Datasheet

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CHAPTER 1 WINDOWS SERVER 2008 ARCHITECTURE
that would mean any or all of the following: different versions of Windows or DOS, Linux,
NetWare, Solaris for x86, and maybe one day Macintosh. The Macintosh’s Boot Camp utility allows
you to run Windows on a Macintosh in a virtual machine on x86 today; an even better solution
exists with Parallels ( http://www.parallels.com/ ). You can find a rather extensive table comparing
different virtual machine technologies at
http://en.wikipedia.org/wiki/Comparison_of_virtual_machines
Be forewarned that this is an area of great activity, so the list is volatile and subject to change.
A hypervisor controls an entire computer system. Hypervisors have been around for quite some
time in various forms, and they are one of the favorite methods hackers use to take full control over
systems. Indeed, Microsoft’s hypervisor technology (which is now called Microsoft Hyper-V and is
available as an option for Windows Server 2008) will probably make it impossible for competitors to
gain this type of access in the future. A hypervisor can run two or more operating systems on:
◆
The same processor
◆
Different cores of a multicore processor
◆
Different cores on different single or multicore processors
There are actually two types of hypervisors, and each has some limits on its capabilities:
Type 1 Hypervisor This is a lightweight operating system that runs in a layer that loads over
hardware and below the operating system that the hypervisor “hosts.” The hypervisor boots the
system and receives privileged access to Ring 0 and other low-level services. The first Type 1
hypervisor was probably IBM’s CP/CMS system; IBM still uses the technology with their z/VM
OS product. Other Type 1 hypervisors are VMware’s ESX Server and Sun Microsystems’ Logical
Domains hypervisor, which was introduced in 2005. Figure 1.7 shows a Type 1 hypervisor.
Figure 1.7
Type 1 Hypervisor
Type 2 Hypervisor Windows Server 2008 virtualization programs use a different type of
hypervisor, referred to as a Type 2 hypervisor or Type 2 virtual machine, as shown in Figure 1.8.
This type of program runs after the operating system has been loaded, and the guest operating
system runs “on top of” or using the services of the hypervisor. The two most popular virtual-
ization products in the world are probably VMware ( http://www.vmware.com ), which is now
owned by EMC, and Virtual PC, which was acquired by Microsoft from Connectix. VMware is
Application
Operating
System
Application
Operating
System
Application
Operating
System
Hypervisor
Operating System
SMP Server
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