Preservation system for volatile memory with nonvolatile backup memory
First Claim
1. An apparatus for providing memory power, comprising:
- means for receiving external power;
volatile memory means for storing data while at least a first level of power is provided;
nonvolatile memory means for storing data;
backup power storage means for storing said external power and for providing backup power to said volatile memory means at a level higher than said first level during an outage of said external power; and
control means for transferring data from said volatile memory means to said non-volatile memory means in response to the detection of an outage of said external power, and for delaying said transfer until said backup power falls below said first level of power.
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Accused Products
Abstract
In a preservation system for a volatile memory associated with a nonvolatile memory, an energy storage portion accumulates energy while power is provided normally. When a power outage occurs, the stored energy is supplied to the volatile memory. Enough backup power is stored to accommodate the vast majority of unintentional interruptions of power. Eventually, after removal of external power, when the backup power decreases to a predetermined amount, data in the volatile memory is transferred to the nonvolatile memory. The preferred use for the preservation system is in an environment with vibration and/or power switching transients that affect the supply of power, such as an aircraft.
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Citations
22 Claims
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1. An apparatus for providing memory power, comprising:
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means for receiving external power; volatile memory means for storing data while at least a first level of power is provided; nonvolatile memory means for storing data; backup power storage means for storing said external power and for providing backup power to said volatile memory means at a level higher than said first level during an outage of said external power; and control means for transferring data from said volatile memory means to said non-volatile memory means in response to the detection of an outage of said external power, and for delaying said transfer until said backup power falls below said first level of power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9)
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8. An apparatus for providing memory power, comprising:
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means for receiving external power; volatile memory means for storing data while a first level of power is provided; nonvolatile memory means for storing data while power is not provided; backup power storage means for storing said external power and for providing the stored external power as backup power to said volatile memory means during an outage of said external power; and control means for controlling transfer of the data stored in said volatile memory means from said volatile memory means to said nonvolatile memory means when said backup power falls below said first level of power and for providing a count of a number of transfers of data from said volatile memory means to said nonvolatile memory means.
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10. A preservation system for volatile memory means used in an aircraft to store data while a first level of external power is provided, comprising:
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nonvolatile memory means for storing data while power is not provided; backup power storage means for storing said external power and for providing the stored external power as backup power to said volatile memory means during an outage of said external power; and control means for controlling transfer of the data stored in said volatile memory means from said volatile memory means to said nonvolatile memory means when said backup power falls below said first level of power and for providing a count of a number of transfers of data from said volatile memory means to said nonvolatile memory means.
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11. An apparatus for providing memory power, said apparatus comprising, in combination,
a volatile memory in which data can be stored and from which data can be retrieved by a computer except when data is stored in, or is being transferred to or from a non-volatile memory for data preservation, a non-volatile memory for storing data transferred from said volatile memory, means for conducting power from an external power source to said volatile memory, a backup power supply for supplying power to said volatile memory during power outages of said external source, and a data transfer control device for detecting said power outages and supplying backup power to said volatile memory and preventing data transfer from said volatile memory to said non-volatile memory during each of said power outages for a predetermined length of time, said length of time being sufficient to prevent said data transfer for a substantial portion of temporary outages of said external source, and for causing said data transfer to occur after an outage has persisted longer than said predetermined length of time.
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15. An apparatus for providing memory power, said apparatus comprising, in combination,
a volatile memory for storing data, a non-volatile memory for storing data transferred from said volatile memory, said non-volatile memory being capable of executing a limited number of read-write cycles before it wears out, means for conducting power from an external power source to said volatile memory, a backup power supply for supplying power to said volatile memory during power outages of said external source, and a data transfer control device for detecting said power outages and supplying backup power to said volatile memory and preventing data transfer from said volatile memory to said non-volatile memory during each of said power outages for a predetermined length of time, said length of time being sufficient to prevent said data transfer for a substantial number of temporary outages of said external source, and for causing said data transfer to occur after an outage has persisted longer than said predetermined length of time, whereby said number of read-write cycles for a given length of operating time for said memory is substantially limited.
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17. A method of controlling data storage and retrieval in an aircraft computer system having a volatile memory and a power supply, said power supply being subject to relatively frequent temporary power outages, said method comprising the steps of:
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(a) determining the duration of the majority of said temporary power outages; (b) providing backup power from a backup power supply; (c) providing a non-volatile memory for storing data transferred from said volatile memory to prevent data loss; (d) detecting the onset of each of said temporary power outages; (e) supplying back-up power to said volatile memory during each of said outages; and (f) during each outage, transferring data from said volatile memory to said non-volatile memory only after the duration of said outage becomes greater than the duration of a majority of said temporary outages. - View Dependent Claims (18, 19, 20, 21)
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22. A method of limiting the computer down time and data transfer operations in a computer system having a power supply, a volatile memory for use in the operations of said computer system, and a non-volatile memory for storing data from the memory to protect it from destruction due to temporary power outages, said method comprising the steps of:
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(a) detecting the onset of each of said outages and supplying backup power to said volatile memory in response thereto; (b) maintaining said backup power during each outage for a predetermined time longer than the duration of a majority of said power outages; and (c) transferring data from said volatile memory to said non-volatile memory only if said outage lasts longer than said predetermined time.
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Specification