Learn how some of IBM's key cloud products play their part

Cloud computing is a model that provides web-based software, middleware, and computing resources on demand. By deploying technology as a service, users can access only the resources they need for their specific tasks, ultimately enabling them to achieve savings in investment costs, development time, and resource overhead. Enabling users to access the latest software and technology also drives Http://www.aliyun.com/zixun/aggregation/13686.html's "> Business innovation."

This series of articles will help you understand the concept and working principles of cloud computing and how IBM products can help you successfully implement your cloud strategy.

The first article introduces some of the technologies that make cloud computing possible, and then introduces the basics of cloud computing.

Inside the Cloud

Platform Virtualization

Platform virtualization refers to the logical decomposition of a physical machine into multiple virtual machines (VMS) or guest machines. The goal of platform virtualization is to consolidate resources, reduce space and energy costs, and separate operating systems from physical hardware to increase flexibility. Platform virtualization is typically done by a hypervisor, a software or firmware layer that supports other software (usually the operating system) running in parallel, just as the software can access a real machine. Virtual Machine hypervisor, also known as Virtual Machine Monitor (VMM), controls the physical resources of machines and displays them as virtual resources when used with VMS.

There are two types of hypervisor: The 1th type runs directly on the physical hardware, and the 2nd type requires a host operating system to run (see Figure 1).

Figure 1. Type of hypervisor

Examples of the 1th type of virtual machine hypervisor include IBM z/vm®, IBM powervm®, and VMWare esx/esxi Server for Windows®. Other examples include Citrix Xen and microsoft®hyper-v®. Because they run on the hardware itself, the 1th type of hypervisor is also known as a native or bare-metal virtual machine hypervisor.

Examples of the 2nd type of virtual machine hypervisor include VMware Workstation, VMware Server, kernel-based Virtual Machine (KVM), and ORACLE®VM VirtualBox. The 2nd type of virtual machine hypervisor is also known as a hosted virtual machine management program. For some virtual machine management programs (such as KVM), whether they should be classified as type 1th or 2nd, and the way in which they are categorized is meaningful to the way they work, there is still a lot of controversy that is not covered by this article.

Figure 2 briefly describes the virtual machine management programs that are currently supported by IBM Hardware and IBM Cloud solutions.

Figure 2. Virtual machine management programs currently supported on IBM hardware

VMS have different names because of the specific platform. A virtual machine in a aix® environment is called a logical partition or an LPAR. On a x86 based system, the vocabulary used is a virtual machine. The VM system uses two different names: LPAR and VM. The Lpar in VM is a hardware resource block that is essentially allocated in the system z® computer, and each lpar can support a separate operating system, one of which is the VM itself. So, a VM LPAR can host a VM guest, which in turn can host different VMs. A hardware tool in the System Z computer can create and manage LPARs in the same way that VM creates and manages VMS. This operating system is called Zlinux Guest or Zlinux VM when you have an linux® guest operating system running on IBM VM.

Virtualization is not new. IBM developed the technology for the first time in the 60 's to multiplex its expensive mainframe computers. After extensive research and implementation of the CP-40/CMS and Cp-67/cmd operating systems, IBM s/360-67, the first fully virtualized machine, came out in 1967. By 1972, virtual machines have become a standard feature of all s/370 mainframes. s/370 runs IBM's vm/370 operating system, which was once a time-sharing system control program, and eventually evolved to VM. Today, virtualization is pervasive in a variety of data centers and cloud environments and is one of the key technologies that make cloud computing work.