Method and apparatus for switching tasks

摘要

A multitasking system is arranged so that task switching can be performed efficiently in a short time. Resources usable by tasks are controlled in a state of being separated into a plurality of resource groups. When one of the tasks which has become active by task switching uses one of the resources, ascertainment is made as to whether the resource group to which the resource required by the task belongs is usable. If the resource group is usable by the active task, the active task is permitted to use the resource to advance its process. If the resource group is not usable by the task, the conditions relating to the resource group to which the required resource belongs are changed so that the task can use the resource group. Thereafter, the active task is permitted to use the resource to advance its process.