GLYPH<SM590000> IT flexibility and responsiveness GLYPH<SM590000> IBM PR/SM™ is the facility on LinuxONE servers that provides another layer of  virtualization. It is a hypervisor that is classified as type 1 and allows multiple LPARs to  share physical resources, such as processors, memory, channel paths, and DASDs. GLYPH<SM590000> Dynamic Partition Manager (DPM) is a new administrative mode that was introduced to  LinuxONE servers. A system can be configured in DPM mode or PR/SM mode. The mode  is enabled before system power-on reset (POR). –F a s t – Easy  –P o w e r f u l Virtualization enables clients to have a single, consolidated view of, and easy access to, all  available resources in the network, regardless of location. It also enables clients to reduce  the management of their environment by providing emulation for compatibility, improved  interoperability, and transparent change windows. By adding any of these virtualization technologies to your environment, you create an  on-demand, secure, and flexible infrastructure that is prepared to handle workload changes in  your environment. IBM virtualization is the answer for the Cloud because it perfectly adheres  to the hardware server and uses the LinuxONE functionalities with efficiency, high throughput,  and security that is inherent of this platform.  The following facilities are available in LinuxONE servers and are used to divide the hardware  into LPARs. They are classified as type 1 hypervisors, are run directly on the hardware, and  are known as “native” or “bare metal”: DPM provides the following advantages: Much faster than managing with HCD and HCM (from hours to minutes). Intuitive user interface. No need for multiple administrators with different skills or tools.  The same efficient PR/SM hardware virtualization, without the complexity. It supports  dynamic configuration changes with just a few mouse clicks. It provides a foundation  for “bare metal” cloud. z/VM is the mature virtualization solution of IBM. It is reliable and flexible, and shares the  resources to support thousand of guest servers with a high performance. As a hypervisor  operating system, its security does not differ from the security of any other operating system  on a server. However, the virtual infrastructure relies on the security of the hypervisor, so  protecting the z/VM hypervisor often prevents attempts to breach the security of the operating  system and compromises to the integrity of the operating system and data.  The merger of z/VM and Linux on LinuxONE is perfect because z/VM can have hundreds of  Linux servers that are running harmoniously while z/VM manages all of the resources of the  LPAR with the benefit of improved price performance as workloads grow. 3.2 z/VM hypervisor and LinuxONE servers 3.1.2 Hardware virtualization Chapter 3. IBM z/VM hypervisor  27