An elementary question about HwScsiTimer routine in scsi miniport driver

I am writing a virtual scsi miniport driver,
and there is no HwScsiInterrupt routine in it.

Can anyone tell me:
what’s the use of HwScsiTimer routine in a scsi miniport driver
and
When do i must have HwScsiTimer routines in my scsi miniport driver.

thanks in advance!!


Ãâ·ÑÏÂÔØ MSN Explorer: http://explorer.msn.com/lccn/

> I am writing a virtual scsi miniport driver,

and there is no HwScsiInterrupt routine in it.

There are only lame ways of doing this using SCSIPORT, since
SCSIPORT/STORPORT are not suited for such tasks at all due to locking
issues.
Using timer is one of these lame ways - too slow.

The correct way is writing a full storage port driver, and there are
libraries which can help you with this task.

Max

Well since you are asking about HwScsiTimer, I am assuming that you cannot
complete an SRB in HwStartIo.

You will need to call the ScsiPortNotification(RequestTimer,) function at
the end of your HwStartIo since this is the only way, without an interrupt,
to get SCSIPORT to invoke its DpcForIsr, and call your DPC callback
(CallEnableInterrupts) so that you can delay SRB completion. You may also
need to call that function at the bottom or your timer routine.

Remember that using this function is going to incurr a quantum delay of
around 10 ms per invocation, even though the timer resolution is in
microseconds. If this is not the response you expect, then my suggestion is
to abort development using SCSI/STORPORT and seek a third party support
library such as www.StorageCraft.com.

HwScsiTimer is the only way you can defer the completion of an SRB.


Gary G. Little
Have Computer, Will Travel …
909-698-3191
909-551-2105
http://www.wd-3.com

“? ?” wrote in message news:xxxxx@ntdev…
>
> I am writing a virtual scsi miniport driver,
> and there is no HwScsiInterrupt routine in it.
>
> Can anyone tell me:
> what’s the use of HwScsiTimer routine in a scsi miniport driver
> and
> When do i must have HwScsiTimer routines in my scsi miniport driver.
>
> thanks in advance!!
>
>
>
>
>
> _________________________________________________________________
> Ãâ·ÑÏÂÔØ MSN Explorer: http://explorer.msn.com/lccn/
>
>
>
>