Computer, computer system, and data transfer method

• US 20020004845A1
• Filed: 03/02/2001
• Published: 01/10/2002
• Est. Priority Date: 07/06/2000
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Oeda, Takashi, Yamamoto, Yasutomo, Shoyama, Takahiko
• Granted Patent: US 7,058,692 B2
• Time in Patent Office: Days
• US Class Current: 709/240
• CPC Class Codes: G06F 15/167 using a common memory, e.g. mailbox
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

The present invention provides techniques, including a method and system, for transferring data between computer systems, for example, a mainframe and a Personal Computer (PC), having storage systems of different formats, efficiently. One embodiment provides a method for transferring data from a first system, having a first processor and a first memory, using a first format to a second system, having a second processor and a second memory, using a second format. The method includes a first system receiving data of a first format from a first disk unit; processing the data of the first format into transformed data, where the transformed data is the data transformed into the second format; storing the transformed data in the first memory; and sending the transformed data from the first memory to the second system responsive to a request from the second system.

Claims

1. A first computer system, having a processor and a memory, said memory having a first data of a first format, said first computer system further comprising:

an interface for receiving from a second computer system an access command to access a second data of a second format, said second format different from said first format;

first command processing means for storing said first data in said memory in said second format, according to a write command issued by said processor to write said first data; and

second command processing means for transferring said first data stored in said memory in said second format to said second computer system, according to a read command issued by said second computer system to read said second data.

2. The first computer system of claim 1 wherein said second format is a Fixed Block Architecture (FBA) format.

3. The first computer system of claim 1 wherein said first format is a Count Key Data (CKD) format.

4. The first computer system of claim 1 wherein said first format is an intermediate format.

5. A computer comprising a processor and a memory, said computer further comprising:

an interface to another computer for receiving from said another computer a first access command to access data of a second format different from a first format;

an interface to a first storage unit for using said first storage unit to store data in said second format;

first command processing means for, by use of said first storage unit and said memory, emulating a logical first storage unit storing data of said first format, and processing a second access command issued by said processor to access data of said first format; and

second command processing means for, by use of said first storage unit and said memory, emulating a logical second storage unit storing data of said second format, and processing said first access command issued by said another computer to access data of said second format;

wherein when said second access command issued by said processor is a write command for a predetermined area in said logical first storage unit, said first command processing means writes write data into a first storage area in said storage unit corresponding to said predetermined area, and causes the write data to stay resident in said memory.

6. The computer as claimed in claim 5, further comprising:

an interface to a second storage unit for using said second storage unit to store data in said second format,

wherein said processor reads said data of said first format from said logical first storage unit, transforms said data of said first format into a predetermined format as necessary, and issues a second write command to write re-formatted data in a second predetermined area in said logical second storage unit.

7. The computer as claimed in claim 6, wherein said processor supplies said another computer with information necessary for said another computer to specify a second storage area in said logical second storage unit corresponding to a third storage area in said second storage unit which also corresponds to said predetermined area in said logical first storage unit.

8. A method of transferring information, wherein a first fixed-sized block storage unit, which stores data of a fixed-sized block format, transfers information to a first computer comprising a second fixed-sized block storage unit, said information being stored by a second computer comprising a variable-sized record storage unit which stores data of a variable-sized record format, said method comprising:

in said second computer, emulating both a logical variable-sized record storage unit for a process in said second computer and a logical fixed-sized block storage unit for said first computer by use of a storage area in said second computer;

in said second computer, writing information to be transferred to said first computer into said logical variable-sized record storage unit;

in said first computer, issuing a read request to said logical fixed-sized block storage unit; and

in said second computer, reading the information written in said logical variable-sized record storage unit according to said read request.

9. The method of transferring information as claimed in claim 8, wherein said storage area is an area in a main storage unit of said second computer.

10. A method of accessing data by a first computer, wherein said first computer, comprising a fixed-sized block storage unit storing data of a fixed-sized block format, accesses information stored in a second computer, comprising a variable-sized record storage unit storing data of a variable-sized record format, said method comprising:

for said first computer, emulating a logical fixed-sized block storage unit by use of a storage area of said second computer in which information read from said variable-sized record storage unit is stored; and

accessing information in said logical fixed-sized block storage unit from said first computer.

11. The method of claim 10 wherein said accessing information comprises a read request by said first computer to a storage control processor in said second computer.

12. A method for transferring data from a first system, comprising a first processor and a first memory, using a first format to a second system, comprising a second processor and a second memory, using a second format, said method comprising:

receiving data of a first format from a first disk unit by said first system;

processing said data of said first format into transformed data, wherein said transformed data is said data transformed into said second format;

storing said transformed data in said first memory; and

sending said transformed data from said first memory to said second system responsive to a request from said second computer.

13. The method of claim 12 wherein said processing is by a storage control processor in said first system.

14. A system for data transfer from a user computer using a fixed-sized block format to a mainframe computer using a variable-sized record format, comprising:

a disk unit using said variable-sized record format, wherein said disk unit is coupled with said mainframe computer;

a data access module for receiving data of said fixed-sized block format from said user computer; and

said mainframe computer, comprising a storage processor and a memory, said memory for storing said data, and said storage processor for transforming said data into a variable-sized record format for storage in said disk unit.

15. The system of claim 14 wherein said memory is a disk cache.

16. The system of claim 14 wherein said memory comprises a logical variable-sized record disk emulated by a fixed-sized block disk and a disk cache.

17. A system for data transfer from a user computer using a fixed-sized block format to a mainframe computer using a variable-sized record format, comprising:

a first disk unit for storing first data in said fixed-sized record format; and

a processor of said user computer coupled with said first disk unit, said processor sending a read request to said mainframe for reading said first data stored on a logical fixed-sized block format disk of said mainframe in said fixed-sized block format;

wherein said first data on said logical fixed-sized block format disk corresponds to second data on a logical variable-sized record disk, said logical variable-sized record disk, comprising a disk and a disk cache.

18. A system for transferring data from a first disk format at a first system, to a second disk format at a second system, via a communication line, comprising:

a first disk unit comprising a first data item in said first disk format;

said first system coupled with said first disk unit, said first system comprising;

a disk cache;

a processor for transforming said first data item into a second data item in said second disk format and storing said second data item in said disk cache; and

a data access module for sending said second data item to said second system from said disk cache; and

said second system, comprising a second disk unit using said second disk format for storing said second data item.

19. The system of claim 18 wherein said data access module sends said second data item to said second system responsive to receiving a read request by said processor from said second system.

20. The system of claim 18 wherein said first disk format is a CKD format.

21. The system of claim 18 wherein said second disk format is a FBA format.

22. The system of claim 18 wherein said first system is a mainframe computer.

23. The system of claim 18 wherein said second system is a PC or a workstation computer.

24. A method for a first computer system, comprising a fixed sized block storage unit for storing information of a fixed-size format and a processor, to access a first data of a variable-sized record format, said first data stored in a variable-sized record storage unit of a second computer system, said method comprising:

said first computer system requesting said first data from said second computer system;

receiving notice of completion of transforming said first data to second data from said second computer system, wherein said second data is of said fixed-sized block format and stored in a memory of said second computer system;

generating third data by performing format transformation, comprising data extraction, on said second data;

transferring said third data from said memory to said first computer system; and

storing said third data in said fixed sized block storage unit.

25. A computer readable medium storing code for transferring data from a first system, comprising a first processor and a first memory, using a first format to a second system, comprising a second processor and a second memory, using a second format, said computer readable medium comprising:

code for receiving data of a first format from a first disk unit by said first system;

code for processing said data of said first format into transformed data, wherein said transformed data is said data transformed into said second format;

code for storing said transformed data in said first memory; and

code for sending said transformed data from said first memory to said second system responsive to a request from said second computer.

26. A computer readable medium storing code for accessing data by a first computer, wherein said first computer, comprising a fixed-sized block storage unit storing data of a fixed-sized block format, accesses information stored in a second computer, comprising a variable-sized record storage unit storing data of a variable-sized record format, said computer readable medium comprising:

code for emulating a logical fixed-sized block storage unit by use of a storage area of said second computer in which information read from said variable-sized record storage unit is stored; and

code for accessing information in said logical fixed-sized block storage unit from said first computer.