveys the original
issue in my mind of the shared device server (e.g. R/W media) between the
two SCSI devices (ported by the two targets).

Gene


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