What is system programming?

When we talk about what system programming is, we can start with the definition of system programming in Wikipedia:

"System programming (or systems programming) is the activity of programming system software. The primary distinguishing characteristic of systems programming when compared to application programming is that application programming aims to produce software which provides services to the user (e.g. word processor), whereas systems programming aims to produce software and software platforms which provide services to other software, are performance constrained, or both (e.g. operating systems, computational science applications, game engines and AAA video games, industrial automation, and software as a service applications). "

From the preceding definition, we can see that when we talk about system programming we actually deal with the building blocks of the computer system itself. We may depict the system architecture and how it looks like inside the system. As an example, we can refer to system programming books for Windows or Linux. The book Linux System Programming published by O'Reilly Media, Inc. includes topics about file I/O, process management, memory management, interrupt handling, and so on. There is another book called Windows System Programming published by Addison-Wesley Professional that includes very similar topics to its Linux counterpart.

You may expect similar content in this book for Android, but you will find that the topics in this book are quite different from the classic system programming book. First of all, it doesn't really make sense to have a system programming book for Android talk about file I/O, process management, or memory management, because the Linux System Programming book can cover almost the same topics for Android (Android uses Linux kernels and device driver models).

When you want to explore kernel space system programming, you can read books such as Linux Device Drivers by O'Reilly or Essential Linux Device Drivers from Prentice Hall. When you want to explore user space system programming, you can read the book that I mentioned before, Linux System Programming by O'Reilly. Then you may wonder, Do we need an Android System Programming book in this case? To answer this question, it depends on how we look at system programming for Android. Or in other words, it depends on which angle we look at Android System Programming from. We can tell people different things about the same world from different perspectives. In that sense, we may need more than one book to talk about Android system programming.

To talk about Android system programming, we can talk about it theoretically or practically. In this book, we will do it practically with a few actual projects and hands-on examples. Our focus will be how to customize the Android system and how to port it to a new platform.