You will need a modern desktop PC or laptop. Ubuntu Desktop specifies the following as "recommended system requirements" for the installation and usage of the distribution:
- A 2 GHz dual core processor or better.
- RAM:
- Running on physical host: 2 GB or more system memory (more will certainly help).
- Running as a guest VM: The host system should have at least 4 GB RAM (the more the better and the smoother the experience).
- 25 GB of free hard drive space (I suggest more, at least double this).
- Either a DVD drive or a USB port for the installer media (not required when setting up Ubuntu as a guest VM).
- Internet access is definitely helpful and required at times.
As performing tasks such as building a Linux kernel from source is a very memory- and CPU-intensive process, I highly recommend that you try it out on a powerful Linux system with plenty of RAM and disk space to spare as well. It should be pretty obvious – the more RAM and CPU power the host system has, the better!
Like any seasoned kernel contributor, I would say that working on a native Linux system is best. However, for the purposes of this book, we cannot assume that you will always have a dedicated native Linux box available to you. So, we will assume that you are working on a Linux guest. Working within a guest VM also adds an additional layer of isolation and thus safety.
Cloning our code repository: The complete source code for this book is freely available on GitHub at https://github.com/PacktPublishing/Linux-Kernel-Programming. You can clone and work on it by cloning the git tree, like so:
git clone https://github.com/PacktPublishing/Linux-Kernel-Programming.git
The source code is organized chapter-wise. Each chapter is represented as a directory – for example, ch1/ has the source code for this chapter. The root of the source tree has some code that is common to all chapters, such as the source files convenient.h, klib_llkd.c, as well as others.
For efficient code browsing, I would strongly recommend that you always index the code base with ctags(1) and/or cscope(1). For example, to set up the ctags index, just cd to the root of the source tree and type ctags -R .
Unless noted otherwise, the code output we show in the book is the output as seen on an x86-64 Ubuntu 18.04.3 LTS guest VM (running under Oracle VirtualBox 6.1). You should realize that due to (usually minor) distribution – and even within the same distributions but differing versions – differences, the output shown here may not perfectly match what you see on your Linux system.