Virtualization is a framework or methodology of
dividing the resources of a computer into multiple
It can also be explicate as an abstraction layer that
decouples the physical hardware from the operating
system to deliver greater IT resource utilization &
It is done by applying one or more concepts or
technologies such as:
Partial or complete machine simulation,
Hardware & software partitioning,
Quality of service,
And many others. . .
Virtualization technology enables multiple operating
systems and application ‘images’ to share a single
A virtual server, or what is commonly known as a
‘virtual machine’, simulates the operations of your
This enables an application to run on a machine as it
would on a physical server.
Its NOT A NEW CONCEPT
1960’s at IBM:
M44/44X Project - the goal of which was being to evaluate
the then emerging time sharing system concepts.
The architecture was based on virtual machines:
The main machine was an IBM 7044(M44) and each virtual
machine was an experimental image of the main
IBM & MIT headed research through the years & eventually
developed the idea of a virtual Machine Monitor(VMM).
The VMware virtualization platform is built on a BUSINESS-
Use software such as VMware vSphere to transform or
“virtualized” the hardware resources of an x86-based computer—
including the CPU, RAM, hard disk and network controller—to
create a fully functional VIRTUAL MACHINE that can run its own
operating system and applications just like a “real” computer.
Each virtual machine contains a complete system, eliminating
potential conflicts. It works by inserting a thin layer of software
directly on the computer hardware or on a host operating system.
This contains a virtual machine monitor or “hypervisor” that
allocates hardware resources dynamically and transparently.
Multiple operating systems run concurrently on a single
physical computer and share hardware resources with each
By encapsulating an entire machine, including CPU, memory,
operating system, and network devices, a virtual machine is
completely compatible with all standard x86 operating
systems, applications, and device drivers.
We can safely run several operating systems and applications
at the same time on a single computer, with each having
access to the resources it needs when it needs them.
approach to x86
approach to x86
The hardware assist
approach to x86
Modern computer systems are composed of various hardware
& software layers.
Virtualization inserts a software layer(VMM) at different
points in this architecture, comes in three variants:
High-level language virtual
Virtualization layer sits right on top of the real hardware.
Since the VM presents a version the real machine, all software
written for that hardware(x86) will run on that virtual
Original design from IBM in the 1960’s
Virtualization layer sit between the operating system and the
application programs that run on the operating system
Virtual Machine runs applications, or sets of applications
written for the operating system but in a controlled
use host OS API
FreeBSD jails act like this.
The virtualization layer sits
as an application program
on top of the operating
Can run any programs
written for that virtual
regardless of the operating
system hosting that virtual
machine Real Machine
Java Byte Code
It enables us to get the most out of our server hardware.
It will allow us to set up redundant servers for better fault
Management is simplified.
We can partition applications on separate OSes for greater
Provisioning new servers for prototyping, testing and
migration is simplified.
We can save energy.
Virtual Desktop Infrastructure can save us a fortune on PCs
Microsoft Virtual Server
Microsoft Virtual PC
Hardware companies have taken notice of virtualizations
growing popularity and advantages
Intel (called Virtualization Technology or VT-X Vander pool)
and AMD (Pacifica) are releasing processors that have built in
software virtualization support that try to eliminate emulation
This support will allow Xen to support unmodified
unprivileged OS’s (hello Windows support)
Many organizations across Australia are starting to take
advantage of server virtualization to reduce power, cooling
and equipment costs, reduce server administration and
downtime, and gain a higher level of server redundancy.