PX4固件适配 | LiamY’s Blog

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关于实时操作系统的部分

NuttX是什么

文章浏览阅读1.2w次，点赞20次，收藏47次。NuttX支持大多数RTOS都没有实现的进程概念，并提供完整的POSIX API，比如pthread、信号量、消息队列、时钟/定时器、信号、环境变量等。同时，也支持RTOS上常见的优先级翻转和tickless模式。NuttX支持对称多处理（SMP）和非对称多处理（AMP）两种多核编程模式，开发者可以根据芯片设计的特点和应用场景的需求，选择使用SMP或AMP，甚至同时使用SMP和AMP。_nuttx

https://blog.csdn.net/yyz_1987/article/details/133077352

NuttX是一个成熟的实时操作系统，于07年由Gregory Nutt先生正式开源，2016年被三星选为TizenRT操作系统的内核，2019年在小米的推动下正式进入Apache基金会，经过开源社区多年的不懈努力，NuttX功能丰富，性能稳定，商业化成熟度高，Fitbit最近两代的手环产品和索尼多款消费级产品都是基于NuttX开发的。 NuttX可运行于各种处理器架构和硬件平台上，包括ARM、MIPS、AVR等其重点遵从特定的标准并且尽量可伸缩良好且可适应从8位到32位单片机环境，在stm32上也能跑。Nuttx主要遵循的标准是 Posix和ANSI标准。

和Linux操作系统比较：

大小和效率：Nuttx是一个非常轻量级的操作系统，具有小巧的内核和较低的内存占用。相比之下，Linux系统通常较大且较复杂，需要更多的资源。

实时性：Nuttx是一个实时操作系统，可以提供精确的时间管理和响应。这对于需要严格时间控制的嵌入式应用非常重要。Linux系统虽然可以提供实时性，但通常需要额外的配置和补丁。

可移植性：Nuttx被设计为高度可移植的，可以在多种硬件平台上运行。它支持许多不同的处理器架构和设备。Linux系统也具有很高的可移植性，但在某些嵌入式设备上可能需要更多的定制和适配工作。

Table of Contents

About Apache NuttX — NuttX latest documentation

https://nuttx.apache.org/docs/latest/introduction/about.html

POSIX是什么：

Portable Operating System Interface(POSIX IPA: /ˈpɒz.ɪks/[1]) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system and user-level application programming interfaces(APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers.

POSIX

The Portable Operating System Interface (POSIX; IPA: /ˈpɒz.ɪks/[1]) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems.[1] POSIX defines both the system and user-level application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems.[1][2] POSIX is also a trademark of the IEEE.[1] POSIX is intended to be used by both application and system developers.[3]

https://en.wikipedia.org/wiki/POSIX

这个只是给了一个历史性的定义，还可以再多了解一些：👇

posix是什么都不知道，还好意思说你懂Linux？

Linux开发者越来越多，但是仍然有很多人整不明白POSIX是什么。本文就带着大家来了解一下到底什么是POSIX，了解他的历史和重要性。一、什么是posix？ 1. 概念POSIX：可移植操作系统接口（Portable Operating Syste…

https://zhuanlan.zhihu.com/p/392588996

所以可以回过来看NuttX的介绍：

Small Footprint

Rich Feature OS Set: The goal is to provide implementations of most standard POSIX OS interfaces to support a rich, multi-threaded development environment for deeply embedded processors.

NON-GOALS: It is not a goal to provide the level of OS features like those provided by Linux. In order to work with smaller MCUs, small footprint must be more important than an extensive feature set. But standard compliance is more important than small footprint. Surely a smaller RTOS could be produced by ignoring standards. Think of NuttX is a tiny Linux work-alike with a much reduced feature set.

Highly Scalable

Standards Compliance NuttX strives to achieve a high degree of standards compliance. The primary governing standards are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOS’s are adopted for functionality not available under these standards or for functionality that is not appropriate for the deeply-embedded RTOS (such as fork()).

Real-Time Fully pre-emptible; fixed priority, round-robin, and “sporadic” scheduling.

Totally Open Non-restrictive Apache license.

GNU Toolchains Compatible GNU toolchains based on buildroot available for download to provide a complete development environment for many architectures.