IWSFT /11/ A Layered Formal Specification of Contactless IC Card "FeliCa" Kyushu University (JAPAN) Xiaojing ZHANG, Yoichi OMORI and Keijiro ARAKI Background  Consumer embedded systems Product family development Short interval between releases Similar service with variable platform  Software productline Extracts commonalities of a series of products Manage and improve core asset Application Engineering Domain Engineering Management Core Asset

IWSFT /11/ Feedback process from product to core asset is complicate  Product is complicatedly mixed  Which part should we feedback to the core asset? Formal specifications help clarifying commonalities and differences Purpose  Propose a layered architecture of specification To improve efficiency of the feedback process Approach  Separate descriptions between logical and physical level by hardware dependency  Apply to Contactless IC card "FeliCa“

IWSFT /11/ Core Asset Software Product feedback specification in natural language Physical Layer (variable components) Logical Layer (common components) ＋ reuse Layered Architecture Figure1: Concept Of Research separation

IWSFT /11/ Method  Layered architecture Logical layer  preserved data with logical meaning  Operations derived from design purpose Physical layer  Physical structure of data  Algorithms or procedure of operations 1. Divide natural language specification into several modules 2. separate each module into Logical Layer and Physical Layer by principles above 3. Draw class diagrams in UML, and then materialize them to VDM++ 4. Inheritance are used temporarily Gathering only physical descriptions can’t make the layer complete To make up shortage; To indicate correspondency

IWSFT /11/ Case Study: FeliCa Card  Divide card into file system and commands File System – data structure on card memory  Data hold on the memory area Operations access the data  Type of the data Operations about types Commands – protocol between card and R/W  Command/Response packet Command purpose  Structure of packet Procedure of command’s operation Future Works  Improve and formalize the method How to express both independency and correspondency? Logical Layer Class Physical Layer Class Logical Layer Class Physical Layer Class

IWSFT /11/ Class of Logical Layer File System inheritance Figure2: Class Diagram Of Commands (partial) Class of Physical Layer Module: Command Polling