Chapter 9. Wic and Other Tools

In this chapter, you will be given a brief introduction to a number of tools that address various problems and solves them in ingenious ways. This chapter can be thought of as an appetizer for you. If any of the tools presented here seem to interest you, I encourage you to feed your curiosity and try to find more about that particular tool. Of course, this piece of advice applies to any information presented in this book. However, this bit of advice holds true particularly for this chapter because I've chosen a more general description for the tools I've presented. I've done this as I've assumed that some of you may not be interested in lengthy descriptions and would only want to focus your interest in the development process, rather than in other areas. For the rest of you who are interested in finding out more about other key areas, please feel free to go through the extensions of information available throughout the chapter.

In this chapter, a more detailed...

Swabber

Swabber is a project, which although is presented on Yocto Project's official page, is said to be a work in progress; no activity has been done on it since September 18, 2011. It does not have a maintainers file where you can find more information about its creators. However, the committers list should be enough for anyone interested in taking a deeper look at this project.

This tool was selected for a short introduction in this chapter because it constitutes another point of view of the Yocto Project's ecosystem. Of course, a mechanism for access detection into the host system is not a bad idea and is very useful to detect accesses that could be problematic for your system, but it is not the first tool that comes to mind when developing software. When you have the possibility of redoing your build and inspecting your host ecosystem manually, you tend to lose sight of the fact that tools could be available for this task too, and that they could make your life easier.

For interaction...

Wic

Wic is a command line tool that can be also seen as an extension of the BitBake build system. It was developed due to the need of having a partitioning mechanism and a description language. As it can be concluded easily, BitBake lacks in these areas and although initiatives were taken to make sure that such a functionality would be available inside the BitBake build system, this was only possible to an extent; for more complex tasks, Wic can be an alternative solution.

In the following lines, I will try to describe the problem associated with BitBake's lack of functionality and how Wic can solve this problem in an easy manner. I will also show you how this tool was born and what source of inspiration source was.

When an image is being built using BitBake, the work is done inside an image recipe that inherits image.bbclass for a description of its functionality. Inside this class, the do_rootfs() task is the one that the OS responsible for the creation of the root filesystem directory that...

LAVA

LAVA (Linaro Automation and Validation Architecture) is a continuous integration system that concentrates on a physical target or virtual hardware deployment where a series of tests are executed. The executed tests are of a large variety from the simplest ones which only requires booting a target to some very complex scenarios that require external hardware interaction.

LAVA represents a collection of components that are used for automated validation. The main idea behind the LAVA stack is to create a quality controlled testing and automation environment that is suitable for projects of all sizes. For a closer look at a LAVA instance, the reader could inspect an already created one, the official production instance of which is hosted by Linaro in Cambridge. You can access it at https://validation.linaro.org/. I hope you enjoy working with it.

The LAVA framework offers support for the following functionalities:

• It supports scheduled automatic testing for multiple packages on various hardware...

Summary

In this chapter, you were presented a new set of tools. I will honestly admit that these tools are not the ones used most often in an embedded environment, but they've been introduced in order to offer another point of view to the embedded development environment. This chapter tried to explain to developers that there is more to the embedded world then just development and the tools that help with these tasks. In most cases, the adjacent components are the ones that could inspire and influence the development process the most.

In the next chapter, a short presentation of the Linux real-time requirements and solutions will be presented. We will emphasize the various features that work alongside Linux in this area. A short presentation of the meta-realtime layer will be offered, and features, such as Preempt-RT and NOHZ, will be discussed. Without further ado, let's proceed to the next chapter. I hope you will enjoy its content.