The Design And Implement Of Linux Modules Of OSAL In DOPRA

In the development of embedded software, OS (Operating System) plays a more and more important role. Now there are a large number of commercial OS, such as VxWorks, WinCE, QNX, and so on. But they cost too much, which will increase the cost of pruducts. As open source software----Linux which is powerful and has extensive support of platforms, can be gained free, so Linux has a wide future in embedded development.This article "The Design and Implement of Linux modules of OSAL in DOPRA" is a part of project "Transplanting LAD132 from VxWorks to Linux". This project investigates the feasibility of Linux as embedded OS, and IAD132 is a connecting device of narrow-brand. DOPRA (Distributed Objected Programming Real-time Architecture) which is used in IAD132, is a software platform as virtual OS. DOPRA screens the differences of OS and provides uniform interface upward. OSAL (Operating System Adapter Level) is a part of DOPRA, and it has relationship with OS directly. Its purpose is to implement modules correlative with OS, and provide uniform interfaces for upward modules.The content of the article is about the design and implement of Linux modules of OSAL, which encapsulates the API (Application Programming Interface) provided by Linux, to implement the modules: semaphore, read and write lock, management of IO, management of system time, management of task, management of memory. There are different methods of implement in user-state and kernel-state. This article also introduces how to build the embedded linux environment, including: selecting of library, making cross-compiler, selecting of file system and so on.By transplanting IAD132, the conclusion can be gained: the performance of kernel-state in Linux is equal with it in VxWorks. Affected by switch of processes and system calls, the performance of user-state will drop observably, but by putting major work in single process and sharing memory in user-state and kernel-state, the performance will approach it in kernel-state. So, as long as proper model is used, it is feasible to use Linux as embedded OS.