SAS Phy layer _ some queries

Elliott, Robert (Server Storage) elliott at
Thu Aug 26 11:51:23 PDT 2004

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert (Server Storage)" <elliott at>

> -----Original Message-----
> From: owner-t10 at [mailto:owner-t10 at] On Behalf Of Mona
> Sent: Monday, August 23, 2004 6:44 AM
> To: t10 at
> Subject: SAS Phy layer _ some queries
> * From the T10 Reflector (t10 at, posted by:
> * Mona <monika.talwar at>
> *
> I am studying SAS1.1 specifications.  
>  I have some queries related to the SAS specifications
>  -- For how much time shall state machine wait for some transmitted
>   messages from transmitter, for example COMSAS transmitted?

That is design-specific. The "Transmitted" signals are conceptual
signals for the purpose of the standard between an independent state
machine and an independent transmitter.  They might not really exist in

>  --Will receiver be able to detect the "completion" of 
> detected OOB signal without detecting negation time(6.5)?

It's not supposed to.  If the negation time is not present, then
it is not a completely valid OOB signal.  The "Detected" messages are
triggered but not the "Completed" messages.

>  --"Address frames shall not be terminated early". What's 
> meant by early termination??(7.8.1)

Sending less than 7 dwords before the CRC (i.e. 8 dwords before the
EOAF).  For example, skipping the last dword of an IDENTIFY because it's
"reserved" is not allowed.

It's also inadvisable to start sending a BREAK while in the middle of
sending an address frame.

>  -- On page 27 (4.1.2) it is stated that SAS phy may use different 
>  roles(initiator or target)  in different connections. On 
> page 119(6.6.5) it 
>  is stated that SAS target phys should not originate a new 
> phy reset sequence 
>  after their first attempt. How is target/initiator device 
> exepected to 
> behave  if its first attemt of phy reset sequence fails?

If it has initiator things to do (i.e. wants to discover targets to send
them commands), then it should keep rerunning the phy reset sequence to
search for something newly attached.

If it has no initiator things to do (e.g. it is a tape drive with an
EXTENDED COPY copy manager, which can act as an initiator after being
given some work to do, but it has no such work pending) then it should
follow the target advice and let whatever it is attached to discover it

> Mona 
> nSys
> Solutions for emerging standards

Rob Elliott, elliott at
Hewlett-Packard Industry Standard Server Storage Advanced Technology

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