Smartosek Operating System Design And Space Optimization,

In the information age, embedded system technique is playing a critical role. It has a tight relation with traditional industrial control technologies and is combined with the newest software/hardware technology. Like desktop computers, embedded systems also need operating systems that facilitate users in developing and using. This kind of operating systems is usually named embedded operating systems. Nowadays, automotive electronics control software is tended to be larger and more complex which brings complexity to traditional front-back program development. Having analyzed the existing techology status and application status of RTOS aiming at electronics applications in modern industry, this thesis puts forward an OSEK/VDX-compliant embedded operating system, SmartOSEK. Related optimization techniques to minimize kernel memory space are discussed. The thesis is mainly foucused on the following topics:Firstly, we designed and implemented an OSEK/VDX-compliant OS, SmartOSEK. I was mainly dedicated to the development of several kernel modules covering scheduling, task management, resource management, interrupt management. This OS is featured by a hierarchical structure, rich peripheral interfaces, a reduced kernel componsed of necessary function modules. And it is also configurable and extensible. SmartOSEK only requires a low system overhead including ROM, RAM (less than 5K), and CPU (it can run in low-speed ECU like C51 single-chip). Till now SmartOSEK has been ported to multiple popular embedded ECUs. Based on the Priority Ceiling Protocol in OSEK standard, we introduce improvement techniques, treating internal resources and external resources differently, which in the mode of mixed scheduling, greatly reduces the overhead of resource allocation in context-switch.Secondly, since SmartOSEK is a static OS, we divide OS kernel code into smaller components configured by peripheral IDE, which leads to the minimization of kernel space. Compared with the original version, this kernel is smaller in size by 48%. In the term of minimizing application task code, SmartOSEK reuses the stack space of inconcurrent tasks. This thesis also brings forward a method to model static operating system. This method can abstract different components of static embedded operating systems, based on which the technique of computing minimal context of tasks is introduced. In evaluating the space performance of SmartOSEK, we construct a test platform including PC, MPC555 board, logic analyzer and achieve the best memory parameters of SmartOSEK. We have found SmartOSEK is comparable to other commercial OSEK-compliant OSs.This thesis is funded by the following grants: embedded software development platform aiming at automotive electronics(2003AAlZ2140), embedded software platofrm supporting digital devices(2004AAlZ2180).