Software prefetch system and method for concurrently overriding data prefetched into multiple levels of cache

• US 6,959,359 B1
• Filed: 06/09/2000
• Issued: 10/25/2005
• Est. Priority Date: 07/14/1999
• Status: Expired due to Fees

• Current Assignee: Hitachi Information Technology Co. Ltd. (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Computer Peripherals Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Matsumura, Hiroyuki, Iwami, Minoru, Taninaka, Dai, Suzuki, Hiroyoshi
• Primary Examiner(s): BATAILLE, PIERRE MICHE
• Application Number:
  US09/591,104
• Time in Patent Office: 1,964 Days
• Field of Search: 711/112, 711/113, 711/114, 711/154, 711/126, 711/170, 711/71, 709/321, 707/205, 710/5, 710/100, 710/51, 713/1, 713/2
• US Class Current: 711/112
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache

Abstract

A cache memory control technology by which set residing data/reset residing data in a cache memory can be executed by individual users. In this system, by execution of set residing data and reset residing data commands, user data spread on plural tracks in the cache memory, using an utility program improves the hit rate of the cache memory.

Claims

1. An external storage system comprising:

a plurality of disk drives for storing data;

a drive interface control unit operatively couple to the disk drives;

a channel interface control unit through which a connection with a supervisory unit can be established for reading and writing data;

a cache memory connected to the drive interface control unit and to the channel interface control unit, the cache memory for temporarily storing data between the disk interface control unit and the channel interface control unit; and

a shared memory connected to the drive interface control unit and to the channel interface control unit, the shared memory for storing information relating to data that is to be staged to the cache memory,

the information being used by the channel interface control unit to stage data that is stored in a plurality of tracks in one or more of the disk drives to the cache memory by way of the drive interface control unit,

the information further being used by the channel interface control unit to destage data from the cache memory to be stored to the disk drives by way of the drive interface control unit,

wherein staging of the data to the cache memory and destaging of the data from the cache memory are performed according to staging and destaging instructions from the supervisory unit, the instructions formulated by the supervisory unit according to criteria provided by a user.

2. The external storage system as claimed in claim 1, in which the staging in or destaging from the cache memory of the user data is executed in a processing unit of a data-set domain.

3. The external storage system as claimed in claim 1, in which the staging or destaging of the data are performed for a data-set domain.

4. The external storage system as claimed in claim 1, in which the information includes a data-set name which is entered by a user.

5. An information processing system having an external storage system and a host unit which is external to the external storage system and connected to the external storage system, in which the external storage system comprises a plurality of disk drives, a drive interface control unit, a channel interface control unit, a shared memory, and a cache memory, in which the host unit executes writing and reading data to the external storage system, and in which

the host unit has a host utility program to manage data in the cache memory, and user defined information or operating information of the external storage system for execution of the host utility program,

wherein the host utility program can issue a resident command to instruct the channel interface control unit to set residing data in the cache memory, and can issue a reset command to instruct the channel interface control unit to reset residing data in the cache memory,

wherein the channel interface unit in the external storage system receives the resident command and the reset command based on the user defined information or the operating information,

wherein the drive interface control unit is operable to store data on the disk drives,

wherein the cache memory is in data communication with the drive interface control unit and the channel interface control unit,

wherein the shared memory is in data communication with the drive interface control unit and the channel interface control unit, and stores first information relating to data stored in the cache memory,

wherein the channel interface control unit sets and resets residing data in the cache based on the first information.

6. The information processing system as claimed in claim 5, in which the residing data is set or reset in the cache memory in units of data-set domains.

7. The information processing system as claimed in claim 5, in which the user defined information includes a data-set name which is entered from a terminal connected to the host unit.

8. A system comprising a host unit and a disk array system separate from the host unit and in data communication therewith, the disk array system comprising:

a plurality of disk drives for storing data;

a drive interface control unit operably coupled to the disk drives for transfer of data therewith;

a channel interface control unit to receive data transfer commands from a host unit;

a cache memory in data communication with channel interface control unit and with the drive interface control unit; and

a shared memory in data communication with channel interface control unit and with the drive interface control unit, the shared memory having stored therein first information relating to data staged in the cache,

wherein the host unit can issue a resident command and a reset command;

wherein in response to receiving a resident command from the host unit, the channel interface control unit accesses the first information to store data received from disk drives into the cache memory,

wherein in response to receiving a reset command from the host unit, the channel interface control unit accesses the first information to reset data that is stored in the cache memory.

9. The system as claimed in claim 8, in which the data is a data-set domain.

10. The system as claimed in claim 8, in which the first information includes a data-set name that is provided by a user.