Most operating systems—and Linux is no exception to this rule—can be used in a variety of ways. You can run Linux (or Windows, or Mac OS, or most other common general-purposes OSs) on personal productivity desktop systems, on mail server computers, on routers, and so on. This book doesn’t cover every possible use of Linux; instead, it focuses on how Linux interacts with Windows systems on a local area network (LAN) or how Linux can take over traditional Windows duties. This book will further focus on areas in which you can get the most “bang for the buck” by deploying Linux, either in addition to or instead of Windows systems. Chapter 2 covers Linux deployment strategies in greater detail, but, for now, consider Figure 1-1, which depicts a typical office network. Linux’s mascot is a penguin (known as Tux), so Figure 1-1 uses penguin images to mark the areas of Linux deployment covered in this book.

Figure 1-1. The uses for Linux described in this book

Of course, Linux can be used in roles not shown in Figure 1-1. In fact, Linux can be an excellent choice for an OS for such roles as a web server; however, because such uses aren’t LAN-centric or don’t tie closely to Windows, this book doesn’t cover them. You might want to begin with just one or two functions for Linux on your network, such as a file server or a Dynamic Host Configuration Protocol (DHCP) server. Some systems, such as backend database servers, may be so vital and data-intensive that replacing them with Linux systems, although possible, is a major undertaking that can’t be adequately covered here.