WO2002017077A1

WO2002017077A1 - Method and apparatus for transferring data between a non-volatile memory module and a storage device

Info

Publication number: WO2002017077A1
Application number: PCT/US2000/034257
Authority: WO
Inventors: Amnon Strasser
Original assignee: Exanet Co.
Priority date: 2000-08-24
Filing date: 2000-12-21
Publication date: 2002-02-28
Also published as: AU2001230751A1

Abstract

A method and apparatus for transferring data between a non-volatile memory module (5) and a storage device (7) is provided. The method includes the steps of detecting a loss of system power, writing data from non-volatile memory to the storage device, and turning off the power supply of the non-volatile memory module. The apparatus used to transfer the data includes a memory device, an uninterruptible power supply (6) used to supply back-up power to the non-volatile memory, a storage device connected to the memory device, and a controller (8) to control the transferring of data and powering down and powering up of the power supply.

Description

METHOD AND APPARATUS FOR TRANSFERRING DATA BETWEEN A NON-VOLATILE MEMORY MODULE AND A

STORAGE DEVICE

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is an application filed under 35 U.S.C. § 111(a), claiming benefit pursuant to 35 U.S.C. § 120 of the filing date of the

Provisional Application Serial No. 60/227,379 filed on August 24, 2000, pursuant to 35 U.S.C. § 111(b). The Provisional Application Serial No. 60/227,379 is incorporated herein by reference for all it discloses.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for transferring data in a non-volatile write cache architecture, and more particularly, to a method and apparatus for transferring data between a nonvolatile memory module and a storage device.

2. Description of the Related Art

In a client/server environment, it is often required that write transactions cached by a server are kept in non-volatile memory until transferred to stable storage. Non-volatile memory modules usually require batteries or any other uninterruptible power supply for proper operation. In conventional systems, either the non-volatile memory module battery supplies power all the time, regardless of changes in system power, or the non-volatile

memory module battery supplies power during an entire power failure time

period.

Referring to FIG. 1, a conventional non- volatile memory module, including a central processing unit 1, a non- volatile memory 2, a main storage

device 3 and an uninterruptible power supply 4 is illustrated. In the

conventional module, a processing unit, a non-volatile memory and a main

storage device are connected to each other. A battery or other uninterruptible power supply backs up the non-volatile memory. Because the battery backing up the non-volatile memory is not under any control, except possibly being

controlled to supply power during an entire power failure time period, it

remains on until the battery itself loses power or until power is restored.

Therefore, the non-volatile memory always remains powered up. However, the longer the battery is required to stay on before system power is restored, the more the life of the battery will be shortened. K the battery is

required to maintain power for too long before system power is restored, the

battery can lose power, thereby causing a loss of data stored in the non- volatile

memory.

SUMMARY OF THE INVENTION

The invention has been made in view of the above circumstances and to overcome the above problems and limitations of the prior art.

In order to solve the above problems, it is an object of the present invention to provide a method and apparatus for transferring data between a

non-volatile memory module and a stable storage device that does not require a battery for data retention.

It is another object of the present invention to provide a computer

program product for the above data transfer method.

According to an aspect of the invention, a non-volatile memory

module can be implemented such that it consists of a battery backed up memory and a stable storage device that does not require a battery for data

retention. Upon power loss, battery power can be used to transfer the battery

backed up memory onto the stable storage device. When the transfer

operation is completed, battery power is no longer required to maintain the data stored in the cache; hence, the power can optionally be disconnected to prolong battery life.

For example, it is possible to implement such a non-volatile write

cache mechanism by directing, routing, or trapping all the write requests to a non-volatile memory module (i.e., a volatile memory module backed up by battery) and then writing the data to system disks when appropriate. Thus, the

synchronous write will occur at non-volatile memory speed, not at disk speed.

As the non-volatile write cache fills up, the non-volatile write cache transfers

the data to system disks in portions that are large enough to allow the disk drivers to optimize the order of the writes. Reads that hit or match blocks in the non-volatile write cache can also realize performance benefits since the data does not have to be read from system disks. The non- volatile write cache is used to ensure that the data is not lost because of power failure or a system

crash. The non-volatile write cache can be an integral part of a computer

system or a different entity connected logically by any means to the required

computer system that needs such a beneficial functionality. Upon power fail, the non-volatile write cache will transfer its memory

content into stable storage such as a hard disk or disks, after a controller

determines that the external voltage level is less than or approaching a

predetermined level. After power resumes and the controller determines that

the external voltage level exceeds or is approaching a predetermined level, the non-volatile write cache will be restored from the designated disk and the operation can be continued. This mechanism maintains the data integrity

required by such systems in a transparent manner. By using a disk or disks as

a stable storage, the battery size in terms of dimension and power capacity can be reduced and the total capacity of the non-volatile write cache can be

increased by orders of magnitude.

According to another aspect of the invention, it is also possible to

incrementally shut down memory devices after each one is backed up onto the

stable storage device.

According to another aspect of the invention, each memory device is powered by its own uninterruptible power supply, which can be shut down

independently.

According to another aspect of the invention, a computer system comprises a plurality of non-volatile memory modules, called a redundant array of inexpensive non-volatile memories, and a plurality of storage nodes,

each of which is connected to the plurality of non-volatile memory modules. Each of the storage nodes comprises a storage device and a controller. This aspect of the invention provides enhanced reliability and fault tolerance,

because of the redundancy of the non-volatile memories.

According to another aspect of the invention, a computer system

comprises a plurality of non-volatile memory sub-systems that are connected

together. Each of the plurality of non- volatile memory sub-systems comprises

at least one memory device, an uninterruptible power supply connected to at

least one memory device, a storage device connected to at least one memory

device, and a controller.

Additional aspects and advantages of the invention will be set forth in part in the description that follows and in part will be obvious from the

description, or may be learned by practice of the invention. The aspects and

advantages of the invention may be realized and attained by means of the

instrumentaUties and combinations particularly pointed out in the appended

claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute

a part of this specification illustrate aspects of the invention and, together with the written description, serve to explain the aspects, advantages and principles of the invention. In the drawings, FIG. 1 illustrates a block diagram of a conventional non-volatile memory module;

FIG. 2 illustrates a block diagram of a non-volatile memory module

with an embedded micro-controller;

FIG. 3 illustrates a block diagram of a non-volatile memory module

with an embedded processing unit;

FIG. 4 illustrates a block diagram of a non-volatile memory module

with a disk controller;

FIG. 5 illustrates a block diagram of a non-volatile memory module with a system processing unit;

FIG. 6 illustrates a block diagram of a non-volatile memory module with an external processing unit backed up by the uninterruptible power

supply of the non- volatile memory module;

FIG. 7 illustrates a block diagram of a non-volatile memory module

with an external processing unit backed up by an external uninterruptible power supply;

FIG. 8 illustrates a block diagram of a non-volatile memory module

with an embedded micro-controller, including a plurality of memory devices,

all of which share the same uninterruptible power supply and stable storage; FIG. 9 illustrates a block diagram of a non-volatile memory module, including a plurality of memory devices, each of which shares the same stable storage, but has its own uninterruptible power supply;

FIG. 10 illustrates a block diagram of a memory system including a plurality of non-volatile memory modules, each with its own embedded micro¬

controller, uninterruptible power supply, stable storage, and main storage;

FIG. 11 illustrates a block diagram of a memory system including a

non- volatile memory system connected to three storage nodes;

FIG. 12 illustrates a flow chart of a method of transferring data from

non-volatile memory to stable storage in accordance with an aspect of the

invention;

FIGS. 13A and 13B illustrate a flow chart of a method of transferring

data from non-volatile memory to stable storage, sequentially, in accordance

with an aspect of the invention; and

FIG. 14 illustrates a flow chart of a method of transferring data from

stable storage to non-volatile memory, main memory, or processing unit memory in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Prior to describing the aspects of the invention, some details

concerning the prior art will be provided to facilitate the reader's understanding of the invention and to set forth the meaning of various terms.

As used herein, the term "computer system" encompasses the widest

possible meaning and includes, but is not limited to, standalone processors, networked processors, mainframe processors, and processors in a client/server relationship. The term "computer system" is to be understood to include at least a memory and a processor. In general, the memory will store, at one time or another, at least portions of executable program code, and the processor will execute one or more of the instructions included in that executable program code.

It will be appreciated that the term "predetermined operations," the term "computer system software," and the term "executable code" mean substantially the same thing for the purposes of this description. It is not necessary to the practice of this invention that the memory and the processor be physically located in the same place. That is to say, it is foreseen that the processor and the memory might be in different physical pieces of equipment or even in geographically distinct locations.

As used herein, one of skill in the art will appreciate that "media" or "computer-readable media" may include a diskette, a tape, a compact disc, an integrated circuit, a cartridge, a remote transmission via a communications circuit, or any other similar medium useable by computers. For example, to distribute computer system software, the supplier might provide a diskette or might transmit the instructions for performing predetermined operations in some form via satellite transmission, via a direct telephone link, or via the Internet.

Although computer system software might be "written on" a diskette, "stored in" an integrated circuit, or "carried over" a communications circuit, it

will be appreciated that, for the purposes of this discussion, the computer

usable medium will be referred to as "bearing" the instructions for performing

predetermined operations. Thus, the term "bearing" is intended to encompass the above and all equivalent ways in which instructions for performing predetermined operations are associated with a computer usable medium.

Therefore, for the sake of simplicity, the term "program product" is hereafter used to refer to a computer useable medium, as defined above, which bears instructions for performing predetermined operations in any form.

A detailed description of the aspects of the invention will now be given referring to the accompanying drawings.

Referring to FIG. 2, a block diagram of a non- volatile memory module, according to an aspect of the invention, is illustrated. A non- volatile memory 5, a stable storage 7 and a main storage 3 are all connected together. An uninterruptible power supply 6 is connected to and supplies power to the nonvolatile memory 5 and the stable storage 7. A microcontroller 8, which controls the data transfer between the non-volatile memory 5 and the stable storage 7, is embedded in the non- volatile memory 5. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the nonvolatile memory 5 onto the stable storage 7. When the transfer operation is completed, uninterruptible power supply power is no longer required to maintain the data stored in the non-volatile memory; hence, the power can optionally be disconnected to prolong uninterruptible power supply life. Referring to FIG. 3, another aspect of the invention is illustrated, which is similar to FIG. 2, except that in FIG. 3 a processing unit 10 is embedded in the non-volatile memory 9 and controls the data transfer, instead of a microcontroller 8. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the non-volatile memory 9 onto the

stable storage 7. When the transfer operation is completed, uninterruptible

power supply power is no longer required to maintain the data stored in the non-volatile memory; hence, the power can optionally be disconnected to

prolong uninterruptible power supply life.

Referring to FIG. 4, another aspect of the invention is illustrated. FIG.

4 is similar to FIGS. 2 and 3, except that the non- volatile memory 12 does not include an embedded processing unit 10 or an embedded microcontroller 8, and FIG. 4 includes a disk controller 11 connected to the stable storage 7 and

backed up by the uninterruptible power supply 6. The disk controller 11

controls the data transfer. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the non-volatile memory 12 onto the stable storage 7. When the transfer operation is completed, uninterruptible

power supply power is no longer required to maintain the data stored in the

non-volatile memory; hence, the power can optionally be disconnected to

prolong uninterruptible power supply life.

FIG. 5 illustrates another aspect of the invention, which includes a system processing unit 14, which is connected to the non- volatile memory 12,

the main storage 3, and the stable storage 7 and is supplied power from the

uninterruptible power supply 6. The system processing unit 14 controls the data transfer. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the non- volatile memory 12 onto the stable storage 7. When the transfer operation is completed, uninterruptible power supply power is no longer required to maintain the data stored in the non-volatile memory;

hence, the power can optionally be disconnected to prolong uninterruptible power supply life.

In FIG. 6 the data transfer is controlled by an external system

processing unit 14, which is backed up by the uninterruptible power supply 6

of the non-volatile memory module. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the non-volatile

memory 12 onto the stable storage 7. When the transfer operation is

completed, uninterruptible power supply power is no longer required to

maintain the data stored in the non-volatile memory; hence, the power can optionally be disconnected to prolong uninterruptible power supply life.

FIG. 7 is similar to FIG. 6, except that the external system processing

unit 14 of FIG. 7 has its own external uninterruptible power supply 6a for power back up. Upon power loss, power from the uninterruptible power

supply 6 can be used to transfer the non-volatile memory 12 onto the stable storage 7. When the transfer operation is completed, uninterruptible power supply power is no longer required to maintain the data stored in the non¬

volatile memory; hence, the power can optionally be disconnected to prolong uninterruptible power supply life.

FIG. 8 illustrates a non-volatile memory module with a plurality of memory devices that all share the same uninterruptible power supply and stable storage. A non-volatile memory 15, a stable storage 7 and a main

storage 3 are all connected together. An uninterruptible power supply 6 is connected to and supplies power to the non-volatile memory 5 and the stable

storage 7 during a system power loss. A microcontroller 8, which controls the

data transfer between the memory devices (MDl-MDn) 13a-13n of the non¬

volatile memory 5 and the stable storage 7, is embedded in the non- volatile memory 5. Upon power loss, power from the uninterruptible power supply 6 can be used to transfer the non- volatile memory 5 onto the stable storage 7.

When the transfer operation is completed, uninterruptible power supply power

is no longer required to maintain the data stored in the non-volatile memory; hence, the power can optionally be disconnected to prolong uninterruptible power supply life. To further prolong uninterruptible power supply life, the

power to each memory device can be shut off sequentially after each memory

device is transferred.

FIG. 9 illustrates another aspect of the invention in which each memory device has its own uninterruptible power supply, which can be shut off independently. A non-volatile memory 16, a stable storage 7 and a main

storage 3 are all connected together. An uninterruptible power supply 6 is

connected to and supplies power to the non- volatile memory 5 and the stable storage 7 during a system power loss. A microcontroller 8, which controls the data transfer between the memory devices (MDl-MDn) 13a-13n of the non- volatile memory 5 and the stable storage 7, is embedded in the non-volatile

memory 5. The data transfer is performed in the same way as described

above, except each uninterruptible power supply l4a-14n can be shut off individually and sequentially after each memory device is transferred, rather than shutting off a single uninterruptible power supply for all of the memory

devices.

FIG. 10 shows another aspect of the invention including a plurality of

non-volatile memory modules, called a redundant array of inexpensive non-

volatile memories, each of which is connected together. Each of the plurality

of non-volatile memory modules has its own uninterruptible power supply,

stable storage and main storage that comprises a memory system. Each of the non-volatile memory modules 25a-25n, the microcontrollers 28a-28n, the stable storage devices 27a-27n, and the main storage devices 23a-23n operate

as explained above to transfer data and shut off each uninterruptible power

supply 26a-26n. Each non-volatile memory module is connected to the other

non-volatile memory modules through an interconnect 29. Because of the redundancy of the non- volatile memories, this aspect of the invention provides

enhanced reliability and fault tolerance.

The memory system of FIG. 11 comprises a non- volatile memory

system with an uninterruptible power supply 26a, a stable storage 27a, and a non-volatile memory 25a with an embedded microcontroller 28a, and three main storage nodes connected together through an interconnect 29. Each of

the main storage nodes comprises a processing unit 32 and a main storage

device 33. This arrangement allows for transfer of data to a plurality of main

storage devices, rather than to a single main storage device.

FIG. 12 shows a flow chart of a method of transferring data, according to an aspect of the invention. At S100, the method determines whether the system voltage is below a certain predetermined level. If the system voltage is

not below a certain predetermined level, the method returns to S100. If the

system voltage is below the predetermined level, at S102, data is transferred

from non-volatile memory to stable storage. At S103, a determination is made

whether all the data has been transferred to stable storage. If all the data has

been transferred, at S 104 the non- volatile memory power supply is turned off to prolong the non-volatile memory power supply life.

FIGS. 13A and 13B show a flow chart of a method of transferring data,

according to another aspect of the invention. In this method power is turned

off to individual memory devices after each memory device has had its data

transferred to stable storage. Referring to FIG. 13 A, at S200, it is determined if system power is below a predetermined level. In S201, if system power is not below the predetermined level, the method returns to S200. If system

power is below the predetermined level, data is transferred from the first non-

volatile memory module to stable storage at S202. In S203, it is determined if

the data transfer from the first non- volatile memory module is complete. If all the data has not been transferred yet, the method returns to S202. If the data

transfer is complete, the power supplied to the first non-volatile memory module is turned off in S204.

Referring to FIG. 13B, which is a continuation of FIG. 13 A, it is determined in S205 if any non-volatile memory modules are remaining that have not had their data transferred. If not, then the method terminates. If any non-volatile memory modules are remaining, then, in S206, the data is transferred from the next non-volatile memory module to stable storage. If the data transfer is not complete in S207, the method returns to S206. When the

data transfer is complete in S207, the method proceeds to block B, which

returns to S205. With this method, power can be saved by shutting off

individual memory devices as soon as the data has been transferred from them, rather than waiting for the entire non-volatile memory to be transferred from before shutting off power to the memory devices.

FIG. 14 shows a flow chart of a method of transferring data, according

to another aspect of the invention. In S300, system power is restored. In S301, it is determined where data in stable storage is to be transferred. If it is determined that the data is to be transferred back to non-volatile memory in

S302, the data is transferred to non- volatile memory in S303. If the data is not

to be transferred to non- volatile memory, it is determined in S304 if the data is

to transferred to main storage. If it is determined that the data is to be

transferred to main storage, it is transferred to main storage in S305. If the data is not to be transferred to main storage, it is determined in S306 if the

data is to be transferred to processing unit memory. If so, the data is

transferred to processing unit memory in S307. If it is determined that the data is not to be transferred to processing unit memory in S306, the method terminates. Also, after the data is transferred to any of the memories the method terminates.

According to another aspect of the present invention, there is provided

computer program product, in which programs for executing the steps of detecting a loss of system power, writing data from non-volatile memory to

the storage device, and turning off the power supply of the non-volatile

memory module, by computers, are recorded in order to enable a computer

system to transfer data between a non-volatile memory module and a storage device. The computer program product comprises software instructions for

enabling the computer system to perform predetermined operations, and a

computer readable medium bearing the software instructions. The

predetermined operations of the computer program product determine if a

voltage level of the computer system is less than a predetermined level. Based on that determination, if the voltage level is less than a predetermined level,

the predetermined operations flush data from the non- volatile memory to the

storage device. The predetermined level that is used is a voltage level

appropriate for the application. Typically, this voltage level will be non-zero. The computer program product also comprises predetermined operations that

turn off the uninterruptible power supply of the non- volatile memory module.

The computer program product also detects a restoration of system

power to the non-volatile memory module and turning on the power supply.

The predetermined operations of the computer program product determine if

the voltage level of the computer system is above the predetermined level following a shutdown of the uninterruptible power supply. As before, the

predetermined level is the voltage level that is appropriate for the application.

Based on a determination if the voltage level is above the predetermined level, the computer program product includes predetermined operations that turn on the uninterruptible power supply if the voltage level is above the

predetermined level.

The computer program product further includes predetermined

operations that transfer the data that was previously transferred into the

storage device to several different types of memory. A voltage level being

above a predetermined level triggers all these data transfers. The voltage level

being above a predetermined level assumes that the voltage level had

previously dropped below that predetermined level and data was transferred

from the non-volatile memory. First, the predetermined operations can

transfer the data back to the non- volatile memory. Second, the predetermined

operations can transfer the data from the storage device to a main storage

device. Third, the predetermined operations can transfer the data from the

storage device to a processing unit memory.

If the non-volatile memory comprises a plurality of memory devices,

the predetermined operations of the computer program product are further

configured to transfer the data to the storage device. The predetermined

operations sequentially transfer data from each of the memory devices

comprising the non-volatile memory to the storage device. The predetermined

operations sequentially shut off power to each of the memory devices after

each memory device is transferred to the storage device.

According to another aspect of the present invention, there is further

provided a computer system for transferring data between a non-volatile

memory module powered by an uninterruptible power supply and a storage device. The computer system comprises software means for determining if a voltage level of the computer system is less than a predetermined level. As

before, the predetermined voltage level is determined by the application.

Typically, the data transfer would occur before the voltage level had reached

zero volts. The computer system further comprises software means for, if the

voltage level is less than the predetermined level, flushing data from the nonvolatile memory to the storage device. The computer system further comprises software means for turning off the uninterruptible power supply of

the non- volatile memory module. Based on a determination if the voltage

level is above the predetermined level, the computer system further includes

software means that turn on the uninterruptible power supply if the voltage

level is above the predetermined level. Turning on the uninterruptible supply

assumes that the voltage level had dropped below the predetermined level and

data was transferred from the non-volatile storage to a storage device.

The computer system further includes software means that transfer the

data that was previously transferred into the storage device to several different

types of memory. A voltage level that is above a predetermined level triggers all these data transfers. The voltage level being above a predetermined level

assumes that the voltage level had previously dropped below that

predetermined level and data was transferred from the non-volatile memory.

First, the software means can transfer the data back to the non-volatile memory. Second, the software means can transfer the data from the storage

device to a main storage device. Third, the software means can transfer the data from the storage device to a processing unit memory.

If the non- volatile memory comprises a plurality of memory devices, the software means of the computer system are further configured to transfer the data to the storage device in sequential fashion. The software means sequentially transfer data from each of the memory devices comprising the non-volatile memory to the storage device. The software means sequentially shut off power to each of the memory devices after each memory device is transferred to the storage device.

According to another aspect of the present invention, there is further provided an executable program for a computer system for transferring data between a non-volatile memory module and a storage device. The executable program comprises a first executable code portion which, when executed on a computer, determines if a voltage level of the computer system is less than a predetermined level. As described earlier, this voltage level is selected on the basis of the application. Typically, this level is non-zero. The executable program further comprises a second executable code portion which, when executed on a computer, if it determines that the voltage level is less than a predetermined level, transfers data from the non-volatile memory to the storage device. The executable program further comprises a third executable code portion which, when executed on a computer, turns off the

uninterruptible power supply of the non-volatile memory module. The

uninterruptible power supply is shut off after all the data has been transferred

from the non-volatile memory module. Based on a determination if the voltage level is above the predetermined level, the executable program further comprises an executable code portion that turns on the uninterruptible power supply if the voltage level is above the predetermined level. Turning on the

uninterruptible supply assumes that the voltage level had dropped below the

predetermined level and data was transferred from the non- volatile storage to a

storage device.

The executable program further includes an executable portion that

transfers the data that was previously transferred into the storage device to

several different types of memory. A voltage level that is above a

predetermined level triggers all these data transfers. The voltage level being above a predetermined level assumes that the voltage level had previously dropped below that predetermined level and data was transferred from the non-volatile memory. First, the executable code portion can transfer the data

back to the non-volatile memory. Second, the executable code portion can

transfer the data from the storage device to a main storage device. Third, the executable code portion can transfer the data from the storage device to a processing unit memory.

If the non-volatile memory comprises a plurality of memory devices,

the executable program further includes and executable code portion

configured to transfer the data to the storage device in sequential fashion. The executable code portion sequentially transfers data from each of the memory devices comprising the non-volatile memory to the storage device. The executable code portion sequentially shuts off power to each of the memory devices after each memory device is transferred to the storage device.

The foregoing description of the aspects of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The principles of the invention and its practical application were described in order to explain the invention to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

Thus, while only certain aspects of the invention have been specifically described herein, it will be apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention. Further, acronyms are used merely to enhance the readability of the specification and claims. It should be noted that these acronyms are not intended to lessen the generality of the terms used and they should not be construed to restrict the scope of the claims to the embodiments described therein.

Claims

CLAIMS What is claimed is: 1. A non-volatile memory module comprising: at least one memory device; an uninterruptible power supply connected to at least one memory device; and a controller connected to at least one memory device and the uninterruptible power supply.

2. The non- volatile memory module of claim 1, wherein the controller is embedded in the memory device.

3. The non-volatile memory module of claim 1, wherein the controller is a processing unit external to the non-volatile memory module.

4. The non- volatile memory module of claim 1, wherein the controller is a system processing unit external to the non-volatile memory module.

5. The non- volatile memory module of claim 1, wherein the controller is a disk controller.

6. The non- volatile memory module of claim 1, wherein the uninterruptible power supply is a battery.

7. The non- volatile memory module of claim 1, wherein a storage device is connected to at least one memory device, and wherein the controller shuts down the unintermptible power supply after at least one memory device is completely transferred into the storage device.

8. The non- volatile memory module of claim 7, wherein the controller transfers data from at least one memory device into the storage device when the controller determines that an external voltage level is less than a predetermined level.

9. The non- volatile memory module of claim 7, wherein the controller transfers data from at least one memory device into the storage device when the controller determines that an external voltage level is approaching a predetermined level.

10. The non- volatile memory module of claim 7, wherein the controller transfers data previously transferred into the storage device to at least one memory device when the controller determines that an external voltage level exceeds a predetermined level.

11. The non-volatile memory module of claim 7, wherein the controller transfers data previously transferred into the storage device to at least one memory device when the controller determines that an external voltage level is approaching a predetermined level.

12. The non- volatile memory module of claim 1, wherein at least one memory device further comprises a plurality of memory devices.

13. The non- volatile memory module of claim 12, wherein a storage device is connected to the plurality of memory devices, and wherein the controller sequentially transfers data from the plurality of memory devices into the storage device.

14. The non-volatile memory module of claim 13, wherein the controller sequentially shuts off the power to each of the plurality of memory devices after it has been completely transferred into the storage device.

15. The non- volatile memory module of claim 13, wherein the controller transfers data from the plurality of memory devices into the storage device when the controller determines that an external voltage level is less than a predetermined level.

16. The non-volatile memory module of claim 13, wherein the controller transfers data from the plurality of memory devices into the storage device when the controller determines that an external voltage level is approaching a predetermined level.

17. The non-volatile memory module of claim 13, wherein the controller transfers data previously transferred into the storage device to the plurality of memory devices when the controller determines that an external voltage level exceeds a predetermined level.

18. The non- volatile memory module of claim 13, wherein the controller transfers data previously transferred into the storage device to the plurality of memory devices when the controller determines that an external voltage level is approaching a predetermined level.

19. A non- volatile memory module comprising: at least one memory device for storing data; an uninterruptible power supply for supplying power to at least one memory device; and a controller for flushing data from at least one memory device to a storage device.

20. The non-volatile memory module of claim 19, wherein the controller is embedded in at least one memory device.

21. The non- volatile memory module of claim 19, wherein the controller is a processing unit external to the non- volatile memory module.

22. The non-volatile memory module of claim 19, wherein the controller is a system processing unit external to the non-volatile memory module.

23. The non- volatile memory module of claim 19, wherein the controller is a disk controller.

24. The non- volatile memory module of claim 19, wherein the uninterruptible power supply is a battery.

25. The non- volatile memory module of claim 19, wherein a storage device is connected to at least one memory device, and wherein the controller shuts down the uninterruptible power supply after the memory device is completely transferred into the storage device.

26. The non- volatile memory module of claim 25, wherein the controller tiansfers data from at least one memory device into the storage device when the controller determines that an external voltage level is less than a predetermined level.

27. The non-volatile memory module of claim 25, wherein the controller transfers data from at least one memory device into the storage device when the controller determines that an external voltage level is approaching a predetermined level.

28. The non-volatile memory module of claim 25, wherein the controller transfers data previously transferred into the storage device to at least one memory device when the controller determines that an external voltage level exceeds a predetermined level.

29. The non-volatile memory module of claim 25, wherein the controller transfers data previously transferred into the storage device to at least one memory device when the controller determines that an external voltage level is approaching a predetermined level.

30. The non-volatile memory module of claim 19, wherein at least one memory device further comprises a plurality of memory devices.

31. The non- volatile memory module of claim 30, wherein a storage device is connected to the plurality of memory devices, and wherein the controller sequentially transfers data from the plurality of memory devices into the storage device.

32. The non-volatile memory module of claim 30, wherein the controller sequentially shuts off the power to each of the plurality of memory devices after it has been completely transferred into the storage device.

33. The non- volatile memory module of claim 30, wherein the controller transfers data from the plurality of memory devices into the storage device when the controller determines that an external voltage level is less than a predetermined level.

34. The non-volatile memory module of claim 30, wherein the controller transfers data from the plurality of memory devices into the storage device when the controller determines that an external voltage level is approaching a predetermined level.

35. The non-volatile memory module of claim 30, wherein the controller transfers data previously transferred into the storage device to the plurality of memory devices when the controller determines that an external voltage level exceeds a predetermined level.

36. The non-volatile memory module of claim 30, wherein the controller transfers data previously transferred into the storage device to the plurality of memory devices when the controller determines that an external voltage level is approaching a predetermined level.

37. A non-volatile memory module comprising: means for storing data; means for supplying unintermptible power to the means for storing; and means for controlling the means for storing and the means for supplying unintermptible power.

38. The non-volatile memory module of claim 37, wherein the means for controlling is embedded in the means for storing.

39. The non-volatile memory module of claim 37, wherein the means for controlling is a processing unit external to the non-volatile memory module.

40. The non-volatile memory module of claim 37, wherein the means for controlling is a system processing unit external to the non-volatile memory module.

41. The non- volatile memory module of claim 37, wherein the means for controlling is a disk controller.

42. The non-volatile memory module of claim 37, wherein the means for supplying uninterruptible power is a battery.

43. The non-volatile memory module of claim 37, wherein a storage device is connected to the means for storing, and wherein the means for controlling shuts down the means for supplying unintermptible power after the means for storing is completely transferred into the storage device.

44. The non- volatile memory module of claim 43, wherein the means for controlling transfers data from the means for storing into the storage device when the means for controlling determines that an external voltage level is less than a predetermined level.

45. The non- volatile memory module of claim 43, wherein the means for controlling transfers data from the means for storing into the storage device when the means for controlling determines that an external voltage level is approaching a predetermined level.

46. The non- volatile memory module of claim 43, wherein the means for controlling transfers data previously transferred into the storage device to the means for storing when the means for controlling determines that an external voltage level exceeds a predetermined level.

47. The non- volatile memory module of claim 43, wherein the means for controlling transfers data previously transferred into the storage device to the means for storing when the means for controlling determines that an external voltage level is approaching a predetermined level.

48. The non-volatile memory module of claim 37, wherein the means for storing further comprises a plurality of means for storing.

49. The non-volatile memory module of claim 48, wherein a storage device is connected to the plurality of means for storing, and wherein the means for controlling sequentially transfers data from the plurality of means for storing into the storage device.

50. The non-volatile memory module of claim 49, wherein the means for controlling sequentially shuts off the power to each of the plurality of means for storing after it has been completely transferred into the storage device.

51. The non- volatile memory module of claim 49, wherein the means for controlling transfers data from the plurality of means for storing into the storage device when the means for controlling determines that an external voltage level is less than a predetermined level.

52. The non-volatile memory module of claim 49, wherein the means for controlling transfers data from the plurality of means for storing into the storage device when the means for controlling determines that an external voltage level is approaching a predetermined level.

53. The non-volatile memory module of claim 49, wherein the means for controlling transfers data previously transferred into the storage device to the plurality of means for storing when the means for controlling determines that an external voltage level exceeds a predetermined level.

54. The non-volatile memory module of claim 49, wherein the means for controlling transfers data previously transferred into the storage device to the plurality of means for storing when the means for controlling determines that an external voltage level is approaching a predetermined level.

55. A computer system comprising: a plurality of non-volatile memory sub-systems, wherein each non- volatile memory sub-system comprises: at least one memory device; an uninterruptible power supply connected to at least one memory device; a storage device connected to at least one memory device; and a controller; wherein each of the non-volatile memory sub-systems are interconnected.

56. A computer system comprising: at least one non-volatile memory module, comprising: at least one memory device; an uninterruptible power supply connected to at least one memory device; a storage device connected to at least one memory device; and a controller; and a plurality of storage nodes, each of which is connected to at least one non- volatile memory module.

57. The non-volatile memory system of claim 56, wherein each of the plurality of storage nodes comprises: a storage device; and a controller.

58. A method for transferring data between a non- volatile memory module powered by an unintermptible power supply and a storage device in a computer system, comprising: determining if the voltage level of the computer system is less than a predetermined level; based on that determination, if the voltage level is less than a predetermined level, transferring data from the non-volatile memory to the storage device; and turning off the unintermptible power supply of the non-volatile memory module.

59. The method of claim 58, wherein the method further comprises: determining if the voltage level of the computer system is above the predetermined level following a shutdown of the unintermptible power supply; and based on that determination, turning on the uninterruptible power supply if the voltage level is above the predetermined level.

60. The method of claim 59, wherein the method further comprises transferring the data that was transferred into the storage device back to the non- volatile memory if the voltage level is above the predetermined level.

61. The method of claim 59, wherein the method further comprises transferring the data that was transferred into the storage device to a main storage device if the voltage level is above the predetermined level.

62. The method of claim 59, wherein the method further comprises transferring the data that was tiansferred into the storage device to a processing unit memory if the voltage level is above the predetermined level.

63. The method of claim 58, wherein the non- volatile memory comprises a plurality of memory devices and the data is sequentially transferred from each of the memory devices comprising the non-volatile memory to the storage device.

64. The method of claim 63, wherein power to each of the memory devices is sequentially shut off after each memory device is transferred to the storage device.

65. A computer program product for enabling a computer system to transfer data between a non-volatile memory module powered by an uninterruptible power supply and a storage device, the computer program product comprising: software instructions for enabling the computer system to perform predetermined operations, and a computer readable medium bearing the software instructions; the predetermined operations comprising: determining if a voltage level of the computer system is less than a predetermined level; based on that determination, if the voltage level is less than a predetermined level, flushing data from the non- volatile memory to the storage device; and turning off the uninterruptible power supply of the non- volatile memory module.

66. The computer program product of claim 65, wherein the predetermined operations further comprise: determining if the voltage level of the computer system is above the predetermined level following a shutdown of the uninterruptible power supply; and based on that determination, turning on the uninterruptible power supply if the voltage level is above the predetermined level.

67. The computer program product of claim 65, wherein the predetermined operations further comprise transferring the data that was tiansferred into the storage device back to the non-volatile memory if the voltage level is above the predetermined level.

68. The computer program product of claim 65, wherein the predetermined operations further comprise transferring the data that was transferred into the storage device to a main storage device if the voltage level is above the predetermined level.

69. The computer program product of claim 65, wherein the predetermined operations further comprise transferring the data that was transferred into the storage device to a processing unit memory if the voltage level is above the predetermined level.

70. The computer program product of claim 65, wherein the non- volatile memory comprises a plurality of memory devices and the predetermined operations further comprise sequentially transferring data from each of the memory devices comprising the non-volatile memory to the storage device.

71. The computer program product of claim 65, wherein the predetermined operations further comprise sequentially shutting off power to each of the memory devices after each memory device is transferred to the storage device.

72. A computer system for transferring data between a non- volatile memory module powered by an unintermptible power supply and a storage device, the computer system comprising: software means for determining if a voltage level of the computer system is less than a predetermined level; software means for, if the voltage level is less than a predetermined level, flushing data from the non-volatile memory to the storage device; and software means for turning off the unintermptible power supply of the non- volatile memory module.

73. The computer system of claim 72, further comprising software means for determining if the voltage level of the computer system is above the predetermined level following a shutdown of the unintermptible power supply, and, based on that determination, for turning on the unintermptible power supply if the voltage level is above the predetermined level.

74. The computer system of claim 72, further comprising software means for transferring the data that was transferred into the storage device back to the non-volatile memory if the voltage level is above the predetermined level.

75. The computer system of claim 72, further comprising software means for transferring the data that was transferred into the storage device to a main storage device if the voltage level is above the predetermined level.

76. The computer system of claim 72, further comprising software means for transferring the data that was transferred into the storage device to a processing unit memory if the voltage level is above the predetermined level.

77. The computer system of claim 72, wherein the non- volatile memory comprises a pluraUty of memory devices and the computer system further comprising software means for sequentially transferring data from each of the memory devices comprising the non-volatile memory to the storage device.

78. The computer system of claim 77, further comprising software means for sequentially shutting off power to each of the memory devices after each memory device is transferred to the storage device.

79. An executable program for a computer system for transferring data between a non-volatile memory module and a storage device, the executable program comprising: a first executable code portion which, when executed on a computer, determines if a voltage level of the computer system is less than a predetermined level; a second executable code portion which, when executed on a computer, if the voltage level is less than a predetermined level, transfers data from the non- volatile memory to the storage device; and a third executable code portion which, when executed on a computer, turns off the uninterruptible power supply of the non- volatile memory module.

80. The executable program for a computer system of claim 79, further comprising an executable code portion which, when executed on a computer, determines if the voltage level of the computer system is above the predetermined level following a shutdown of the unintermptible power supply, and, based on that determination, turns on the uninterruptible power supply if the voltage level is above the predetermined level.

81. The executable program for a computer system of claim 80, further comprising an executable code portion which, when executed on a computer, transfers the data that was transferred into the storage device back to the non-volatile memory if the voltage level is above the predetermined level.

82. The executable program for a computer system of claim 80, further comprising an executable code portion which, when executed on a computer, transfers the data that was transferred into the storage device to a main storage device if the voltage level is above the predetermined level.

83. The executable program for a computer system of claim 80, further comprising an executable code portion which, when executed on a computer, transfers the data that was transferred into the storage device to a processing unit memory if the voltage level is above the predetermined level.

84. The executable program for a computer system of claim 79, further comprising an executable code portion which, when executed on a computer, sequentially tiansfers data from each of the memory devices comprising the non-volatile memory to the storage device.

85. The executable program for a computer system of claim 84, further comprising an executable code portion which, when executed on a computer, sequentially shuts off power to each of the memory devices after each memory device is transferred to the storage device.