Virtualization allows for the creation of virtual machines that emulate dedicated hardware. A hypervisor software allows multiple virtual machines to run isolated operating systems like Linux and Windows on the same physical host. This improves hardware utilization and lowers costs by reducing physical servers and maintenance. There are two main types of virtual machines - process virtual machines that virtualize individual processes, and system virtual machines that provide a full virtualized environment including OS and processes. Virtualization provides benefits like better hardware usage, isolation, manageability and lower costs.

1. Virtualization

2. Introduction to Virtual machines
• A virtual machine (VM) is an operating system (OS) or application environment
that is installed on software, which imitates dedicated hardware. The end user has
the same experience on a virtual machine as they would have on dedicated
hardware.
• Specialized software, called a hypervisor, emulates the PC client or server's CPU,
memory, hard disk, network and other hardware resources completely, enabling
virtual machines to share the resources.
• The hypervisor can emulate multiple virtual hardware platforms that are isolated
from each other, allowing virtual machines to run Linux and Windows Server
operating systems on the same underlying physical host.
• Virtualization limits costs by reducing the need for physical hardware systems.
Virtual machines more efficiently use hardware, which lowers the quantities of
hardware and associated maintenance costs, and reduces power and cooling
demand.

3. Types of Virtual machines
• Process Virtual Machine
• System Virtual Machine

4. Process Virtual Machines
Virtualizing software translates a set of OS and user-level
instructions composing one platform to another, forming a
process virtual machine capable of executing programs
developed for a different OS.

5. Continued …
• Supporting individual processes
• Virtualization software is placed over the
ABI(Application Binary Interface)
• Host – underlying platform
• Guest – software in VM
• Native – platform in the VM
• Virtualizing software – runtime that supports the
guess process and runs on top of operating system.

6. System VM
• Provides a complete system environment.
• Supports an operating system along with its
potentially many user processes.
• Provides a guest operating system with
access to underlying hardware resources,
including networking, I/O, a display and
graphical user interface.

7. Continued …

10. • The term virtualization broadly describes the
separation of a resource or request for a
service from the underlying physical entity.
• Virtualization lets a single physical resource
(such as server, OS, application or storage
device) appear as multiple logical resources;
or making multiple physical resources (such as
storage devices or servers) appear as a single
logical resource.

12. Types of Virtualization
• Hardware
– Full virtualization
– Para virtualization
• Desktop
• Storage
• Network

13. Full virtualization
• Virtual machine talks to VMM which communicates
with the hardware platform
• CPU understands the unmodified instructions
generated by Virtualized OS
• Advantages
– Complete decoupling of the software from the hardware
– Complete isolation of different applications
• Disadvantages
– VMM should provide additionally virtual bios, virtual
memory space and virtual devices
– VMM creates and maintains data structures like shadow
memory page table

14. Full Virtualization

15. Para virtualization
• Guest OS uses specialized API that talks to the VMM
which sends the virtualization requests to the
hardware
• VMM does not need a resource intensive
translation of instructions
• Advantages
– near native performance
– migration
• Disadvantages
– not applicable for Windows OS

16. Para Virtualization

17. Desktop Virtualization
• Defines the concept of separating logical
desktop from physical machine.
• Virtual desktop infrastructure
• Session Virtualization
• Thin clients

18. Network Virtualization
• Creation of virtualized network addressing
space within or across network subnets
• Grouped into two
– External Network Virtualization- VLANs ,VPNs
– Internal Network Virtualization-Single host with
Virtual Routing Tables

19. Storage virtualization
• Storage virtualization is the process of
completely abstracting logical storage from
physical storage
• Classified into 2 types
– Block [SAN ]
– File
• Technology
– iSCSI ( Internet Small Computer Systems Interface)
– RAID 0,1,5,6

20. Benefits of virtualization
• Fully utilize hardware resources
• Running heterogeneous environments
• Isolation
• Manageability
• Reduced Power requirements
• Reduced ownership cost