DPM provides facilities to define and run virtualized computing systems by using a  firmware-managed environment that coordinate the physical system resources that are  shared by the partitions. The partitions’ resources include processors, memory, network,  storage, crypto, and accelerators.  DPM provides a new mode of operation for IBM Z servers that provide the following services: DPM is not another hypervisor for IBM Z servers. DPM uses the PR/SM hypervisor  infrastructure and provides an intelligent interface on top of it that allows customers to define,  use, and operate the platform virtualization without IBM Z experience or skills. In z15 servers, memory can be assigned as main storage, supporting up to 85 LPARs. Before  you activate an LPAR, main storage must be defined to the LPAR. All installed storage can be  configured as main storage. Each z/OS individual LPAR can be defined with a maximum of  4 TB of main storage. z/VM V6R4 and z/VM V7R1 support 2 TB of main storage. Memory  cannot  be shared between system images (LPARs). It is possible to dynamically  reallocate storage resources for z/Architecture LPARs that run operating systems that support  dynamic storage reconfiguration (DSR). This process is supported by z/OS, and z/VM. z/VM,  in turn, virtualizes this support to its guests. For more information, see 3.7.5, “LPAR dynamic  storage reconfiguration” on page 142. Operating systems that run as guests of z/VM can use the z/VM capability of implementing  virtual memory to guest virtual machines. The z/VM dedicated real storage can be shared  between guest operating systems. The z15 storage allocation and usage possibilities, depending on the image mode, are listed  in Table 3-8. a. z/VM mode is supported by z/VM V6R4 and later. b. Secure Service Container Table 3-8 Main storage definition 3.7.2 Storage operations GLYPH<SM590000> Facilitates defining, configuring, and operating PR/SM LPARs in a similar way to how  someone performs these tasks on another platform. GLYPH<SM590000> Lays the foundation for a general IBM Z new user experience. Chapter 3. Central processor complex design  139 Image mode Architecture mode (addressability) Maximum main storage Architecture z15 definition General  z/Architecture (64-bit) 16 EB 4 TB Coupling facility CFCC (64-bit) 1.5 TB 1 TB Linux only z/Architecture (64-bit) 16 EB 16 TB z/VM a z/Architecture (64-bit) 16 EB 2 TB SSC b z/Architecture (64-bit) 16 EB 16 TB