Electrical computers and digital processing systems: multicomput – Multicomputer data transferring via shared memory
Reexamination Certificate
2000-07-10
2003-10-14
Wiley, David (Department: 2143)
Electrical computers and digital processing systems: multicomput
Multicomputer data transferring via shared memory
C709S217000, C709S238000, C709S246000, C707S793000, C707S793000
Reexamination Certificate
active
06633904
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The contents of Japanese Patent Application No.261,729/99, filed Sept. 16, 1999 in Japan are incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Present Invention
This invention relates to a data exchanging system, which is capable of quickly exchanging and sharing a file between plural computers running different types of operating systems (in the following, called OS), even if the disk space allocations in the system are unknown to each other.
BACKGROUND OF THE INVENTION
FIGS. 12
(A) and (B) are explanation drawings of examples of data exchange in the prior art.
In the prior art, FTP (File Transfer Protocol Program) is well known as a data exchange system between different OSs.
FIG. 12
(A) shows an example of a file exchange system using FTP
110
A and
110
B, which applications work independently of the OS of each computer
100
A,
100
B respectively.
When sending the file
130
A of the computer
100
A to the computer
100
B, the FTP
110
A sends the file data read from the file
130
A stored on the disk drive
120
A by using an application program interface (in the following, called API), which a user program of the computer
100
A uses to FTP
110
B of another computer
100
B over the network
140
. FTP
110
B of the computer
100
B which has received the data writes it to the file
130
B of the disk drive l
20
B of the computer
100
B by using the API.
This system is effective as a system receiving and sending a file between computers, whatever the kind of OS they have, but it has a drawback of a large overhead caused by data transfer over the network.
On the other hand, as a system sharing a file between plural computers using a distributed file system such as NFS(Network File System) is known.
FIG. 12
(B) shows an example of the distributed file system.
The distributed file system is composed of two kinds of computers which are a server computer
200
S having a file
230
and client computer
200
C accessing to the file
200
.
The client computer
200
C sends a request to the server computer
200
S, and OS
210
S of the server computer
200
S accesses to a file on a disk drive
220
, and returns the result to OS
210
C of the client computer
200
C. For example, when writing into the file
230
, the client computer
200
C sends the data to be written to the server computer
200
S over the network
240
, and the server computer
200
S writes the data into the file
230
.
In the distributed file system like this, the file data is sent over the network
240
, so that it causes a problem of a large overhead. Further, as the file operation is implemented by the OS, so that OS
210
C of the client
21
OC should be modified so as to cooperate with the OS
210
S of the server
200
S for using the user program without modification.
Generally as files are stored in a disk drive when the disk drive is connected directly to plural computers and is accessed directly by the computers which exchange or share the data with each other, the above mentioned problem caused by sending data over the network is solved. But, for sharing the data on a disk drive, it is necessary to know how each OS stores the data on the disk drive and for each computer to load the same type of OS, so that the realization is difficult between OSs made by different vendors.
FIG. 13
shows an example of a prior art system sharing the disk drive by plural computers. Each disk drive
320
, the computer
300
A, and the computer
300
B are connected by a fast network
350
, which transmits a disk protocol, called a storage area network (SAN). OS
310
A and
310
B of computer
300
A and
300
B each can access directly to the disk drive
320
B through the storing area network. Accordingly when the OS
310
A and
310
B are same kinds, the computer
300
A and
300
B can share the file on the disk drive
320
, so as to implement directly input and output for the file.
But when the type of the OS
310
A and the OS
310
B are different type (for example, the physical organization of the file
330
A, which the OS
310
A makes and manages, and the file
330
B, which the OS
310
B makes and manages are different), the direct access from the OS
310
A of the computer
300
A to the file
330
B, or the direct access from the OS
310
B of the computer
300
B to the file
330
A are impossible.
Of course, if the file system of the OS
310
A is modified so as to access to the file
310
B, access to the file managed by OS
310
B is realized, but the modification cost is great. Further when necessity to access another file which is made of another kind, the modification for each kind of the file system is necessary, so that actual realization is impossible.
SUMMARY OF THE INVENTION
An object of the present invention is to resolve the above mentioned problem. Another object of the present invention is to quickly exchange or share a file between plural computers of different types of OSs, even if data layout on the external storing device for the file is unknown.
The present invention comprises, for sharing, transmitting or exchanging files managed by operating system between plural computers having different types of operating systems, means for extracting file locations on an external storing device independently of the file systems which are programs in the operating system managing the files, and means for sharing, transmitting and exchanging with another computer by implementing accessing to the external storing device based on the file location information by a device driver which implements an input and output to an external storing device.
A fast data exchange of the present inventions (sharing, transmitting and exchanging) between different kinds of computer is realized by means for extracting the location of the user file data stored by OS on an external storing device such as a disk drive without changing an existing file system of OS except a minimum change of the OS, device drive.
The device drive which implements inputting to and outputting from the storing device includes means executing the file access by changing the extent information, which represents a location of the file directed by a file system on the external storing device to another extent information directed in advance.
The above-mentioned means are implemented by a disk drive for an external storing device, for which the storing system on external storing device managed by another operating system is different, by changing an extent information sent from a file system to another extent information by using an exchanging table which is prepared in advance.
Further the present invention comprises means for transmitting the extent information directing the location of a file in the external storing device from a first computer to a second computer, when transferring the file from the first computer to the second computer of which the OSs are different from each other, means for copying data in the file and realizing the file transmitting by accessing directly to the external storing device based on the extent information received by the second computer.
By this, a fast file transmitting is realized without transmitting the real data only by exchanging the extent information between computers, of which storing systems for the external storing device of file are unknown.
Further the present invention provides means for requesting an extent information of a file, which another computer manages, means for gaining the extent information, and means for sharing the file by accessing directly to the external storing device, in which the file exists by using the extent information obtained from another computer.
By this, sharing directly the file data between computers of which file storing systems are unknown each other can be implemented.
Further the present invention provides means for requesting the extent information of a file, which an OS of another computer manages and obtaining the extent information, means for making a file, which an OS of this computer manages, and obtaining the extent inf
Fujitsu Limited
Nguyen Phuoc
Staas & Halsey , LLP
Wiley David
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