Server Core? Is that like an apple (or Apple, natch) core? It depends on how you look at it, really: in the context of this book, it's Microsoft's great new addition to the Longhorn Server product. Essentially, Server Core is a slimmed-down, appliance-like version of Longhorn Server that functions in a couple of limited roles and does nothing else.
Server Core, as I see it, has two main advantages: it's extremely focused, which means it does what it does very well, resulting in better performance, resilience, and robustness than a full-fledged operating system. It also has limited dependencies on other pieces of the Windows puzzle, in that the Core is designed to work without a lot of other software installed; it can generally work by itself. In comparison, many of the previous Windows components aren't really necessary—like Windows Explorer or Internet Explorer, for example—which is something that can't be said for Windows Server 2003.
All of this translates into a far smaller attack surface than the standard Windows Server product, given all of the material that's been stripped out. But there are some aspects of Server Core with which you might not yet be familiar, as well as some interesting facts and limitations of the "core"-based approach to computing. We'll take a look at them here.
This is probably the most unsettling but, upon reflection, most interesting and welcome difference between Server Core and the traditional Windows server operating system. When you boot Server Core, you'll get a colored screen that looks like a single-color desktop, which might fool you into thinking that you installed the wrong version. But you'll quickly be corrected as you get a command-prompt window; when it appears, all activity stops. It looks a lot like regular Windows if you open Task Manager and kill the explorer.exe process. Figure 9-1 shows this.
Figure 9-1. The default environment when a user logs on interactively to a Server Core-based machine
Indeed, you can open Notepad—just about the only graphical application installed—but you can open it only from the command line, and you can't save as another file; there is no support for displaying those sorts of Explorer windows. In fact, those windows are generated by code called a "shim," which is essentially a programming stub that allows Notepad to display these Explorer-related dialog boxes without tying into Explorer itself.
Essentially, you'll need to think back to your DOS days to get accustomed to administering Server Core. The command line is very, very powerful—in many instances you can accomplish more with commands, options, and switches than you can with the GUI—but it can be intimidating to start.
Here are some other things you don't get with Windows Server 2008 Server Core: