Electrical computers and digital data processing systems: input/ – Input/output data processing – Peripheral configuration
Reexamination Certificate
2001-03-28
2004-01-20
Huynh, Kim (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Peripheral configuration
C710S005000, C709S241000
Reexamination Certificate
active
06681267
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a virtual computer system and a method for swapping input/output devices (hereinafter referred to as “I/O devices”) between virtual machines and a computer readable storage medium, and more particularly to a virtual computer system and method for swapping I/O devices between virtual machines, which system and method provide a command function which enables I/O devices to be swapped between virtual machines through a single operation and enables simultaneous update of I/O definitions of the virtual machines stored in a VM-configuration information file, and computer readable storage medium thereof.
2. Description of the Related Art
FIGS. 10A and 10B
show an example system operation using a virtual computer system. The virtual computer system operates a single real machine as if a plurality of computers were present. Such virtual computers operating on a single real machine are called “virtual machines (VMs).”
In an example case, a virtual machine for daily business and a virtual machine for system development are operated simultaneously on a single real machine. In another example case, future introduction of two real machines is planned for on-line processing and batch processing, respectively, but on a temporary basis, a virtual machine for on-line processing and a virtual machine for batch processing are realized by a single real machine.
FIGS. 10A and 10B
show an example in which a virtual computer system is operated according to the latter scheme. In the system, a virtual machine VM
1
for on-line processing and a virtual machine VM
2
for batch processing are operated on a single real machine R. The virtual machine VM
1
uses duplicated volumes A
1
and A
2
(hereinafter called “dual volumes”). During on-line processing, the virtual machine VM
1
writes identical data (e.g., document data and log data) in the volumes A
1
and A
2
. When such data is subjected to batch processing such as batch print (document output, etc.), the following operation is performed. One (e.g., A
2
) of the dual volumes of the virtual machine VM
1
is detached from the virtual machine VM
1
and is attached to the virtual machine VM
2
; and a volume B of the virtual machine VM
2
is detached from the virtual machine VM
2
and is attached to the virtual machine VM
1
in order to continue the dual-volume operation. After attachment of the volume B, the virtual machine VM
1
copies data of the volume A
1
to the volume B and resumes the dual-volume operation.
FIG. 11
shows a conventional technique for operating a virtual computer system as described above.
A monitor program
100
is a control program for controlling virtual machines VM
1
and VM
2
in a virtual computer system. VM consoles
31
and
32
for operating the virtual machines VM
1
and VM
2
are connected to the virtual machines VM
1
and VM
2
, respectively. When an I/O device
21
(device number: &agr;) attached to the virtual machine VM
1
is swapped with an I/O device
22
(device number: &bgr;) attached to the virtual machine VM
2
at each of the VM consoles
31
and
32
an operator must input successive commands for detaching and attaching the designated I/O device to be swapped.
Further, simultaneously with the swap of the I/O devices, the operator must update definition information of the I/O devices, which information is held in the virtual computer system and used to allocate the I/O devices to the virtual machines when started.
Specifically, the operator must perform operations (1) to (6) shown in FIG.
11
.
(1) Inputting from the VM console
31
a command for detaching the I/O device
21
(device number: &agr;) from the virtual machine VM
1
.
(2) Inputting from the VM console
32
a command for detaching the I/O device
22
(device number: &bgr;) from the virtual machine VM
2
.
(3) Inputting from the VM console
31
a command for attaching the I/O device
22
(device number: &bgr;)to the virtual machine VM
1
(4) Inputting from the VM console
32
a command for attaching the I/O device
21
(device number: &agr;) to the virtual machine VM
2
.
(5) Updating the I/O definition information in the VM-configuration file in order to allocate the I/O device
22
(device number: &bgr;) to the virtual machine VM
1
.
(6) Updating the I/O definition information in the VM-configuration file in order to allocate the I/O device
21
(device number: &agr;) to the virtual machine VM
2
.
With diversified employment of a virtual computer system, virtual machines have come to be used according to various operation schemes. Under such circumstances, use of an operation scheme in which I/O devices are swapped between a plurality of virtual machines has begun. However, due to the common thought that a virtual device configuration is present individually for each virtual machine, there has been present only a concept of attaching a certain I/O device to a virtual machine and detaching the certain I/O device from the virtual machine, but not a concept of swapping I/O devices between a plurality of virtual machines. Therefore, as commands for the monitor program
100
, only a command for attachment of an I/O device and a command for detachment of an I/O device have been provided.
Therefore, conventionally, the operation for swapping I/O devices between virtual machines is very troublesome and requires a long time, as has been described with reference to the example of FIG.
11
.
Moreover, since definition information regarding I/O devices swapped between the virtual machines is merely stored on memory of the virtual computer system, if, after swap of the I/O devices, the virtual computer system goes down due to a failure, the information indicting the fact that the I/O devices have been swapped is lost. Therefore, when the virtual machines are re-started after such a system down, the I/O devices are allocated to the virtual machines in accordance with the contents of a VM-configuration information file, which has been provided in advance on a nonvolatile storage device such as a magnetic disk. Therefore, the allocation of the I/O devices returns to the state before swap. In such a case, before starting the virtual machines, the operator must change the I/O definition information stored in the VM-configuration information file in such a manner that the swap of the I/O devices is reflected in the I/O definition information.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the problems involved in swap of I/O devices between virtual machines such that a large number of commands must be input, that operation is complex and cumbersome, and that the risk of an operator's erroneous operation is high.
Another object of the present invention is to solve the problems involved in update of VM-configuration information such that, since the update of VM-configuration information must be performed separately, overall operation becomes complex and cumbersome, and that in some cases proper operation of virtual machines after the update cannot be guaranteed, because the update may involve errors.
Still another object of the present invention is to provide a virtual computer system which enables I/O devices to be swapped between virtual machines through a single operation.
Still another object of the present invention is to provide a method for swapping I/O devices between virtual machines in a virtual computer system, which method enables I/O devices to be swapped between the virtual machines through a single operation.
Still another object of the present invention is to provide a computer readable storage medium storing a program for swapping I/O devices between virtual machines in a virtual computer system, which program enables I/O devices to be swapped between the virtual machines through a single operation.
The present invention provides a virtual computer system comprises a real machine including first and second input/output devices; a plurality of virtual machines being operated on the real machine and including first and second virtual machin
Kawajiri Yasushi
Ohmura Yukiyoshi
Fujitsu Limited
Greer Burns & Crain Ltd.
Huynh Kim
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