JP2000311063A - In-cluster file sharing system including main frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily make a file which a main frame stores accessible by other application programs by equipping an accessible means to an application program which operates on a computer operating system. SOLUTION: An application program 70 uses a function interface Createfile (R) provided by a Windows NT (R) operating system 15, specifies a file name or the like and issues a system call. In a main frame file system 60, a disk 30 is read, a file management structure of the main frame called VTOC is analyzed to examine if a target life, a SYS 1, a RASLOG are registered and, if they are, the file name is delivered to a lock helper 80. The lock helper 80 communicates a file open demand to a lock manager 90 of a computer 20. In the main frame file system 60, opening of the file is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a computer system, and more particularly, to a method of accessing a file on a shared disk by a computer connected to a mainframe in a cluster.

[0002]

2. Description of the Related Art Application for Japanese Patent Application No. 9-52774 (reference)
Describes a disk drive having an interface of FBA, that is, a fixed block format, and an interface of CKD, that is, a count key data format.
A method of sharing with the NIX operating system is disclosed. Further, the patent discloses a method in which an application program running on a UNIX operating system acquires a record stored in a file by the application program running on a mainframe. UNIX is a registered trademark of X / Open in the United States and other countries.

[0003] VAXcluster principles, Roy G. Davis, D
igital Press 1993 discusses file sharing on VAXcluster by Compaq. VAX, VAXcluster, V
MS is a trademark or registered trademark of Compaq Corporation in the United States and other countries.

[0004] In a VAXcluster, a VAX computer and a disk are connected to each other by a kind of local area network. VAX computers can share this disk. All VAX machines have a VMS operating system. The disk is formatted in the format of the VMS operating system file system. The VMS has a lock manager for sharing resources such as files in a cluster.
Therefore, even if a plurality of computers try to access a shared file at the same time, no inconsistency occurs.

[0005] In search of Clusters 2nd Ed., Gregory
F. Pfister, Prentice Hall 1998 describes techniques for general computer clusters.

[0006] Windows NT File System Internals, Raje
ev Nagar, O'reilly 1997 describes the file system structure of the Windows NT operating system. Windows NT is Microsoft corp.
oration is a registered trademark in the United States and other countries.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to easily access a file stored in a mainframe by an application program on a computer other than the mainframe in a computer cluster including the mainframe.

The system of Japanese Patent Application No. 9-52774 has the following problems.

In this system, the UNIX operating system does not support the mainframe file format. For this reason, VTOC (Volume Tables Of Cont
The analysis of the file management structure unique to the mainframe such as ent) is performed using the CKD record access library or VCD.
This is performed by the SAM access library. The application program uses the function provided by calling the function interface provided by the VSAM access library.

On the other hand, the application program
In order to use the file access function originally provided by the UNIX operating system, a function interface defined by the UNIX operating system is called,
This is done by issuing a system call.

Since these two interfaces are different, existing application programs cannot access mainframe files.

On the other hand, in VAXcluster, a cluster can be formed and files can be shared only by a VAX computer on which a VMS operates. Mainframes and personal computers cannot be included in a cluster.

[0013]

SUMMARY OF THE INVENTION The present invention provides an operating system other than a mainframe with a file system capable of analyzing a mainframe file management structure, such as VTOC.

Further, the present invention provides a lock management function for exclusive control of resources such as files among a plurality of computers.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments of the present invention shown in the drawings.

FIG. 1 is a block diagram of a main part of a computer system according to an embodiment of the present invention.

The computer 10 and the computer 20 share the disk 30. A Windows NT operating system 15 operates on the computer 10. In the computer 20, M
The VS / ESA operating system 16 operates. MVS / ESA is available from International
l Bussiness Machines Corp.
Is a registered trademark in the United States and other countries. The shared disk 30 is connected to the computer 10 by the SCSI interface 11 and is connected to the computer 20 by the channel interface 12.

The computers 10 and 20 are connected to each other by a local area network 13.

The computer 10 has an application program 70 and a lock helper 80. The computer 20 has a lock manager 90.

FIG. 1 shows that the Windows NT operating system 15 includes an I / O manager 40, a FAT file system 50, and a mainframe file system 60.

The disk 30 has a file management structure of the MVS / ESA operating system 16, VT.
With an application program having an OC and running on the MVS / ESA operating system 16,
It is assumed that the file has been written.

The application program 70 operating on the computer 10 is not specially created for accessing a mainframe file, but may be an existing ordinary program, for example, commercial spreadsheet software.

The mainframe file system 60
The divided data set stored on the disk 30 by the MVS / ESA operating system 16 is shown to the application program 70 as a directory. Show members of a partitioned dataset as files under that directory. Other datasets are shown as files under the root directory.

FIG. 2 is a flowchart of the processing performed by the Windows NT operating system 15 when the computer 10 opens a file stored in the disk 30 and managed by the file management structure of the mainframe. .

The application program 70 is a Wi
Using CreateFile, a function interface provided by the Windows NT operating system 15,
Issue a system call, specifying the file name, "D: \ SYS1.RASLOG" and the required arguments. Step 100
Then, the I / O manager 40 receiving this request selects the file system mounted on the drive D: because the request is for the drive D :, and transmits the request.

In this case, the FAT file system 50 is in the drive C:
Is mounted on the drive D :. Therefore, the file open request reaches the mainframe file system 60. In step 105, the mainframe file system 60 reads the disk 30, analyzes the mainframe file management structure called VTOC, and checks whether the target file, SYS1.RASLOG, is registered. If there is no file in step 110, an error occurs and the process ends. If so, proceed to step 120. At step 120, mainframe file system 60 passes the file name to lock helper 80.

The lock helper 80 is a Winsock
The local area network 13 is provided by
A file open request is transmitted to the lock manager 90 of the computer 20 via the server. The lock manager 90 returns an error when there is another one that has opened the specified file. Otherwise, return success. When the mainframe file system 60 receives the response from the lock manager 90 via the lock helper 80 in step 130, if it is successful, it proceeds to step 140, records the opening of the file, and ends the processing. Otherwise, the process ends.

The I / O manager 40 informs the application program 70 of an error or success, and if successful, returns a file handle.

FIG. 3 is a flowchart of a process performed by the mainframe file system 60 when the application program 70 uses the file handle of “D: \ SYS1.RASLOG” obtained in FIG. is there.

In the mainframe, the file is C
It is managed by physical addresses called CHHR, that is, cylinder numbers, track numbers, and record numbers.

On the other hand, with the function interface provided by the Windows NT operating system, a file can be accessed from any byte position. See, for example, the function SetFilePointer. For this, Win
It is required that the file system component constituting the dows NT can access a file from an arbitrary byte position.

In the case of a mainframe file, conversion from this byte position to CCHHR is generally not easy. For example, from the top of the file, SYS1.RASLOG, 1
In general, it is not known how many tracks ahead the 00K byte is unless all the tracks that are actually relevant are read. It is RECFM = FS or FBS
This is because it is not specified how many records can be put on each track except for the record called the standard format. See, for example, the IBM manual, MVS / DFP 3.3 Using Data Sets.

For this reason, the mainframe file system 60 disclosed in the present embodiment uses the last accessed byte offset and its C
One set of CHHR correspondences is stored. For sequential access, the next CCHHR is immediately required.

In FIG. 3, an application program 70 attempts to read a file using the function ReadFile. This request reaches the mainframe file system 60 via the I / O manager 40. In step 200, the mainframe file system 60 determines whether the byte position specified by the application program 70 is the continuation of the previous byte position. in that case,
Proceed to step 250. Otherwise, step 210
To see if the specified file consists of records in standard format. In the case of the standard format, since each track includes a fixed number of records determined by the track capacity, in step 220, CCHHR is calculated from the byte position, and the process proceeds to step 250.

If the format is not the standard format, the process proceeds to step 230, and the file is skipped until it is determined in step 240 that the target byte position is reached. In the process of reading the file, correspondence between byte positions and CCHHR is required.

At step 250, the CC determined so far
HH, that is, a track having a cylinder number and a track number is read.

At step 260, the target record is positioned on the track, and the contents of the file are copied to the buffer of the application program 70 in accordance with the specification of the application program 70, and the processing is terminated.

Although the embodiment of the present invention has been described above, it will be apparent to those skilled in the art that the following changes can be made without departing from the scope of the present invention.

The Windows NT operating system 15 can be replaced by any operating system capable of accessing a disk with FBA, a fixed block length interface, for example, a UNIX operating system.

The MVS / ESA operating system 16 can be replaced by any operating system that can access the disk with a CKD or count key data type interface.

The lock helper 80 or the lock manager 90 can be replaced by a network file sharing function provided by the operating system of each computer. For example, LAN file service / E
The file server function of SA or VOS3 NFS can be used as the lock manager 90. LAN File Service / ESA is available from International, USA
al Bussiness Machines Cor
p. Is the product name. VOS3 NFS is a product name of Hitachi, Ltd., Japan. NFS is Sun Microsystem
s, Inc. is a registered trademark.

The file server function is provided by the shared disk 30
Use the network file sharing function to export the files that exist in, and make them accessible from other computers. When the file is opened in the computer 10, the mainframe file system 60 of the computer 10 notifies the file server function of the computer 20 of the opening of the file using the network file sharing function. The file server function permits opening if no other uses the file.

Thereafter, the file is exclusively protected from access by application programs on any computer including the computer 20. In the original network file sharing function, subsequent reading and writing of files are also performed by communication with the file server function. However, in the present invention, the computer 10 directly accesses the disk 30. Thus, high-speed data transfer can be realized without imposing a load on the computer 20.

If the application program 70 does not write to a file, the lock manager 90 can share the same file with a plurality of application programs.

The lock helper 80 or lock manager 90 can be implemented as part of the operating system kernel.

The mainframe file system 60
For each file, the byte position in the file and the CCHH
A plurality of R correspondences can be managed. Or,
When the file is opened, the contents of all the files are read, and it is possible to know the byte position of the file and the complete correspondence of CCHHR.

The mainframe file system 60
Data can be written to a file on the shared disk 30 while holding an appropriate lock. In addition, files can be created and deleted. Windows N
The file written on the disk 30 by the application program running on the T operating system 15 can be read by the application program running on the MVS / ESA operating system 16.

The mainframe file system 60
The character code of the file stored in the disk 30 is
After conversion from EBCDIC to ASCII, it can be provided to the application program. further,
The mainframe file system 60 allows the end user to provide a character code conversion table or a conversion function, and use the conversion function to convert the EBCDIC and the ASCII code.
Conversions other than II can be performed.

The mainframe file system 60
More information included in VTOC, for example, MVS / ES
A The file security information managed by the operating system 16 in the system catalog is
It can be obtained and utilized via a program running on the / ESA operating system 16. Similarly, the mainframe file system 60 can support access to the VSAM data set having the sub-allocation attribute by acquiring the physical storage location of the VSAM cluster from the system catalog.

The mainframe file system 60
Replace the dot "." In the mainframe file name with
It can be shown to the application program 70 as a directory delimiter. In this case, SYS1.RAS
The mainframe file named LOG is visible to the application program 70 as a file named RASLOG located under the directory named SYS1.

[0051]

According to the present invention, in a computer cluster including a mainframe, an application program on a computer other than the mainframe can easily access a file stored in the mainframe.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of a computer system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure of a file open process according to the embodiment of the present invention;

FIG. 3 is a flowchart showing a procedure of a file read process according to the embodiment of the present invention.

[Explanation of symbols]

10, 20: Computer, 30: Shared disk, 60: Mainframe file system.

Claims (1)

[Claims] 1. A storage device having both an interface according to a count key data format and an interface according to a fixed length block format, one or more computers accessing the storage device by an interface according to a count key data format, and the storage device And a computer accessing at least one of the plurality of computers through an interface according to a fixed-length block format. The file stored in the storage device according to the above is transferred to an application operating on an operating system of a computer that accesses the storage device by an interface according to a fixed-length block format among the plurality of computers. Application program, the application by the program interface, the cluster file sharing system including a main frame, characterized in that it comprises means making it possible to access to provide for the operating system file access.