1. For use in a computer system having a scalar processor, a vector processor, a plurality of operating systems, and a virtual environment for running the plurality of operating systems on the scalar processor as virtual machines under control of a virtual machine monitor, a virtual environment operating method, comprising the steps of: running the operating systems selectively on the scalar processor as virtual machines to share the scalar processor with the operating systems; controlling said vector processor and said scalar processor, for assigning vector processing tasks from any of said virtual machines to said vector processor for sharing the vector processor among the operating systems running on said scalar processor; running a first operating system on the scalar processor so that said running of the first operating system on the scalar processor thereby requests the vector processor to execute a first vector processing job; sending a notice of vector processing end by the vector processor to the first operating system and intercepting the notice of the vector processing end by the virtual machine monitor; wherein said intercepting includes setting an interception flag; and thereafter running the first operating system on the scalar processor, checking the interception flag and receiving an end of vector processing report by the first operating system.