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<span style="font-size: 11pt;">Hi,</span></div>
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<span style="font-size: 11pt;">I am trying to understand how to use DiskSim for a shared system, while using it under system simulator (i.e. <em>DiskSim as slave</em>). I am new to DiskSim, so had problem figuring something out, and wondering if I'm even doing
it the right way. I would really appreciate if you would be able to help me with the following question and problem I faced:</span></div>
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<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><strong>Question on concurrent access: </strong><br style="">
</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">Is it possible to submit a new request to DiskSim before an outstanding request is processed? Here, I basically want to create a situation where there are multiple concurrent IO
request in the disk queue.</span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><br style="">
</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><strong style="font-size: 11pt;">Details:</strong></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">And here are details of what I was trying to achieve, steps I have tried with syssim_driver.c code, and the problem I have faced:<br style="">
</span></p>
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</strong></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><strong style="font-size: 11pt;">----------</strong></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><strong><em>Original arrival of syssim: </em></strong><br style="">
</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">I noticed that the example code<em> syssim_driver.c</em> generates new IO requests only after an existing request is processed till its completion.</span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><strong><em>Modified arrival with overlap: </em></strong><br style="">
</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">I changed the example code to add second requests before the first request is complete (e.g., before calling disksim_interface_internal_event). <br style="">
</span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);"><strong><em>Used disksim_request.id to track request's progress:</em></strong></span></span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">I also wanted an ability to track </span>when a specific I/O request completed.
So, I utilized the field "id" of disksim_request: set a unique value to each request in main method, and read values "<strong style="">id</strong>" and completion time "<strong>t"</strong> in method syssim_report_completion. </span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><em><strong>Problem:</strong></em></span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">- <span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">Original arrival of syssim:</span><strong> worked fine:</strong> id and
t were unique for each requests, and values looked correct.</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">- <span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">Modified arrival with overlap</span>: <strong style="">Had this problem
</strong>- each time <span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">syssim_report_completion</span> was invoked, its parameter disksim_request *r seemed to have same value (r.id, r.bytecount, r.start).</span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;"><span style="font-family: Calibri, Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">I performed these tests with disksim 4.0, with hdd and ssd models (FlashSim). </span><br>
</span></p>
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</span></p>
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</span></p>
<p style="margin-top: 0px; margin-bottom: 0px;"><span style="font-size: 11pt;">Could you suggest if I am doing anything wrong here? Or is it possible that this problem is coming due to known limitation of Disksim? </span></p>
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<div class="PlainText"><span style="font-size: 11pt;">Regards,</span><br style="font-size: 11pt;">
<span style="font-size: 11pt;"></span><span style="font-size: 11pt;">Sagar Thapaliya</span><br>
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