Hello libusb-devel,

Recently I have been going through the Libusbk.sys driver source to check the IOCTLs it uses. I realized that the User-Mode dll files are using DeviceIoControl for all the communications with the device. 

But there are two callbacks registered, namely EvtIoRead and EvtIoWrite, which according to my understanding will get called if the application/dll calls ReadFile or WriteFile functions. 

I was just wandering why we are using IOCTLS for Bulk IN/OUT transactions instead of using ReadFile and WriteFile functions?

Best Regards,
Pradeepa Senanayake.