difference between pseudo devices and native devices

Hi!

I am assuming you are referring to this in relation to PowerPath. By definition:

A Native device is a device created by the operating system to represent and provide access to a logical device. Normally, a native device is path aware and represents a single path to a logical device. The device is native in that it is provided by the operating system for use with applications. PowerPath supports native devices on all platforms except AIX.

Pseudo device is a special kind of device (operating system object used to access devices) created by PowerPath. It is path independent once PowerPath is installed. When a pseudo device is created, there is only one per path set.

So the bottom-line is that the Native device is created by the OS while a Pseudo device is created by PowerPath. Both provide a device definition with a defined path.