Multi-media storage system

• US 5,758,057 A
• Filed: 06/11/1996
• Issued: 05/26/1998
• Est. Priority Date: 06/21/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Mizuno, Masahiro, Baba, Hiroshi, Yamamoto, Hitoshi, Ito, Kazuhiko, Ogura, Shiro
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Baderman, Scott T.
• Application Number:
  US08/661,942
• Time in Patent Office: 714 Days
• Field of Search: 395/182.05, 395/182.04, 395/182.18, 395/185.08, 395/441, 371/61
• US Class Current: 714/6.32
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097
• CPC Class Codes: G06F 11/0757 by exceeding a time limit, i.e. time-out, e.g. watchdogs
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1088 Reconstruction on already foreseen single or plurality of spare disks
• CPC Class Codes: G06F 11/2056 by mirroring

Abstract

In case of consecutive transmission of a large amount of data such as dynamic image data, a multi-media storage system of the invention generates and transmits data stored in a faulty disk drive when one of a plurality of disk drives being faulty caused by an internal calibration or an error of the disk drive and the faulty disk drive does not respond within a predetermined length of time set in a timeout table. The multi-media storage system cancels an access to the faulty disk drive, generates data to be read from the faulty disk drive based on data stored in the other disk drives of the plurality of disk drives and the redundant data and continues to transmit data.

Claims

1. A multi-media storage system comprising:

(a) a storage device storing data and redundant data; and

(b) a control unit for accessing the data and redundant data stored in the storage device to provide data in response to a request;

wherein the control unit includes;

a timeout table storing a first time limit for providing data after a request;

a data generator generating data from the redundant data stored in the storage device to provide the data in response to the request, when an access to said storage device is not completed when the first time limit has passed, so that the data is provided in response to the request within a second time limit after the first time limit a data buffer area for temporarily storing data and redundant data from the storage device for accesses to the storage device; and

wherein the timeout table stores a plurality of first time limits corresponding to a plurality of users based on a size of available data buffer area so that the data buffer is not emptied before at least a portion of the data accessed from the storage device is stored in the data buffer.

2. The multi-media storage system of claim 1, wherein the storage device is configured as a RAID (Redundant Arrays of Inexpensive Disks) system, and wherein the control unit includes a RAID controller.

3. The multi-media storage system of claim 1, wherein the timeout table stores a plurality of said first time limits corresponding to a plurality of users, and the data generator generates the data when an access is not completed when one of said first time limits, corresponding to a selected one of the users, has passed.

4. The multi-media storage system of claim 3, wherein one of the first time limits is based on a data transmitting speed required by a corresponding user.

5. The multi-media storage system of claim 3, wherein one of the first time limits is based on a response time required by a corresponding user.

6. The multi-media storage system of claim 3, wherein one of the first time limits is based on a response time and a data transmitting speed required by a corresponding user.

7. The multi-media storage system of claim 1, wherein:

the storage device comprises a first storage device storing the data and a second storage device storing the redundant data; and

the control unit accesses the second storage device to retrieve redundant data simultaneously with accessing the first storage device to retrieve data in response to the request.

8. The multi-media storage system as in claim 1, wherein the timeout table stores a third time limit, and wherein the control unit further includes:

means for reaccessing the storage device when an access to the storage device is completed after the first time limit and before the third time limit;

means for disconnecting the storage device when an access to the storage device is not completed before the third time limit;

means for disconnecting the storage device after a predetermined number of reaccesses have occurred.

9. A multi-media storage system comprising:

(a) a plurality of data disk drives for respectively storing of multi-media data;

(b) a redundant disk drive for storing redundant data of the multi-media data stored in the plurality of disk drives; and

(c) a control unit, including;

a plurality of ports connected to the plurality of disk drives and the redundant disk drive, for accessing the plurality of disk drives and the redundant disk drive to provide data in response to a request and

at least one unused port connectable to a disk drive;

the multi-media storage system further comprising;

a new disk drive storing multi-media data to be attached to the at least one unused port; and

a compute means for computing new redundant data based on the redundant data stored in the redundant disk drive and the multi-media data stored in the new disk drive and storing the new redundant data in the redundant disk drive, when the new disk drive is connected to the at least one unused port.

10. The multi-media storage system of claim 9, further comprising an access suspension means for suspending access to a group of multi-media data of a faulty disk drive in case that one of the plurality of disk drives becomes faulty.

11. A data accessing method for a multi-media storage system having a plurality of disk drives, coupled to users through a host system and having a storage device, a control unit and a data buffer, the data storing method comprising the steps of:

storing data and redundant data in the storage device;

setting a first time limit in a timeout table in the control unit for each user;

receiving a data access request from the host system for data;

setting a first timer upon receiving the data access request based upon the time limit set in the timeout table;

issuing a data access instruction to one of the disk drives;

generating redundant data to transmit to the host system when the one disk drive does not respond within the first time limit as determined by the first timer so that the data is provided in response to the request within a second time limit after the first time limit temporarily storing data and redundant data from the storage device for accesses to the storage device in the data buffer, and wherein the timeout table stores a plurality of first time limits corresponding to a plurality of users based on a size of available data buffer area so that the data buffer is not emptied before at least a portion of the data accessed from the storage device is stored in the data buffer.

12. The data storing method of claim 11, further comprising the steps of:

setting a second timer with a third time limit;

disconnecting the one disk drive and indicating to the control unit a fault of the one disk drive, when the one disk drive does not respond within the third time limit determined by the second timer;

determining if data stored in the one disk drive can be recovered by a retry function when the disk drive responds after the first time limit and within the third time limit;

recovering the data stored in the one disk drive by the retry function when the data is able to be recovered;

writing the redundant data generated at the generating step into the one disk drive when the data of the one disk drive is unable to be recovered by the retry function.

13. The data storing method of claim 12, comprising the steps of:

outputting an error to an error log of the control unit when the data of the one disk drive is unable to be recovered by the retry function;

determining if a number of errors in the error log for the one disk drive exceeds a predetermined number of errors;

disconnecting the one disk drive and indicating to the control unit a fault of the one disk drive when the number of errors exceeds the predetermined number of errors.

14. A data storing method for a multi-media storage system including a plurality of disk drives for respectively storing one group of multi-media data, a disk drive for storing redundant data, and a control unit connected to the plurality of the disk drives, and connected to the disk drive for storing redundant data, the data storing method comprising the step of:

adding a new disk drive storing a new group of multi-media data to the multi-media storage system by connecting the new disk drive to the control unit;

computing new redundant data based on the redundant data stored in the disk drive for storing redundant data and the new group of multi-media data stored in the new disk drive; and

storing the new redundant data in the disk drive for redundant data.

15. The data storing method of claim 14, further comprising the step of suspending access to a group of multi-media data of one of the plurality of the disk drives when the one disk drives becomes faulty.