Patent ID: 8291425
Filing Date: 2012-10-16
Classification: G06F

Abstract:
1. A computer in which functions of its resources including a processing unit and memory are divided to realize a plurality of virtual computers and which includes a plurality of physical devices that are peripheral connecting devices or network connecting devices, the computer comprising: a managing unit that includes the processing unit and the memory, manages the plurality of virtual computers and the plurality of physical devices, assigns the virtual computers the physical devices so as to function as virtual devices, and manages the virtual devices according to one of a plurality of control schemes including a dedicated scheme where a virtual device is associated with a physical device on a one-to-one basis and a shared scheme where plural virtual devices are associated with one physical device, wherein the managing unit has: status information holding use-status information indicating either an active status where the virtual device is in use or an inactive status where the virtual device is hardly or not at all in use; configuration information holding information about configurations including respective address spaces of the physical devices and the virtual devices; and association information holding information about association between the physical devices and the virtual devices, and wherein the managing unit refers to the status information and, when determining that usage of the virtual device has changed from an active usage to a standby usage or from the standby usage to the active usage, referring to the configuration information and the association information, searches for a physical device compatible with a control scheme of the virtual device, determines whether or not there is a physical device compatible with the virtual device among the searched physical devices based on at least one of a hardware specification, an identifier, and an address space, and when there are one or more physical devices compatible with the virtual device, when there is not any physical device compatible with the virtual device, wherein there are two types of the dedicated scheme, including a direct dedicated scheme where commands issued from the virtual computer to the virtual device can be directly transmitted to the associated physical device, and an indirect dedicated scheme where the managing unit translates commands issued from the virtual computer to the virtual device in terms of address and transmits the translated commands to the associated physical device.