Help !

Kaushik Datta kdatta at npd.hcltech.com
Thu Dec 20 07:38:46 GMT 2001


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Hello all,

        I am stuck up in a problem related to the SCSI subsystem.
        I have a requirement that says the following to be done ...

        "A  SCSI pseudo host adapter driver for FreeBSD 4.2 that simulates  a SCSI host
         adapter driver but does not interface with any actual hardware.The SCSI
         disk driver issues SCSI commands to the SCSI pseudo host adapter driver which in
         turn forwards the requests to the actual SCSI host adapter driver to issue the
         actual SCSI command. The driver is recognized by the system as a PCI SCSI
         host  adapter driver and assigns it a SCSI bus ID different from the actual
         SCSI host adapter(s). The driver can be accessed via device files
         /dev/dsk/cXtYdZ which have the same major number as the actual SCSI disk
         devices and X is equal to the SCSI bus ID. "

         I am not able to understand what is meant from the above..
         Can any one please explain me the exact requirements ??

         ALso how do I approach writing the driver, the steps involved etc etc..

         Thanks a lot !
         Kaushik



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<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<tt>Hello all,</tt><tt></tt>
<p><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I am stuck up in a problem
related to the SCSI&nbsp;subsystem.</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I have a requirement
that says the following to be done ...</tt><tt></tt>
<p><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "A&nbsp; SCSI pseudo
host adapter driver for FreeBSD 4.2 that simulates&nbsp; a SCSI host</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; adapter driver
but does not interface with any actual hardware.The SCSI</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; disk driver issues
SCSI commands to the SCSI pseudo host adapter driver which in</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; turn forwards
the requests to the actual SCSI host adapter driver to issue the</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; actual SCSI command.
The driver is recognized by the system as a PCI SCSI</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; host&nbsp; adapter
driver and assigns it a SCSI bus ID different from the actual</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SCSI host adapter(s).
The driver can be accessed via device files</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /dev/dsk/cXtYdZ
which have the same major number as the actual SCSI disk</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; devices and X
is equal to the SCSI bus ID. "</tt><tt></tt>
<p><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; I am not able to
understand what is meant from the above..</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Can any one please
explain me the exact requirements ??</tt><tt></tt>
<p><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ALso how do I approach
writing the driver, the steps involved etc etc..</tt><tt></tt>
<p><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Thanks a lot !</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Kaushik</tt>
<br><tt>&nbsp;</tt>
<br><tt>&nbsp;</tt></html>

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