Severe environment data recording system

• US 5,493,676 A
• Filed: 02/06/1995
• Issued: 02/20/1996
• Est. Priority Date: 06/29/1993
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Amundson, Dennis L.
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Elmore, Stephen C.
• Application Number:
  US08/385,601
• Time in Patent Office: 379 Days
• Field of Search: 340/955, 395/575, 395/425, 371/5.5, 371/8.1, 364/245.3, 364/269.2, 364/268.5, 364/281.9, 364/424.04, 364/246.1, 364/268.9, 364/285.3, 364/944.61, 364/964, 364/970, 365/211
• US Class Current: 714/42
• CPC Class Codes: G06F 11/3034 where the computing system component is a storage system, e.g. DASD based or network based digital input from or digital output to record carriers G06F3/06; digital recording or reproducing 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 11/3058 Monitoring arrangements for monitoring environmental properties or parameters of the computing system or of the computing system component, e.g. monitoring of power, currents, temperature, humidity, position, vibrations thermal management in cooling arrangements of a computing system G06F1/206
• CPC Class Codes: G11C 29/765 in solid state disks
• CPC Class Codes: G11C 29/88 with partially good memories

Abstract

An apparatus which includes one or more optical disk memory systems, one or more magnetic disk memory systems, and one semiconductor memory system, to store large amounts of data while operating under potentially severe environmental conditions. The preferred storage media for the apparatus is the optical disk memory system, but when environmental conditions do not permit successful operation of the optical disk memory, the apparatus switches storage of data to an alternate storage media such as magnetic disk memory or semiconductor memory until the severe environmental conditions subside. When environmental conditions subside, the optical disk memory is updated with the data stored on magnetic disk memory and semiconductor memory. Monitoring of environmental conditions is performed by the storage media systems, not by environmental sensors external to the system.

Claims

1. A fault tolerant data storage system having a hierarchy of multiple classes of storage devices for recording data without any data loss due to faults resulting from operating in severe environmental conditions, comprising:

an input device to receive the data to be recorded in real-time,

at least one main storage device of a primary class of the storage hierarchy and having a first set of operational characteristics including a first level of fault tolerances for storing received data, said main storage device including fault detection apparatus providing a fault signal when a predetermined environmental condition exceeds one of said first level of fault tolerances, thereby preventing storing said received data in said at least one main storage device,

at least one first alternate storage device of a secondary class of the storage hierarchy and having a second set of operational characteristics including a second level of fault tolerances, said second level of fault tolerances being substantially higher than said first level of fault tolerances,

a storage controller coupled to said input device to receive requests to store said received data, coupled to said at least one main storage device to direct the recording of said received data on said at least one main storage device and to receive said fault signal, and coupled to said at least one first alternate storage device to redirect the recording of said received data on said at least one first alternate storage device only when said fault signal is provided by said at least one main storage device, such that none of said received data is lost,

at least one first alternate storage device of a secondary class of the storage hierarchy and having a second set of operational characteristics including a second level of fault tolerances, said second level of fault tolerances being substantially higher than said first level of fault tolerances,

2. The fault tolerant data storage system of claim 1 wherein said at least one main storage device is an optical disk storage device.

3. The fault tolerant data storage system of claim 1 wherein said at least one first alternate storage device is a magnetic disk storage device.

4. The fault tolerant data storage system of claim 1 wherein said fault signal is provided when said received data cannot be stored due to any combination of excessive shock, vibration, or temperature extremes which exceed said first level of fault tolerances.

5. The fault tolerant data storage system of claim 1 wherein said at least one first alternate storage device further includes alternate fault detection apparatus providing an alternate fault signal when said predetermined environmental condition exceeds one of said second level of fault tolerances, thereby preventing storing said receiving data in said at least one first alternate storage device.

6. The fault tolerant data storage system of claim 5 wherein said alternate fault signal is provided when said received data cannot be stored due to any combination of excessive shock, vibration, or temperature extremes which exceed said second level of fault tolerances.

7. The fault tolerant data storage system of claim 5 and further including:

at least one second alternate storage device of a tertiary class of the storage hierarchy and having a third set of operational characteristics including a third level of fault tolerances, said third level of fault tolerances being substantially higher than said second level of fault tolerances, coupled to said storage controller, whereby said storage controller redirects the recording of said received data on said at least one second alternate storage device only when said alternate fault signal is provided by said at least one first alternate storage device, such that none of said received data is lost.

8. The fault tolerant data storage system of claim 7 wherein said at least one second alternate storage device is a semiconductor memory storage device.

9. A fault tolerant data storage system having a hierarchy of multiple classes of storage devices for recording data without any data loss due to faults resulting from operating in severe environmental conditions, comprising:

input means for receiving data to be recorded in real-time,

main storage means of a primary class of the storage hierarchy and having a first set of operational characteristics including a first level of fault tolerances for storing said data,

fault detection means coupled to said main storage means for providing an environmentally induced fault signal when a predetermined environmental condition exceeds one of said first level of fault tolerances, thereby preventing storing said received data in said main storage means,

first alternate storage means of a secondary class of the storage hierarchy and having a second set of operational characteristics including a second level of fault tolerances, said second level of fault tolerances being substantially higher than said first level of fault tolerances, and

storage controller means coupled to said input means for receiving requests to store received data, coupled to said main storage means for directing the recording of said data on said main storage means, coupled to said fault detection means for receiving said environmentally induced fault signal, and coupled to said first alternate storage means for redirecting the recording of said data on said first alternate storage means only when said environmentally induced fault signal is provided by said fault detection means, such that none of said received data is lost.

10. The fault tolerant data storage system of claim 9 and further including:

alternate fault detection means coupled to said first alternate storage means and said storage controller means for providing an alternate fault signal to said storage controller means when said predetermined environmental condition exceeds one of said second level of fault tolerances, thereby preventing storing said received data in said first alternate storage means.

11. The fault tolerant data storage system of claim 10 and further including:

second alternate storage means of a tertiary class of the storage hierarchy and having a third set of operational characteristics including a third level of fault tolerances, said third level of fault tolerances being substantially higher than said second level of fault tolerances, coupled to said storage controller means for storing said received data, whereby said storage controller means redirects the recording of said received data on said second alternate storage means only when said alternate fault signal is provided by said alternate fault detection means, such that none of said received data is lost.

12. A fault tolerant data recording system having a hierarchy of multiple classes of storage devices, the hierarchy including at least primary and secondary classes, the primary class having storage devices with a first set of operational characteristics including a first level of fault tolerances, the secondary class having storage devices with a second set of operational characteristics including a second level of fault tolerances which is substantially higher than the first level of fault tolerances, the fault tolerant data recording system operating to store data in a storage device of the secondary class only after an attempt to store the data in a storage device of the primary class has failed, for storing data received in a data recording request from an input/output adapter coupled to a general purpose computer, without any data loss due to faults resulting from operating in severe environmental conditions, comprising:

at least one input/output adapter connected to the input/output adapter of the general purpose computer to receive the data recording request,

a storage controller connected to said input/output adapter including circuitry to receive the data recording request form said input/output adapter,

a storage devices interface connected to said storage controller including circuitry to receive a storage request from said storage controller to store the data contained in the data recording request,

at least one optical disk memory of the primary class of the storage hierarchy and having a first level of fault tolerances connected to said storage devices interface to store the data and to return a first fault signal when storage of the data fails due to a predetermined environmental condition exceeding one of said first level of fault tolerances, thereby preventing storage of the data by said at least one optical disk memory,

at least one alternate memory of the secondary class of the storage hierarchy and having a second level of fault tolerances substantially higher than said first level of fault tolerances connected to said storage devices interface to store the data only when said at least one optical disk memory has returned said first fault signal and to return a second fault signal when storage of the data on said alternate memory fails due to said predetermined environmental condition exceeding one of said second level of fault tolerances, thereby preventing storage of the data by said at least one alternate memory.

13. The fault tolerant data recording system as recited in claim 12 wherein said at least one alternate memory is a magnetic disk memory.

14. The fault tolerant data recording system as recited in claim 12 wherein said at least one alternate memory is a semiconductor memory.

15. The fault tolerance data recording system as recited in claim 13 and having a tertiary class of the storage hierarchy, the tertiary class having at least one storage device with a third set of operational characteristics including a third level of fault tolerances whch is substantially higher than said second level of fault tolerances, the fault tolerant data recording system operating to store the data in a storage device of the tertiary class only after an attempt to store the data in said at least one alternate memory has failed, further including:

a semiconductor memory of the tertiary class of the storage hierarchy and having a third level of fault tolerances, said third level of fault tolerances being substantially higher than said second level of fault tolerances, connected to said storage devices interface to store the data only when said at least one alternate memory has returned said second fault signal to said storage devices interface.

16. The fault tolerant data recording system as recited in claim 12 wherein said storage controller includes:

means coupled to said storage devices interface for sending said storage request to said storage devices interface for transfer of the data to said at least one optical disk memory,

means coupled to said storage devices interface for redirecting said storage request to said storage devices interface for transfer of the data to said at least one alternate memory when said first fault signal is received, and

means for receiving said first fault signal via said storage devices interface from said at least one optical disk memory and said at least one alternate memory.

17. The fault tolerant data recording system of claim 16 further including means for periodically updating said at least one optical disk memory with the data stored on said at least one alternate memory such that said at least one optical disk memory stores a complete step of the data.

18. The fault tolerant data recording system as recited in claim 15 wherein said storage controller includes:

mean coupled to said storage devices interface for sending said storage request to said storage devices interface for transfer of the data to said at least one optical disk memory,

means coupled to said storage devices interface for redirecting said storage request to said storage devices interface for transfer of the data to said at least one alternate memory only when said first fault signal is received,

means coupled to said storage devices interface for redirecting said storage request to said storage devices interface for transfer of the data to said semiconductor memory only when said second fault signal is received, and

means for receiving said first fault signal via said storage devices interface from said at least one optical disk memory, and fore receiving said second fault signal via said storage devices interface from said at least one alternate memory.

19. The fault tolerant data recording system of claim 18 further including means for periodically updating said at least one optical disk memory with the data stored on said at least one alternate memory and the data stored on said semiconductor memory such that said at least one optical disk memory stores a complete set of the data.

20. In a fault tolerant data storage system having a hierarchy of multiple classes of storage devices, the hierarchy including at least primary and secondary classes, the primary class having storage devices with a first set of operational characteristics including a first level of fault tolerances, the secondary class having storage devices with a second set of operational characteristics including a second level of fault tolerances which is substantially higher than the first level of fault tolerances, and comprising an input/output adapter for receiving a data recording request containing data to be stored, a storage controller connected to said input/output adapter for controlling storage of the data, a storage devices interface connected to said storage controller for transferring the data, at least one optical disk memory of the first class of the storage hierarchy and having a first level of fault tolerances, and at least one magnetic disk memory of the second class of the storage hierarchy and having a second level of fault tolerances, each optical disk memory and magnetic disk memory connected to said storage devices interface for storing the data, a method of recording data without any data loss while operating under severe environmental conditions comprising the steps of:

(a) receiving the data recording request to store the data,

(b) storing the data on an optical disk memory,

(c) receiving a first fault signal from said optical disk memory if the data cannot be reliably stored on said optical disk memory due to a predetermined environmental condition exceeding one of the first level of fault tolerances,

(d) storing the data on a magnetic disk memory only if said first fault signal is received from said optical disk memory, and

(e) updating periodically the data stored on said optical disk memory with the data stored on said magnetic disk memory, and removing the data stored on said magnetic disk memory.

21. In a fault tolerant data recording system having a hierarchy of multiple classes of storage devices the hierarchy including at least primary, secondary, and tertiary classes, the primary class having storage devices with a first set of operational characteristics including a first level of fault tolerances, the second class having storage devices with a second set of operational characteristics including a second level of fault tolerances which is substantially higher than the first level of fault tolerances, the tertiary class having storage devices with a third set of operational characteristics including a third level of fault tolerances which is substantially higher than the second level of fault tolerances, and comprising an input/output adapter for receiving a data recording request containing data to be stored, a storage controller connected to said input/output adapter for controlling storage of the data, a storage devices interface connected to said storage controller for transferring the data, at least one optical disk memory of the first class of the storage hierarchy and having a first level of fault tolerances, at least one magnetic disk memory of the second class of the storage hierarchy and having a second level of fault tolerances, and at least one semiconductor memory of the third class of the storage hierarchy and having a third level of fault tolerances, each storage device connected to the storage devices interface for storing the data, a method of recording data without any data loss while operating under severe environmental conditions comprising the steps the steps of:

(a) receiving the data recording request to store the data,

(b) storing the data on an optical disk memory,

(c) receiving a first fault signal form said optical disk memory if the data cannot be stored on said optical disk memory due to a predetermined environmental condition exceeding one of the first level of fault tolerances,

(d) storing the data on a magnetic disk memory only if said first fault signal is received from said optical disk memory,

(e) receiving a second fault signal from said magnetic disk memory if the data cannot be stored on said magnetic disk memory due to said predetermined environmental condition exceeding one of the second level of fault tolerances,

(f) storing the data on a semiconductor memory only if said second fault signal is received from said magnetic disk memory, and

(g) updating periodically the data stored on said optical disk memory with the data stored on said magnetic disk memory and the data stored on said semiconductor memory, and removing the data stored on said magnetic disk memory and said semiconductor memory.

22. A fault tolerant data recording system having a hierarchy of at least three classes of storage devices for storing data received in data recording requests from at least one input/output adapter connected to at least one general purpose computer, comprising:

at least one input/output adapter connected to the at least one input/output adapter of the at least one general purpose computer to receive the data recording requests;

a storage devices interface to receive a storage request to store the data contained in the data recording requests;

at least one optical disk memory of a primary class of the storage devices hierarchy, said at least one optical disk memory having a first set of operational characteristics including a first level of fault tolerances, said at least one optical disk memory connected to said storage devices interface to store the data and to return a first fault signal when storage of the data on said at least one optical disk memory fails due to a predetermined environmental condition exceeding one of said first level of fault tolerances;

at least one magnetic disk memory of a secondary class of the storage hierarchy, said at least one magnetic disk memory having a second set of operational characteristics including a second level of fault tolerances substantially higher than said first level of fault tolerances, said at least one magnetic disk memory connected to said storage devices interface to store the data only when said at least one optical disk memory has returned said first fault signal, and to return a second fault signal when storage of the data on said at least one magnetic disk memory fails due to said predetermined environmental condition exceeding one of said second level of fault tolerances;

at least one semiconductor memory of a tertiary class of the storage hierarchy, said at least one semiconductor memory having a third set of operational characteristics including a third level of fault tolerances substantially higher than said second level of fault tolerances, said at least one semiconductor memory connected to said storage devices interface to store the data only when said at least one magnetic disk memory has returned said second fault signal; and

a storage controller connected to said at least one input/output adapter and said storage devices interface, said storage controller including

means for receiving the data recording request from said input/output adapter;

means for sending said storage request to said storage devices interface for transfer of the data to said at least one optical disk memory;

means for redirecting said storage request to said storage devices interface for transfer of the data to said at least one magnetic disk memory only when said at least one optical disk memory returns said first fault signal to said storage controller via said storage devices interface;

means for redirecting said storage request to said storage devices interface for transfer of the data to said at least one semiconductor memory only when said at least one magnetic disk memory returns a second fault signal to said storage controller via said storage devices interface;

file allocation table means for storing table entries identifying where the data is stored on said at least one optical disk memory;

auxiliary file allocation table means for storing table entries identifying where the data is stored on said at least one magnetic disk memory and said at least one semiconductor memory; and

means for periodically updating said at least one optical disk memory with the data stored on said at least one magnetic disk memory and the data stored on said at least one semiconductor memory according to said table entries stored by said file allocation table means and said auxiliary file allocation table means such that said at least one optical disk memory stores a complete set of the data contained in the data recording requests, and the data is removed from said at least one magnetic disk memory and said at least one semiconductor memory.

23. In a fault tolerant data recording system having a hierarchy of at least three classes of storage devices, the hierarchy including at least primary, secondary, and tertiary classes, the primary class having storage devices with a first set of operational characteristics including a first level of fault tolerances, the secondary class having storage devices with a second set of operational characteristics including a second level of fault tolerances which is substantially higher than the first level of fault tolerances, the tertiary class having storage devices with a third set of operational characteristics including a third level of fault tolerances which is substantially higher than the second level of fault tolerances, and having an input/output adapter for receiving a data recording request containing data to be stored, a storage controller connected to the input/output adapter for controlling storage of the data, a storage devices interface connected to the storage controller for transferring the data to one of a plurality of storage devices including at least one optical disk memory of the primary class of the storage hierarchy and having a first level of fault tolerances, at least one magnetic disk memory of the secondary class of the storage hierarchy and having a second level of fault tolerances, and at least one semiconductor memory of the tertiary class of the storage hierarchy and having a third level of fault tolerances, each storage device connected to the storage devices interface for storing the data, a file allocation table having table entries identifying where the data is stored on the at least one optical disk memory, and an auxiliary file allocation table having table entries identifying where the data is stored on the at least one magnetic disk memory and the at least one semiconductor memory, a method of recording data without any data loss while operating under severe environmental conditions comprising the steps of:

(a) receiving the data recording request to store the data from the input/output adapter,

(b) storing the data on the optical disk memory,

(c) receiving a first fault signal form the optical disk memory when the data cannot be stored on the optical disk memory due to a predetermined environmental condition exceeding one of the first level of fault tolerances,

(d) creasing a table entry in the file allocation table to identify where the data is stored on the optical disk memory when said first fault signals not received from the optical disk memory,

(e) storing the data ton the magnetic disk memory only if said first fault signal is received from the optical disk memory,

(f) receiving a second fault signal form the magnetic disk memory when the data cannot be stored on the magnetic disk memory due to said predetermined environmental condition exceeding one of the second level of fault tolerances,

(g) creating a first table entry in the auxiliary file allocation table to identify where the data is stored on the magnetic disk memory when said second fault signal is not received from the magnetic disk memory,

(h) storing the data on the semiconductor memory only if said second fault signal is received from the magnetic disk memory,

(i) creating a second table entry in the auxiliary file allocation table to identify where the data is stored on the semiconductor memory,

(j) updating periodically the data stored on the optical disk memory with the data stored on the magnetic disk memory and the data stored on the semiconductor memory based on said table entries in the file allocation table and said first table entries and said second table entries in the auxiliary file allocation table and removing the data stored on the magnetic disk memory and the semiconductor memory, and

(k) updating the file allocation table and the auxiliary file allocation table to reflect changes in storage locations of the data as a result of periodic updates performed in Step (j).

24. For use in recording data in an environment having varying levels of environmental disturbance, a fault tolerant data storage system comprising:

an input device to receive data to be recorded;

a first storage device for reliably storing data up to a first level of environmental disturbance, and including a first fault circuit to provide a first fault signal when said first storage device is subjected to a level of environmental disturbance greater than said first level of environmental disturbance;

a second storage device for reliably storing data up to a second level of environmental disturbance, wherein said second level is greater than said first level; and

a storage controller coupled to said input device to receive requests to store data, coupled to said first storage device to direct the recording of data on said first storage device and to receive said first fault signal, and coupled to said second storage device to redirect the recording of data on said second storage device only when said first fault signal is provided by said first fault circuit.

25. The fault tolerant data storage system of claim 24, wherein said first storage device has a first data recording rate and said second storage device has a second data recording rate higher than said first data recording rate.

26. The fault tolerant data storage system of claim 25, wherein said second storage device further includes a second fault circuit to provide a second fault signal when said second storage device is subjected to a level of environmental disturbance greater than said second level of environmental disturbance such that said second storage device cannot reliably record data.

27. The fault tolerant data storage system of claim 26, and further including a third storage device for reliably storing data up to a third level of environmental disturbance, wherein said third level is higher than said second level, said storage controller being further coupled to said second fault circuit and said third storage device to redirect the recording of data on said third storage device only when said second fault signal is provided by said second fault circuit.

28. The fault tolerant data storage system of claim 27, wherein said third storage device has a third data recording rate higher than said first data recording rate and higher than said second data recording rate.

29. The fault tolerant data storage system of claim 28, wherein said first storage device is an optical disk drive, said second storage device is a magnetic disk drive, and said third storage device is a semiconductor memory device.