PDR vs MPD

why the USB Storage Driver's extend file name is ".MPD"
and the USB Card Reader Driver's extend file name is ".PDR"??

I know that's SCSI and non-SCSI Miniport Driver.
but...why??

thx

If the extend file name is ".MPD",it means the driver belongs to WDM structure; ...".PDR" means the driver belongs to VXD structure.
You can use anyone just depend on your favorite.The sample named UMSS of Microsoft is ".PDR".

Thanks for ur answer.

I know that and I had the sample.

All my firmwares follow mass storage class.

So I develop on Win9x.

I want to know what kind of product use WDM or VxD??
and why??

Ex1:USB H.D.D uses .MPD but I don't know why.
Ex2:USB Card Reader uses .PDR but I don't know why,too.

thx