Mode page proposal

scheible at vnet.ibm.com scheible at vnet.ibm.com
Thu Jan 5 13:56:42 PST 1995


========================================================================
   I have been authorized by X3T10.1 to present this proposal to X3T10
as recommended by X3T10.1.  I would appreciate your comments.
========================================================================
Accredited Standards Committee               Doc:      X3T10.1/94-___R0
X3, Information Processing Systems           Date:     7 September, 1994
                                             Project:  N/A
                                             Ref Doc.:
                                             Reply to:  John Scheible
To:        X3T10 Membership
From:      John Scheible, IBM

Subject:   Protocol mode page proposal

PROBLEM

Several physical interconnects use global IDs (including FC, SSA,
P1394), but SCSI does not have a common method of obtaining these IDs.
However, these IDs could be used by upper levels of SCSI (such as in the
Third party copy CDB creation).  If an Inquiry EVPD page or mode page
were created, the physical global IDs could be passed up to upper levels
of SCSI.

If a protocol specific mode page were created, then additional protocol
specific features could be controlled and documented in one place.


PROPOSAL

Create a new mode page for the SSA Unique_ID (global ID) and
programmable option block features.  These pages could be used by other
protocols also (i.e. protocol specific).  See the next page for the
official proposed wording.


ISSUES

1) Should the same mode page be used my multiple protocols?
2) Should the fields be unique across different protocols (no commonalitnforced)?

Sincerely,

John Scheible
Voice:  (512) 823-8208
FAX:    (512) 823-0758
Email:  Scheible at vnet.ibm.com

Page T.B.D.h - SSA Parameters

!-----+---------------------------------------------------------------!
! Byte!                            Bit                                !
!     +---------------------------------------------------------------!
!     !   7   !   6   !   5   !   4   !   3   !   2   !   1   !   0   !
!-----+-------+-------+-------+-------+-------+-------+-------+-------!
!   0 ! Rsvd=0! Rsvd=0!                Page code = TBD                !
!-----+-------+-------+-----------------------------------------------!
!   1 !         Page length = 0Ah                                     !
!-----+---------------------------------------------------------------!
!   2 !                                                               !
!  ...!         Unique_ID                                             !
!   9 !                                                               !
!-----+---------------------------------------------------------------!
!  10 !         Programmable 1 option block                           !
!-----+---------------------------------------------------------------!
!  11 !         Programmable 2 option block                           !
!-----+---------------------------------------------------------------!
    Table 1  Mode Select Data Format - Page T.B.D. (SSA Parameters)

This page describes some SSA parameters.  The programmable option block
bytes (10 and 11) are changeable.

Unique_ID defines the global ID which can be used to uniquely identify
an SSA node.  It does not uniquely identify either a LUN or a piece of
removable media.  This data can be used to identify a node for such
things as third party copy.

Programmable 1 option block defines the usage of the option block
function entitled Programmable 1.

Programmable 2 option block defines the usage of the option block
function entitled Programmable 2.

!---------+-----------------------------+-------------+---------------!
!  Value  !  Meaning                    !  Direction  !  Node Driver  !
!---------+-----------------------------+-------------+---------------!
!    0h   !  Node Installed             !  From node  !  Output       !
!    1h   !  Environmental warning      !  From node  !  Input        !
!    2h   !  Environmental failure      !  From node  !  Input        !
!    3h   !  Reserved                   !  Reserved   !  Reserved     !
!    4h   !  Port 1 ready               !  From node  !  LED Output   !
!    5h   !  Port 2 ready               !  From node  !  LED Output   !
!    6h   !  Serial In                  !  From node  !  Input        !
!    7h   !  Serial Out                 !  From node  !  Output       !
!    8h   !  Node off-line              !  From node  !  LED Output   !
! 9h-FFh  !  Reserved                   !  Reserved   !  Reserved     !
!---------+-----------------------------+-------------+---------------!
            Table 2  Programmable option block functions


NODE INSTALLED - A low active signal that indicates a node is installed.
This can be accomplished by pulling this signal high on the backplane
via a resister then having a device pull the signal to ground.  If the
device shorts the signal to ground on the circuit board (not
programmable), then a low active signal (below 0.8V) indicates that a
device is installed.  If the device uses the programmable nature of the
pin and determines it is programmed as "Node installed", then a negative
active signal (below 0.8V) indicates the device is installed and the
device is (or was) operational.

ENVIRONMENTAL WARNING  -  A low active signal that indicates a
non-critical problem in the environment.  When the device detects a low
active signal (below 0.8V), the actions will be protocol dependent.  In
the case of SCSI mappings, a deferred error will be generated with a
sense key/code/qualifier of T.B.D..  An example of an Environmental
warning is the failure of a redundant cooling fan.

ENVIRONMENTAL FAILURE  -  A low active signal that indicates a critical
problem in the environment.  When the device detects a low active signal
(below 0.8V), the device shall create an Async_alert message with a Type
field of Environmental failure.

PORT 1 READY  -  A negative active LED output which shall sync
sufficient current to light an LED when port 1 is in the ready mode.

PORT 2 READY  -  A negative active LED output which shall sync
sufficient current to light an LED when port 2 is in the ready mode.

SERIAL IN  -  An input signal to the device that carries serial data
using a T.B.D. protocol.

SERIAL OUT  -  An output signal from the device that carries serial data
using a T.B.D. protocol.

NODE OFF-LINE  -  A low active LED output which shall sync sufficient
current to light an LED when no ports to a device are receiving flags or
data.  This signal can be used to indicate that the device can be
removed with no impact to the system.  This is accomplished by having
the system place all ports in wrap mode that are transmitting to the
device to be replaced.  If the device to be replaced is functioning
enough to detect the loss of signals, then it can light the "Node
off-line" LED.

Thanks,
John Scheible
scheible at vnet.ibm.com
Voice (512) 823-8208




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