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CHAPTER 1 WINDOWS SERVER 2008 ARCHITECTURE
When DEC canceled the PRISM project in 1988, Microsoft was able to hire away many of the
team members working in DEC West in Seattle. Systems architect David Cutler, who had experi-
ence with Virtual Memory System (VMS) and Reduced Instruction Set Computer (RISC) architec-
ture, became the head of the development team that rewrote the Microsoft version of OS/2. The
concepts of a microkernel, protective mode, an executive program, device drivers, and hardware
abstraction all arise from the work of Cutler’s group and the heritage that they brought to Microsoft.
The basic idea behind Windows Server was that Microsoft (being a software company) should cre-
ate an operating system that was portable from one hardware platform to another with a straight-
forward recompile.
The original NT project targeted development of IA-32 (Intel Architecture), MIPS (Microprocessor
without Interlocked Pipeline Stages), Alpha, PowerPC, SPARC, and Intel i860 and i960. Microsoft
released the first version of NT on July 27, 1993. Indeed, the multiplatform heritage of Windows
Server is supposedly the origin of the NT name, as initial development of OS/2 3.0 was for the i860
processor code named N10, or “N-Ten.” It is speculated, but not confirmed, that Microsoft replaced
the NT name (which they marketed under “New Technology”) with the year designations because
of a trademark issue with Nortel Networks, whose Northern Telecom owns the NT trademark.
Today the Windows operating systems in general, and the Windows Server systems specifi-
cally, owe much of their success and many of their shortcomings to the design decisions made by
the original NT team for Windows NT. There isn’t space here to expound on why many of the tech-
nical features in Windows are a little goofy (you can take the Windows Registry as an example), but
any reader interested in software history from a technical viewpoint should take a look at Raymond
Chen’s The Old New Thing: Practical Development Throughout the Evolution of Windows (2006).
System Overview
Windows Server is an example of a preemptive, multitasked, multithreaded operating system. The
term preemptive means that the Windows operating system can switch the order of tasks held in
memory based on a set of scheduling policies and priorities, a process commonly referred to as con-
text switching. Windows can perform a context switch because it recognizes that a process has
ended, that a process is blocked by a shared resource, or that the process has been switched to
another processor. This behavior (which is a software version of a system interrupt) is performed
by the kernel, and is different from a system in which tasks are scheduled through time sharing or
through a system of hardware interrupts. There are many advantages to preemption, but the most
important are that preemption uses resources more efficiently and that it can remove many instances
of processes that are either CPU bound or input/output (I/O) bound, waiting for other processes
to finish.
A process or task is the execution of program or service. You can see processes executing in
Windows Server 2008 or Vista in the Task Manager, where the consumption of memory and CPU
is given for each. Figure 1.1 shows the Process page of the Task Manager.
Although the Task Manager got an upgrade in Vista so that it shows more information and actu-
ally describes what each process is, it does not offer the most complete description you can get on
your system. That honor belongs to the service- and process-related commands you can enter into
PowerShell, which is discussed in Chapter 8, “PowerShell.”
You can get to the Task Manager by doing any of the following:
◆
Right click the Taskbar and select the Task Manager from the context menu.
◆
Click an empty area of the desktop and press Ctrl+Shift+Esc.
◆ Click the Start menu, enter TASKMGR into the Search text box, then press the Enter key.
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