Real-time Distributed System Based On Linux And Study On The Process Migration

The present system softwares in the domestic are basicallycornered by oversea softwares, so national software industry isencounter with great diffculty and it is diffcult to ensure our country'sinformation safety. The emergence of the Linux operating systemdoubtless makes us start from a high originating point, creatingenormous chances for our country 's development of system softwares.Some important fields such as modern national defense andaviation present much higher request fOr the real-time and reliability ofcomputer. The tenth-five(year national defense pre-research pro j ect-" embedded real-time distributed system ') requires real-timecorrespondence, accomplishing fault-tolerant of server (redundance ofthree processors, inserting and pulling out when the processors arepowered, loose synchronization among processors), fault-tolerant ofnetwork(redundance of double circuit), fault-tolerant of tasks. Thepaper mainly studies on the process migration. Process migration canachieve fault-tolerant of tasks, consequently improving the reliabilityof the system. For comparing it with oversea mature real-time operatingsystem and taking account of sharing of the kernel sound codes inLinux, the system decides to adopt the renovation based on Linux.The paper includes six chapters. The first chapter is forward,introducing the research background, distributed system, Linux and thedevelopment of process migration in the domestic and oversea. Fromthe second chapter to the fifth chapter, they principally analyze theLinux kernel sound code. The second chapter studies the hardwarestructure and software system of the" embedded real-time distributed, system". The third chapter and the fOrth chapter deeply analyze theprocess management and memory management in Linux system. Theyanalyze the process creating, executing, dying and process schedulealgorithm, beginning with the conversion of the process state.Meanwhile, 'the paper discusses the procedure of mapping the virtualaddress into physical address, assigning and reclaiming of the physicalpage and process memory organizing. The fifth chapter compares the time-sharing Linux with real-time system, adopting the method of directly inserting a real-time kernel from the bottom to implement real-time of the Linux operating system. The sixth chapter discusses the setting of checkpoint in the process migration, creating of checkpoint files and so on. In this chapter, it puts forward a new system about checkpoint, avoiding the Domino-effect and livelock .It realizes the storage of process context and other states with the form of executing file in the diskette by using checkpoint system and applying the page switching principles in Linux. Consequently, when the process has wrong at the checkpoint, it can move out the process in the fault machine, then choose other normal machine, continue to execute from the interrupted point, finally achieve the process migration and load balance of the system.