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