How to send SRBs directly to PORT driver in Windows 9x?

Hello,

I am developing a storage device layered driver for DVD device. The intention of this driver is to give interface to win32 application. So that win32 application will send commands to this driver. Based on the command I want to send SRBs to port driver.

My driver sits above the port driver (ESDI_506.PDR and SCSIPORT.PDR) and below the SCSI1HLp.vxd (I am creating my driver with DRP_SCSI_LAYER_BIT flag).

Here, I have lack of information that How to send SRBs to lower layer PORT driver. And how to call PORT driver request routine.

FYI: In ASPI model, ASPI Helper VSD (APIX.VXD) directly calling port driver functions. I don’t know how it is.

Help appreciated.

Thank you,
Bala