understanding the SCSI Specification.

[RKK]

Hi

On Tue, Aug 2, 2011 at 9:36 PM, amit mehta <gmate.amit at gmail.com> wrote:
> Linux SCSI layer, specifically SCSI mid layer is the place where
> all the conversion happens
yeah im trying to understand how the abstraction is provided .
. There is a Linux - SCSI mailing list
> (linux-scsi) where you'll find relevant discussions.

 I have posted there also but no luck:(

>
> On Tue, Aug 2, 2011 at 12:15 PM, RKK <kulkarni.ravi4 at gmail.com> wrote:
>> Hi Amit
>>> download sg3-utils and its source code. good place to begin with.
>>
>> Thanks for the reply.
>> I believe the sg3-utils uses the linux sg driver which does not
>> provide any abstraction and sends commands directly to the device.
>> what i was looking was more of protocol specific information and
>> explaination of the flow like how block device read , write requests
>> are converted into Commands and how those SCSI commands are passed to
>> the lower layer. My target is FPGA board which has a pci interface for
>> host controller . can u give me some pointers to understand the below
>> ?
>>
>> Warm Regards,
>> Ravi Kulkanri.
>>
>>>
>>> On Mon, Aug 1, 2011 at 2:41 PM, RKK <kulkarni.ravi4 at gmail.com> wrote:
>>>> HI all,
>>>> Im working on a storage protocol   which uses SCSI commands  set as
>>>> the command set and also the SCSI Task Management functions for
>>>> processing the Task Management.
>>>> The Architectural Model is based on SAM-5. The Command set is based on
>>>> SPC-4 and SBC-3. I have some doubts in trying to understanding some
>>>> SCSI terms and definitions.
>>>>
>>>> For  using the send command transport protocol service request to
>>>> request a initiator  the following API is defined
>>>>
>>>> [1]Send SCSI Command (IN (I_T_L_Q Nexus, CDB, Task Attribute, [Data-in
>>>> Buffer Size], [Data-
>>>> out Buffer], [Data-out Buffer Size], [CRN], [Command Priority], [First
>>>> Burst Enabled]))
>>>>
>>>> Here  I want to know what relation does the I_T_L_Q tries to convey.
>>>> from what it says in SAM-5 Specification  section 4.8 tries to define
>>>> the Nexus as " nexus represents a relationship between a SCSI
>>>> initiator port, a SCSI target port, optionally a logical unit,
>>>> and optionally a command."
>>>>  how do we convey this information in the above [1].
>>>> Also can someone help me in how to map the initiator-target relation
>>>> to host-device  structure? thanks.
>>>>
>>>> Warm Regards,
>>>> Ravi Kulkarni.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Warm Regards,
>>>> Ravi Kulkarni.
>>>>
>>>> _______________________________________________
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>>>> Kernelnewbies at kernelnewbies.org
>>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>>
>>>
>>
>>
>>
>> --
>> Warm Regards,
>> Ravi .
>> "I don't Know is not a excuse , its an opportunity."
>>
>



-- 
Warm Regards,
Ravi .
"I don't Know is not a excuse , its an opportunity."