Storage device and method for data sharing

• US 6,275,910 B1
• Filed: 12/20/1999
• Issued: 08/14/2001
• Est. Priority Date: 01/19/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Akira, Yoshida, Minoru, Nakano, Toshio, Kanda, Motohiro
• Primary Examiner(s): Nguyen, Hiep T.
• Application Number:
  US09/467,211
• Time in Patent Office: 603 Days
• Field of Search: 711/147, 711/153, 711/173, 711/112, 710/34, 709/214
• US Class Current: 711/147
• 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: 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 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0674 Disk device
• CPC Class Codes: G06F 3/0676 Magnetic disk device
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

In a computer system including a disk subsystem having channel interface compatible to a count-key-data format and a SCSI interface compatible to a fixed length data format, the disk subsystem is connected to a CPU controlled by an open system operating system through the SCSI interface, and connected to an other CPU controlled by a main frame operating system through the channel interface. The CPU is provided with a CKD record access library and a VSAM access library which accesses in a FBA format the VSAM record stored by the other CPU in a CKD format in the disk subsystem and allows the access by an application program of the CPU as a VSAM record based on VSAM control information.

Claims

1. A computer program stored on a computer readable storage medium being executed on a computer system having a first computer, a second computer, and a storage subsystem coupled to said first computer through a channel interface and to said second computer through a Small Computer System Interface (SCSI), and storing count-key-data format data, said computer program comprising:

a first program code portion, executed on said first computer, for preparing dataset managing information which includes a dataset location address corresponding to a dataset name of the count-key-data format data, wherein said dataset location address is in a count-key-data format; and

a second program code portion, executed on said second computer, responsive to an access request from an application program identifying a dataset name, for generating a block address from a dataset location address based on the dataset managing information, wherein the dataset location address corresponds to the dataset name identified by the disk access request, and for accessing said storage subsystem through the SCSI using the block address.

2. A computer program according to claim 1, wherein said first program code portion obtains dataset location addresses by using a function provided by an operating system running on said first computer.

3. A computer program according to claim 1, wherein said second program code portion comprises sub-program code portion which reads a data block using the block address and retrieves a data portion of said count-key-data format data to provide said application program with the data of said data portion.

4. A method in a computer system having a first computer, a second computer, and a storage subsystem coupled to said first computer through a channel interface and to said second computer through a Small Computer System Interface (SCSI), and storing count-key-data format data, said method comprising:

preparing, on said first computer, dataset managing information which includes a dataset location address corresponding to a dataset name of the count-key-data format data, wherein said dataset location address is in a count-key-data format;

generating, on said second computer, in response to an access request from an application program identifying a dataset name, a block address from a dataset location address based on the dataset managing information, wherein the dataset location address corresponds to the dataset name identified by the disk access request; and

accessing said storage subsystem through the SCSI using the block address.

5. A method according to claim 4, wherein said preparing comprises:

obtaining dataset location addresses by using a function provided by an operating system running on said first computer.

6. A method according to claim 4, wherein said generating comprises:

reading a data block using the block address; and

retrieving a data portion of said count-key-data format data to provide said application program with the data of said data portion.