This document defines the platform and system requirements for designing LoPAR platforms. This document is the primary source of information that a platform, OS, or hardware component developer would need to create compatible products. Additional requirements are defined by the industry standards referenced in this document. This document describes the platform to OS interface which must be provided in these platforms. Platform designers must assemble components and firmware which match this interface. Also, the document defines minimum system configuration requirements. Platform designers must meet or exceed these minimums to build a standard platform. This document must be used by those designing compatible software including the OS, boot software, or firmware. If a function is supported, software developers must provide support for the interfaces described in this document. This software must provide the mandatory functions and capabilities as described in the requirements in this document. However, this document does not limit this software from going beyond the specification through software tailored to specific hardware. For example, the OS must implement the interface to the required abstracted interfaces to hardware, but the OS may also implement fast paths to specific hardware that it recognizes.