What are hardware level virtualization?

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  •  It is a virtualization technique that provides an abstract execution environment in terms of computer hardware on top of which a guest OS can be run. It is also called system virtualization.


Hypervisor 

  • The hypervisor runs above the supervisor mode.
  • It runs in supervisor mode. 
  • It recreates a h/w environment.
  • It is a piece of s/w that enables us to run one or more VMs on a physical server(host).
  • Two major types of hypervisors – Type -I & Type-II

Type-I Hypervisor 

  • It runs directly on top of the hardware. 
  • Takes place of OS. 
  • Directly interact with the ISA exposed by the underlying hardware. Also known as a native virtual machine.



Type-II Hypervisor

  • It requires the support of an operating system to provide virtualization services. 
  • Programs are managed by the OS. 
  • Emulate the ISA of virtual h/w. Also called hosted virtual machine.



 Hardware Virtualization 

  •  In the case of virtual storage, the guest might be client applications or users that interact with the virtual storage management software deployed on top of the real storage system. The guest applications and users interact with a virtual network, such as a virtual private network (VPN), which is managed by specific software (VPN client) using the physical network available on the node. VPNs are useful for creating the illusion of being within a different physical network and thus accessing the resources in it, which would otherwise not be available. 
  • Here in Hardware Virtualization Guest is represented by a system image which is comprised of an operating system and installed applications. These are installed on top of virtual hardware that is controlled and managed by the virtualization layer, also called the virtual machine manager. The host is instead represented by the physical hardware and in some cases the operating system, which defines the environment where the virtual machine manager is running.


 Hardware Level Virtualization 

Hardware-level virtualization is a virtualization technique that provides an abstract execution environment in terms of computer hardware on top of which a guest operating system can be run. In this model, the guest is represented by the operating system, the host by the physical computer hardware, the virtual machine by its emulation, and the virtual machine manager by the hypervisor. The hypervisor is generally a program or a combination of software and hardware that allows the abstraction of the underlying physical hardware. Hardware-level virtualization is also called system virtualization,

 Hypervisors

 A hypervisor is a form of virtualization software used in Cloud hosting to divide and allocate the resources on various pieces of hardware. The program which provides partitioning, isolation, or abstraction is called a virtualization hypervisor. The hypervisor is a hardware virtualization technique that allows multiple guest operating systems (OS) to run on a single host system at the same time. A hypervisor is sometimes also called a virtual machine manager(VMM).

 Types of Hypervisors

 TYPE-1 Hypervisor: 

The hypervisor runs directly on the underlying host system. It is also known as a “Native Hypervisor” or “Bare metal hypervisor”. It does not require any base server operating system. It has direct access to hardware resources. Examples of Type 1 hypervisors include VMware ESXi, Citrix XenServer, and Microsoft Hyper-V hypervisor.



 TYPE-2 Hypervisor:

 A Host operating system runs on the underlying host system. It is also known as ‘Hosted Hypervisor”. Basically, software installed on an operating system. The hypervisor asks the operating system to make hardware calls. Examples of Type 2 hypervisors include VMware Player or Parallels Desktop. Hosted hypervisors are often found on endpoints like PCs.


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