Abstract: The present invention provides an input and output device for computer system storage that can prevent a computer system being fatally damaged by a computer virus, and also provides a software execution method that by using the input and output device, enables trial software, trial data and mail data to be safely tried. For this, a virtual computer system is used that runs on a computer system. Writes to a hard disk in the virtual computer system are made via a disk cache, and whether or not data is transferred from the disk cache to the hard disk is controlled. Application program snapshot data created by the computer system is recorded on a recording medium that is substantially read-only or transmitted to a different computer system. The snapshot data from the recording medium is read or received by the different computer system and a processing by the application program is resumed in the state in which data transfer from the disk cache to the first storage has stopped.

Abstract: This invention provides a method of suspending and resuming software execution that enables a software execution state to be saved and, as required, transferred to another computer and execution resumed. This is done by including a step of running a second computer program in a real or virtual computer system that emulates functions of a real or virtual computer configured using a first computer program that can save a snapshot of a computer system operation state at a specified time; a step of saving a snapshot of the virtual computer system, or a transmission step; a step of loading the saved or transmitted snapshot on a computer system that substantially corresponds to the real or virtual computer system; and a step of starting operations on a computer system that substantially corresponds to the real or virtual computer system.

Abstract: The present invention provides an input and output device for computer system storage that can prevent a computer system being fatally damaged by a computer virus, and also provides a software execution method that by using the input and output device, enables trial software, trial data and mail data to be safely tried. For this, a virtual computer system is used that runs on a computer system. Writes to a hard disk in the virtual computer system are made via a disk cache, and whether or not data is transferred from the disk cache to the hard disk is controlled. Application program snapshot data created by the computer system is recorded on a recording medium that is substantially read-only or transmitted to a different computer system. The snapshot data from the recording medium is read or received by the different computer system and a processing by the application program is resumed in the state in which data transfer from the disk cache to the first storage has stopped.