Hi

On Tue, Aug 2, 2011 at 9:36 PM, amit mehta [off-list ref] 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 [off-list ref] wrote:

quoted

Hi Amit

quoted

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.

quoted

On Mon, Aug 1, 2011 at 2:41 PM, RKK [off-list ref] wrote:

quoted

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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--
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."