Access control method for data stored in fixed-block length format in computer configurations utilizing variable length data format interfaces

• US 6,697,866 B1
• Filed: 05/15/2000
• Issued: 02/24/2004
• Est. Priority Date: 02/17/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kano, Yoshiki, Takeuchi, Hisaharu, Arakawa, Hiroshi, Yamagami, Kenji, Watanabe, Haruaki, Homma, Shigeo
• Primary Examiner(s): EL HADY, NABIL M
• Application Number:
  US09/571,061
• Time in Patent Office: 1,380 Days
• Field of Search: 709/227-229, 711/112, 711/113, 711/114
• US Class Current: 709/229
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays

Abstract

According to the invention, techniques for increasing data transfer performance during read or write of the data stored in Fixed-Block Length format in computer configurations in which a plurality of host computers are connected by a CKD format interface to a disk subsystem. Embodiments include systems, apparatuses and methods. Specific embodiments can provide increased data transfer performance in multiple format disk drive subsystems.

Claims

1. An access method for use with a storage apparatus of a computer system, said computer system comprising a computer having an interface in accordance with a variable length data format, and a storage apparatus which stores data recorded on a recording media in accordance with fixed block length format;

wherein said storage apparatus is connected with said computer by the interface in accordance with variable length data format, said method comprising;

generating parameters at said computer, said parameters for transferring the data recorded on said recording media, and an access command which includes information indicating that the access is to data in fixed block length format, said access command being in accordance with variable length data format;

transferring said access command from said computer to said storage apparatus through the interface in accordance with said variable length data format;

analyzing at said storage apparatus the received access command; and

accessing data recorded in accordance with said fixed block length format based on said parameters if said received access command contains the information indicating that said access command is for the data recorded in accordance with said fixed block length format.

2. An access method for use with a storage apparatus according to claim 1, characterized in that:

said information, indicating that said access command is to the data in accordance with said fixed block length format, is realized as a command which is different from a command to access the data in accordance with variable length data format.

3. An access method for use with a storage apparatus according to claim 1, characterized in that:

said information indicating that said access command is to the data in accordance with said fixed block length format is included in said access command as a part of said parameters.

4. An access method for use with a storage apparatus according to claim 1, characterized in that:

the data transfer between said computer and said storage apparatus, accompanied by the access to the data recorded in accordance with said fixed block length format, is performed block by block.

5. A storage apparatus comprising:

a first interface in accordance with variable length data format;

a second interface in accordance with fixed block length format;

a storage unit that stores data used by a computer connected by either of said first or second interface;

a command analyzing means which is used to analyze a command transferred by first computer through said first interface, and comprises the means to distinguish if a command transferred by said first computer is to the data stored in said storage unit in accordance with fixed block length format or not; and

transfer means of data between said first computer and said storage apparatus through a protocol in accordance with said first interface, which data is the data recorded in accordance with fixed block length format to be read out from said storage unit or to be written to said storage unit when the command is transferred from said first computer is defined by said analyzing means as a command to the data recorded in accordance with fixed block length format.

6. A storage apparatus according to claim 5, comprising:

said analyzing means to distinguish said condition based on a predetermined parameter included in a command transferred from said first computer.

7. A storage apparatus according to claim 5, comprising:

said analyzing means to distinguish said condition by discriminating that a command transferred from said first computer is a predetermined command corresponding to data in accordance with fixed block length format.

8. A storage apparatus according to claim 5, comprising:

said transfer means to transfer data between said first computer and said storage apparatus every block by block in accordance with said fixed block length format.

9. A computer system comprising a first computer having a first interface in accordance with variable length data format, and a storage apparatus operable with the first interface in accordance with variable length data format, said storage apparatus prepared with a second interface in accordance with fixed block length format, in which the storage apparatus is connected to the first computer by the first interface;

wherein;

said first computer comprises a generating means for parameters for transferring data recorded on a recording media of said storage apparatus in accordance with fixed block length format, and generating means of a command in accordance with variable length data format, containing the information indicating that the access is to data in accordance with fixed block length format;

said storage apparatus comprising command analyzing means for analyzing a command transferred by the first computer through said first interface, the command analyzing means further comprises a means to distinguish if a command transferred by said first computer is to the data stored in accordance with fixed block length format or not; and

said storage apparatus comprising transfer means of data between said first computer and said storage apparatus through a protocol in accordance with said first interface, which data is the data recorded in accordance with fixed block length format or the data to be stored in fixed block length format when the command transferred from said first computer is defined by said analyzing means as a command to the data recorded in accordance with fixed block length format.

10. A computer system according to claim 9, comprising:

a second computer which is prepared with an interface in accordance with fixed block length format and connects said storage apparatus through said second interface, and wherein

data, which data is recorded in said storage apparatus in accordance with said fixed block length format, is shared between said first computer and said second computer.

11. An access method for use with a storage apparatus of a computer system, said computer system comprising a computer having a variable length data format interface, and a storage apparatus which stores data on a recording media in a fixed block length format;

wherein said storage apparatus is connected with said computer by the variable length data form interface, said method comprising;

generating at said computer, parameters for transferring data recorded on said recording media, and an access command which includes information indicating that data in fixed block length format is to be accessed, said access command being in accordance with variable length data format;

transferring said access command from said computer to said storage apparatus through the variable length data format interface;

analyzing at said storage apparatus, the access command received from said computer; and

accessing data recorded in fixed block length format based on said parameters if said access command received from said computer contains the information indicating that said access command is for the data recorded in fixed block length format.

12. An access method for use with a storage apparatus according to claim 11, wherein:

said information indicating that said access command is directed to fixed block length format data, is realized as a command which is different from a command to access the data in accordance with variable length data format.

13. An access method for use with a storage apparatus according to claim 11, wherein:

said information indicating whether said access command is for data recorded in fixed block length format is included in said access command as a part of said parameters.

14. An access method for use with a storage apparatus according to claim 11, wherein:

transferring said access command from said computer to said storage apparatus through the variable length data format interface, is performed block by block.

15. A storage apparatus comprising:

a first interface in accordance with variable length data format;

a second interface in accordance with fixed block length format;

a storage unit that stores data used by a computer connected by either of said first or second interface;

a command analyzer for analyzing a command transferred by a first computer through said first interface, whereupon, said command analyzer distinguishes if a command transferred by said first computer is directed to data stored in said storage unit in accordance with fixed block length format or not; and

a data transfer module for transferring data between said first computer and said storage apparatus using a protocol in accordance with said first interface;

wherein the data is read out from said storage unit or is written into said storage unit in fixed block length format, provided that when the command is transferred from said first computer, it is determined by said command analyzer to be a command to access data recorded in fixed block length format.

16. An apparatus according to claim 15, wherein said command analyzer determines said command to be a command to access data in fixed block length format based on a predetermined parameter included in said command transferred from said first computer.

17. An apparatus according to claim 15, wherein said command analyzer determines that said command transferred from said first computer is a predetermined command corresponding to data in fixed block length format.

18. An apparatus according to claim 15, wherein said transfer module transfers fixed block length format data between said first computer and said storage apparatus block by block.

19. A computer system comprising:

a first computer having a first interface for exchanging data in a variable length data format,

a second interface for exchanging data in a fixed block length format, and

a storage apparatus connected to the first computer by the first interface, said storage apparatus capable of exchanging data with said first computer via said first interface according to a variable length data format;

wherein;

said first computer further comprises a parameter generator that generates parameters for transferring data recorded on a recording media of said storage apparatus according to a fixed block length format, and a command generator for generating a command according to a variable length data format, wherein the command contains information indicating that data is to be accessed in fixed block length format;

said storage apparatus comprising a command analyzer for analyzing a command transferred by the first computer through said first interface, the command analyzer being operative to distinguish if a command transferred by said first computer is to the data stored in accordance with fixed block length format or not; and

said storage apparatus further comprises a transfer module for transferring data between said first computer and said storage apparatus according to a protocol of said first interface, which data is recorded or stored in a fixed block length format when the command transferred from the first computer is determined by the command analyzer to be a command in which the data is recorded or stored in fixed block length format.

20. A computer system according to claim 19, further comprising

a second computer having a fixed block length format interface that connects said storage apparatus through said second interface, and wherein said first computer and said second computer share data, which data is recorded in said storage apparatus in said fixed block length format.