understanding the SCSI Specification.

[RKK]

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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>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>
>



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