Protection Extension of µITRON4.0 Specification is to add access protection functios of kernel objects including memory area to the µITRON4.0 Specification, the latest version of the µITRON real-time kernel specification which is a de-facto industry standard in the embedded systems field. "µITRON4.0/PX Specification" is an abbreviation of "Protection Extension of µITRON4.0 Specification" (PX stands for "Protection eXtension").
The whole specification document can be downloaded from here.
Protection Extension of µITRON4.0 Specification was designed by the Memory Protection Function SWG under the Version-Up WG of the TRON Association and was publised in June, 2002.