understanding the SCSI Specification.

[amit mehta]

Linux SCSI layer, specifically SCSI mid layer is the place where
all the conversion happens. There is a Linux - SCSI mailing list
(linux-scsi) where you'll find relevant discussions.

-Amit

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.
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> 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."
>