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Embedded linux system development based on Yocto
1. Introduction to yocto
The Yocto Project is not a single open source project but represents what is developed and maintained under its umbrella 完整项目家族.
Several points for customizing the linux distribution:
Let's face it—building and maintaining an operating system is no simple task. Many different aspects of an operating system need to be considered to create a fully functional computer system.
引导加载程序(Bootloader): The bootloader is the first piece of software that is responsible for initializing the hardware, loading the operating system kernel into memory and then starting the kernel. The bootloader is usually multi-level, and its first level is stored in non-volatile memory. The first level then loads the second level from the mounted storage (eg flash, hard disk). and so on.
内核：The kernel, as its name suggests, is the heart of the operating system. It manages the hardware resources of the system and provides hardware abstraction to other software through its application programming interface. 内核的主要功能是内存管理、 设备管理和响应来自应用软件的系统调用. How these functions are implemented depends on the processor architecture and peripherals and other hardware configurations.
设备驱动: Device drivers are part of the kernel. They provide access to hardware devices in structured software through kernel system calls. Through device drivers, application software can configure the hardware, get data from the hardware, or write data to the hardware.
生命周期管理(Life Cycle Management): From power-on to power-off, a computer system assumes multiple states in which it provides different sets of services to application software. Lifecycle management determines what services are running in what state and in what order they need to be started to maintain a consistent operating environment. An important part of lifecycle management is also power management, setting the system into power-saving mode when full functionality is not needed, and returning to full operating mode when requested.
应用软件管理: Applications and libraries make up the majority of software installed on a typical system, providing functionality to most users. For a complete operating system, it usually requires hundreds to thousands of software packages.
Yocto Project Strengths:
This is where the Yocto Project strengths lie. It combines the best of both approaches by giving you a complete toolset and blueprint to help you create your own Linux distribution from scratch (starting with a source code download from an upstream project). Blueprints for various systems that come with the Yocto Project tools allow you to 在几个小时内构建完整的操作系统栈.
2. Simple use of yocto
The full name of Yocto is Yocto Project (officially referred to as YP), which is an open source collaborative project launched by the Linux Foundation in 2010. 提供模板、工具和方法以创建定制的 Linux 系统和配套工具, without having to care about the hardware system. It mainly consists of Poky and some other tools.
Historically, the Yocto Project grew out of the OpenEmbedded project. They were originally two different projects (separated view on the left), however, the current OpenEmbedded and Yocto Project have been merged into one (merged view on the right), because it is rare to use OpenEmbedded alone.