Source:SELF_IMPR Xiaohui // my0919’s blog
1. Common Differences Analysis
2. Advantages and Disadvantages Analysis of Linux and VxWorks
1) VxWorks adopts a microkernel structure, which has better kernel portability than Linux, higher kernel stability, and reduces memory overhead. Inter-process communication is achieved through IPC (Inter-Process Communication mechanism); Linux adopts a monolithic kernel structure, which has poorer kernel portability than VxWorks, a larger kernel maintenance workload, and due to the inclusion of file systems and device drivers, the system kernel is relatively large, increasing memory requirements. However, communication between kernel modules is achieved directly through function calls, improving kernel efficiency.
2) In terms of real-time performance: VxWorks adopts a hard real-time interrupt response mechanism, truly achieving real-time task responses and requiring event processing to be completed within a specified time; while Linux adopts a soft real-time mechanism, which does not guarantee time determinism. Therefore, in scenarios with high real-time requirements, VxWorks has a significant advantage over Linux;
3) Technical Aspects:
A. The address space between the Linux kernel and user processes is isolated. The address space between each user process is isolated, so when a user process crashes, it does not affect the operating system kernel and other user processes’ normal operation;
B. Linux supports page-level memory management and supports paging;
C. Due to the isolation, the coupling between different parts of Linux software is smaller, and there is a clear interface between Linux applications and the kernel, the POSIX API. In summary, Linux fully utilizes the MMU hardware of modern microprocessors, while VxWorks adopts a flat address space. In some high-end devices, Linux’s protected mode can indeed make the system more stable and easier to debug.
4) Other objective factors: The main reason for network device manufacturers turning to Linux is that Linux represents a more mature industrial chain, and the development cost of using Linux will be far lower than that of VxWorks. This is mainly reflected in:
(a) The number of software supporting Linux is increasing, while the number of software supporting VxWorks is decreasing. There are many open-source software under Linux, most of which do not support VxWorks. Commercial software used for network devices almost all support Linux, such as: Gated, Zebos, Trillium, InterPeek’s protocol stack, etc.
(b) Almost all chips provide Linux drivers, and almost all CPUs and evaluation boards provide Linux support.
(c) It is easier to find developers familiar with Linux. Compared with Linux, VxWorks is increasingly appearing to be niche, and its living environment is becoming worse.
In summary, in small-scale applications with high real-time requirements, VxWorks is more practical than Linux, while in relatively large-scale applications with less strict real-time requirements, Linux has more advantages.
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Copyright Statement: This article is an original article by CSDN blogger “my0919”, original link: https://blog.csdn.net/my0919/article/details/86525157
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