JPH1040176A - System and method for memory management of electronic equipment, and storage medium stored with memory management program that computer can read - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the life of a device by replacing memory blocks according to various conditions and devising a memory system so that their write frequencies are equally dispersed. SOLUTION: A divided storage area of a nonvolatile element 16 is provided with a corresponding management area, and the write frequencies of respective storage areas are integrated and recorded. To prevent print speed performance from decreasing, a CPU starts a confirmation program (ROM) for a write frequency in idle time when not print job is executed and there is no receive data, and replacement is performed if the difference between an area whose write frequency is minimum and an area whose write frequency is maximum exceeds a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a memory management system and a memory management method for electronic equipment, and a storage medium storing a computer-readable memory management program.

More specifically, the present invention relates to a microprocessor used in a personal computer or the like,
The present invention relates to a storage management mechanism of a nonvolatile storage element in a main storage device of various arithmetic elements such as a one-chip microcomputer and a digital signal processor used in various embedded devices.

[0003]

2. Description of the Related Art Generally, a storage device such as a computer has a main storage and a secondary storage.

The main memory is a device in which an arithmetic element can directly refer to data based on an address selection line from the arithmetic element, and a ROM for constantly storing instructions, data, and the like, and temporarily holds data. , Or a RAM that holds instructions, data, and the like read from the secondary storage.

The contents of the RAM can be freely rewritten, but the contents are lost when the power is turned off.

The ROM retains its contents even when the power is turned off, but cannot electrically rewrite the stored contents. R
The contents of the OM are set at the time of manufacture or at the time of shipment of a device incorporating a computer, and are not changed at the time of use.

The secondary memory is a device that is difficult to directly refer to only by the address selection signal from the arithmetic element, and requires a mechanical operation or takes a long time for random access. A device for which direct data reference is not practical. Generally, the contents are RAM
And then referred to by the arithmetic element.

[0008] The secondary storage generally has a large capacity at the cost of slower access than the main storage. Therefore, it is suitable for storing a large amount of data.

For example, a CDROM or the like is used as a fixed information storage location. In addition, when the stored contents are often changed and the written information needs to be stored even when the power is turned off, a device such as a magnetic disk is used.

Further, there is a case where a cache memory having a high access speed exists in order to make up for the slow access speed of the main memory to improve the operation speed of the arithmetic element.

In general, a computer is composed of the above-described storage element, input / output devices, and arithmetic elements.

As another storage element, there is an electrically rewritable semiconductor element.

The difference from a RAM is that its contents are not lost even when the power is turned off. Therefore, it can be used for retaining data. However, such an electrically rewritable semiconductor element has not been frequently rewritten frequently because of problems such as a small capacity, a low access speed, a complicated rewriting procedure, and reliability. It was only used to hold small amounts of information.

However, with the recent development of semiconductor technology, the storage capacity, access speed, content rewriting procedure, price, etc. of the above-mentioned electrically rewritable semiconductor element have been greatly improved. In addition, the rewriting life is increasing.

For this reason, a secondary storage device having a relatively small capacity,
Alternatively, it has been used as a primary storage device.

[0016]

Although such an electrically rewritable semiconductor element can be directly referred to by an address selection line like a main memory, it is not infinitely rewritable like a RAM. Always keep in mind.

Although the life of each element in the chip varies due to the variation in the semiconductor formation process,
The manufacturer guarantees a certain value as the worst case write count.

Therefore, in general, when such a nonvolatile memory element is used in a normal printing device or the like, it is necessary to give a sufficient margin to the life of the nonvolatile memory element.

In a printing apparatus in which such a storage element is mounted, the number of rewrites varies considerably depending on the purpose of use of the memory.

For example, an area set as an image development area may be written several times or more in printing one sheet.

On the other hand, in the character cache area where the outline character image data is expanded,
Since there is no need to worry about rewriting until the area is full and new characters need to be developed into images, frequently used characters and typefaces are not rewritten much. When a piece of text is printed, it is kept as it is.

Until printing of different qualities, such as English and Japanese, or text and graphics, for example, there is a high probability of being retained as is.

Further, the frequency of rewriting outline font information, a fixed format, and the like downloaded from the host decreases.

In view of the above, it is an object of the present invention to replace the memory blocks according to various conditions, and to devise a memory system so that the number of times of writing is evenly distributed. An object of the present invention is to provide a memory management system and a memory management method for an electronic device and a storage medium storing a computer-readable memory management program, which can be extended.

Here, as the above various conditions, if the phenomenon occurs at appropriate intervals in practical use,
Regardless of its type. For example, paper supply, power-on, and the like are also set as start conditions.

[0026]

In order to achieve the above object, a memory management system according to the present invention is a memory management system using a nonvolatile storage element included in an electronic device as a main storage device. And a dividing unit for dividing the nonvolatile memory element into a plurality of regions, and a switching unit for replacing the plurality of divided regions with each other. Here, the main storage device is referred to based on information on an address signal line output from a microprocessor or another arithmetic element. It is preferable that a printing device is configured as the electronic device. The nonvolatile memory element is an element that can write information to a memory cell at the same position a plurality of times, and can partially or collectively electrically rewrite all memory cells of the element. Yes, it is an element that retains the stored contents even when the power supply is cut off.

The above dividing means divides the nonvolatile memory element into a plurality of areas and provides an attribute area for each area.

The replacement means has means for obtaining the number of times of writing to each of the plurality of divided areas as a constituent element, and is obtained by performing predetermined arithmetic processing on a numerical value notified by the means. Operate based on the result. Alternatively, the replacement means has a means for obtaining time information as a component, and operates based on a result obtained by performing predetermined arithmetic processing on the time information notified by the means. Alternatively, the replacement means includes a counting means for counting the number of printed sheets, and operates based on a result obtained by performing a predetermined arithmetic processing on a value notified by the counting means. Alternatively, the replacement means operates based on a result obtained by performing predetermined arithmetic processing on the information of the attribute area.
Here, the arithmetic processing is executed by a built-in control device.

In the memory management method according to the present invention, when the nonvolatile storage element included in the electronic device is used as a main storage device, the nonvolatile storage element is divided into a plurality of areas, and the divided plurality of areas are divided. Regions are interchanged.

Further, a storage medium storing a computer-readable memory management program, characterized by storing the above-mentioned memory management method as a program, can be constituted.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the present invention, a non-volatile storage element (this storage element is used as a main storage referred to based on information on an address signal line from an arithmetic element such as a microprocessor or the like). A description will be given of a storage management mechanism in a printing apparatus that includes the above configuration.

Here, the nonvolatile storage element, which is a component of the storage device, is an element capable of writing information to a storage cell at the same position a plurality of times, and partially rewrites all storage cells of the element. It can be electrically or collectively performed electrically, and is defined as an element that retains stored content even when power supply is cut off.

This nonvolatile memory element is divided into a plurality of areas, and each area is further provided with an attribute area. And it has a mechanism for exchanging a plurality of divided areas.

The above replacement mechanism has a mechanism for obtaining the number of times of writing to each area as a constituent element, and operates based on the result of arithmetic processing of the notified numerical value by the control mechanism.

A mechanism for obtaining time information is provided as a component,
It operates based on the result of arithmetic processing of the notified time information by the control mechanism.

The printing mechanism has a means for counting the number of printed sheets as a component, and operates based on the result of arithmetic processing by the control mechanism on the value reported by the counting means.

The operation is performed based on the result of arithmetic processing of the information of the attribute area by the control mechanism.

[0038]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a main configuration of a first embodiment of the present invention.

Reference numeral 10 denotes an interface with a host such as a personal computer, which receives print information and sends back various statuses.

Reference numeral 11 denotes an interface with a printing structure, which outputs a printing image in accordance with the operation of the printing mechanism.
Receives the status of the printing mechanism.

Reference numeral 12 denotes a printing mechanism.

Reference numeral 13 is a CPU.

Reference numeral 14 denotes a RAM.

Reference numeral 15 denotes a ROM.

Reference numeral 16 denotes an electrically rewritable nonvolatile element. The address line and the data line are directly connected to the bus line 100 without going through the I / O.

Reference numeral 101 denotes a connection line between the printing mechanism and the image forming unit.

An interface signal line 102 connects an external device such as a personal computer to a printing mechanism.

FIG. 1 is not much different in structure from the image forming section of the conventional printing apparatus. The difference is that an electrically rewritable nonvolatile element is added in addition to the RAM and the ROM.

The write timing generation mechanism for the flash memory differs depending on the manufacturer and is not unified, so that it is not shown.

In the first embodiment, a corresponding management area is provided for each of the divided storage areas of the non-volatile element, and the number of times of writing in each storage area is integrated and recorded, thereby preventing a reduction in printing speed performance. In the idle time when the print job is not executed and there is no received data, the program for confirming the number of times of writing is started, and when the difference between the area of the minimum number of times of writing and the area of the maximum number of times exceeds the specified value, The configuration for performing the replacement is shown.

FIG. 2 shows a configuration of the nonvolatile element 16 according to the first embodiment. The nonvolatile element 16 is first divided into a management area X and a data area Y, each of which is further divided into N pieces. X _i of the management area is initially at data area Y
Corresponding to _i , various attributes are registered in the management area. In the present embodiment, the address information X _pi of the data area corresponding to the management area and the write count information X
Indicates _ci as an attribute.

In consideration of the life of the nonvolatile element and the printing mechanism, an area of 3 to 4 bytes is sufficient as the information on the number of times of writing. However, since the information on the number of times of writing is the most frequently rewritten information, Life may come earlier. For this reason, it is not used as a simple counter, but an area of several tens of bytes is secured, and a conversion algorithm of a numerical value and a storage pattern that distributes writing is prepared.

The replacement of the area is realized by rewriting the address information _Xpi in the management area.

The method for exchanging areas and the starting mechanism for exchanging areas can be arbitrarily combined with each embodiment described later. Further, the activation mechanism of the area replacement can be a combination of a plurality of conditions.

FIG. 3 shows an algorithm (RO) of the program according to the present invention, which is added as an idle job.
M stored in M).

After confirming that the reception buffer is empty,
The PU starts the execution program of the present invention. The activated execution program operates the interface 10 to change the interface signal line 102 to the BUSY state,
Start internal processing. Search all X _ci management area, detecting the maximum value X _Cimax and the minimum value _X cimin. If the difference between the maximum value and the minimum value is less than the specified value, the process ends without performing any operation.

If the value is equal to or larger than the specified value, the address information X
replacing the data of Y _i area indicated by the _pimax and _X pimin,
The contents of the address information X _pimax and X _pimin are exchanged.

At the time of normal reading and writing with respect to the i area of the nonvolatile element, the X _pi information of the corresponding management area is read once, and reading and writing is performed with respect to the area indicated by X _pi . At the time of writing, X _ci is updated.

FIGS. 4 and 5 show a normal read / write procedure for area i.

In FIG. 3, step a1 indicates the start of the program.

At step a2, it is determined whether or not the reception buffer is empty.

In step a3, variables X _max and X _min are prepared (i = 1).

[0064] In step a4, X _ci is the greater than X _max is substituted into X _max, is stored as X _Cimax.

[0065] In step a5, X _ci is if X _min smaller by substituting the X _min, and stored as _X cimin.

At step a6, i = i + 1 is set.

At step a7, it is determined whether or not i> n.

In step a8, X _cimax -X
_It is determined whether _cimin is larger than a specified value.

At step a 9, the contents of the Y _j1 area indicated by X _pimax are saved in the RAM 14.

In step a10, Y _j2 indicated by X _pimin
Transfer the contents of the area to Y _j1 .

At step a11, the contents of Y _j1 saved in the RAM 14 are transferred to the Y _j2 area.

In step a12, X _pimax and X _pimin1
Replace the contents of

At step a13, the process ends.

In FIG. 4, the process starts at step b1.

[0075] In step b2, to search the area X _i.

[0076] In step b3, to find the X _pi of the region of interest.

At step b4, Y _k indicated by X _pi is searched.

At step b5, data is read.

In step b6, the process ends.

In FIG. 5, the process starts at step c1.

[0081] In step c2, to search the area X _i.

[0082] In step c3, to find the X _pi of the region of interest.

In step c4, Y _k indicated by X _pi is searched.

At step c5, a data writing process is performed.

[0085] In step c6, to update the value of X _pi.

At step c7, the process ends.

(Second Embodiment) In the second embodiment, a configuration is adopted in which a clock module is held as a constituent element, and the divided nonvolatile storage areas are regularly replaced at predetermined time intervals. Show. Although the verification of the exact number of times of writing is not performed, the software configuration is simple.

The area exchange mechanism is realized by preparing a memory management unit and electrically converting the address information. By realizing replacement by hardware, data can be read directly without referring to the management area.
This is advantageous in effective speed.

As the management area, it is only necessary to store at least address information for the memory management unit when the power is turned off.

FIG. 6 shows a main configuration according to the second embodiment of the present invention. In the present embodiment, a memory management unit (MMU) 17 on the bus line is added, and at least the nonvolatile element 16 is accessed via the MMU 17. Whether or not the RAM 14 and the ROM 15 pass through the MMU 17 is a problem different from the present invention, and will not be described.

The MMU 17 includes n registers R _i for address designation corresponding to the data area.

When the printing apparatus is initialized, the physical address output from the CPU 13 matches the output from the MMU 17. First, X _pi is read as an initialization job, and MM
U17 is set, and the data on the nonvolatile element 16 is arranged at the correct address. FIG. 7 shows an initialization job (stored in the ROM) executed by the CPU.

In FIG. 7, the process starts at step d1.

At step d2, i = 1 is set.

[0095] At step d3, writing X _pi value in the i-th register of MMU17.

At step d4, i = i + 1 is set.

At step d5, it is determined whether or not i> n.

In step d6, the process ends.

Normal reading / writing is performed by using ROM or RA.
It is omitted because it is the same as M.

When managing the number of times of writing as seen in the first embodiment, the MMU 17
X _ci is updated by the job started by the interrupt signal 103 in which the error occurs.

The job sequence to be started is shown by the broken line in FIG.

In FIG. 8, the process starts at step e1. In step e2, the write occurrence area is determined.

At step e3, X _ci of the target area is searched.

At step e4, the value of X _ci is updated.

At step e5, a data write process is performed.

At step e6, the value of X _pi is updated.

At step e7, the clock module 1
Read the value of 8.

At step e8, the clock module 1
It is determined whether or not the value of 8 has reached the specified period T.

At step e9, the specified period T is reset.

At step e10, the process jumps to the process of FIG.

In step e11, the process ends.

However, the counting process of the broken line portion shown in FIG. 8 is not required in the second embodiment. Therefore, in this embodiment, the interrupt signal 103 is not necessary.

In FIG. 8 itself, the setting of the program activation by hardware processing using the interrupt signal 104 is not necessary.

In the startup detection by software, a startup is determined by preparing a variable T on the management area and comparing it with a read value. At startup, T is updated appropriately,
Prepare for the next startup decision.

The time information of the clock module 18 is notified to the CPU in hardware by an interrupt signal,
Alternatively, it is used as a start signal of the area replacement program by pure software such as an initialization sequence at power-on.

FIG. 9 shows a sequence (stored in the ROM) after startup, which is executed by the CPU. When driven by hardware, the signal line 104 exists without including the processing in the wavy frame. This sequence is used as one of interrupt processing.

In FIG. 9, the process starts at step f1.

In step f2, R1 and the reference area of R1 are saved. At step f3, i = 1.

[0119] In step f4, the R _i reference region R1 +
The data in the reference area 1 is copied.

In step f5, the value of R1 + 1 is copied to R _i .

At step f6, i = i + 1 is set.

At step f7, it is determined whether or not i> n.

[0123] In step f8, copying the saved data of the reference region of the R1 to R _n reference area.

In step f9, the R saved in R _n
Copy the value of 1.

[0125] In step f10, writes back a value of R to X _p.

At step f11, the process ends.

On the other hand, when the processing is executed only by software, the start sequence of the software in the broken line portion is included, and the interrupt signal 104 does not exist. Then, the initialization sequence is performed.

As a result, the clock module 18 drives the area replacement program at specified time intervals.

[0129] area swapping process after startup, copies the region Y _i in region Y _{i + 1.}

Although not required in the present embodiment, if the area is replaced by software as in the first embodiment, the value of X _{pi in} the management area is replaced with X _{pi + 1} . That is, resetting is performed by shifting all the regions one by one.

(Third Embodiment) In the third embodiment, there is shown a configuration in which a mechanism for integrating the number of prints is provided, and a nonvolatile storage area divided for each fixed number of prints is regularly replaced. . Although accurate verification of the number of times of writing to the non-volatile element is not performed, leveling of the number of times of writing to each area can be expected, and there is no need to separately provide a management area, so that the software configuration can be simplified.

The area exchange mechanism is omitted.

As the management area for replacing the areas, it is only necessary to store the information on the number of printed sheets Z at least when the power is turned off.

The main configuration in the third embodiment is as follows.
This is the same as in the first embodiment. No special hardware is required. In the present embodiment, the print number information Z only exists as a single parameter independent of the number of areas on the management area.

Each time the printing output is completed, the start-up sequence (stored in the ROM in the form of a program) of the print number measurement process and the area replacement program based on the integrated value of the print number, which are features of the present embodiment, is shown in FIG. Shown in

In FIG. 10, the process starts at step g1.

At step g2, the value of Z is read.

At step g3, Z = Z + 1.

At step g4, the value of Z is written back.

At step g5, it is determined whether or not the value of Z has reached the specified number.

At step g6, Z = 0 is set.

At step g7, an area exchange process is executed.

At step g8, the process ends.

Although there are many printing devices having a mechanism for recording the total number of printed sheets, in the present invention, Z is an independent variable, and is intended only for flattening the number of times of writing in the nonvolatile storage element.

Z is counted up to the number of printed sheets, and when the value exceeds a specified value, the area replacement program is driven.

[0146] area swapping process after startup, copies the region Y _i in region Y _{i + 1.} That is, resetting is performed by shifting all the areas one by one.

The total number of printed sheets and Z can of course be used together. However, resetting the value of the total number of printed sheets causes a problem.
In addition to the variable for counting the number of printed sheets, it is necessary to prepare a variable, and eventually two variables are required. Therefore, in this embodiment, the configuration using Z alone is shown.

(Fourth Embodiment) In the embodiment of FIG. 4, a configuration is shown in which a nonvolatile storage area divided as one of startup jobs at power-on is regularly replaced. According to the present embodiment, it is expected that the number of times of writing to each area of the nonvolatile element can be leveled, and it is not necessary to provide a management area individually and no special hardware is required.
The software configuration is simple.

The description of the area exchange mechanism is omitted.

The main configuration in the third embodiment is as follows.
This is the same as in the first embodiment. No special hardware is required. In this embodiment, no special management area is required.

As part of the initialization sequence, FIG.
The area is forwarded as shown in FIG.

[0152]

As described above, according to the present invention, a product having a longer life can be provided by maximally and effectively utilizing the life of an electrically rewritable semiconductor device such as a flash ROM. It is possible to provide a lower cost product.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration on a nonvolatile element 16 according to the first embodiment.

FIG. 3 is a flowchart showing an algorithm of an execution program according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a normal reading procedure for an area i.

FIG. 5 is a flowchart showing a normal writing procedure for an area i.

FIG. 6 is a block diagram showing a main configuration according to a second embodiment of the present invention.

FIG. 7 is a flowchart illustrating an initialization job according to the second embodiment.

FIG. 8 is a flowchart showing a start-up sequence of an execution program at the time of software processing in the second embodiment (a broken line shows a sequence at the time of managing the number of times of writing).

FIG. 9 is a flowchart illustrating an area replacement sequence after activation according to the second embodiment.

FIG. 10 is a flowchart illustrating an activation sequence of an area replacement program according to the third embodiment.

[Explanation of symbols]

Reference Signs List 10 Interface with host 11 Interface with printing mechanism 12 Printing mechanism 13 CPU 14 RAM 15 ROM 16 Electrically rewritable nonvolatile element 17 MMU 18 Clock module 100 Bus line 101 Connection line between printing mechanism and image forming unit 102 External device Interface signal line 103 connecting to an example of the embodiment of the present invention 103 Interrupt signal from MMU 104 Interrupt signal from clock module 18 X Data in management area Subscript p Address information in subscript Subscript c Numerical information Y Data area R Register for addressing in MMU n Number of areas

Claims (21)

[Claims] 1. A memory management system using a non-volatile storage element included in an electronic device as a main storage device, comprising: a dividing unit that divides the non-volatile storage element into a plurality of areas; A memory management system in an electronic device, comprising: a replacement unit for replacing a plurality of areas with each other. 2. The storage device according to claim 1, wherein the main storage device comprises:
A memory management system in an electronic device, which is referred to based on information on an address signal line output from a microprocessor or another arithmetic element. 3. The memory management system according to claim 1, wherein a printing device is configured as the electronic device. 4. The nonvolatile memory element according to claim 1, wherein the nonvolatile memory element is an element capable of writing information to a memory cell at the same position a plurality of times, and partially or collectively rewrites all memory cells of the element. A memory management system for an electronic device, wherein the memory management system is an element that can store data even when power supply is shut off. 5. The memory management system according to claim 1, wherein the dividing unit divides the nonvolatile memory element into a plurality of areas and provides an attribute area for each area. 6. In any one of claims 1 to 5,
The replacement means has, as a component, means for obtaining the number of times of writing in each of the plurality of divided areas, based on a result obtained by performing predetermined arithmetic processing on a numerical value notified by the means. A memory management system in an electronic device that operates. 7. The method according to claim 1, wherein
The electronic device according to claim 1, wherein the replacement unit has a unit that obtains time information as a component, and operates based on a result obtained by performing predetermined arithmetic processing on the time information notified by the unit. Memory management system. 8. The method according to claim 1, wherein
The replacement means has a counting means for counting the number of printed sheets as a component, and operates based on a result obtained by performing a predetermined arithmetic processing on a value notified by the counting means. Memory management system in electronic equipment. 9. The memory management system according to claim 5, wherein the replacement unit operates based on a result obtained by performing predetermined arithmetic processing on the information of the attribute area. 10. The memory management system in an electronic device according to claim 6, wherein the arithmetic processing is executed by a built-in control device. 11. When using a nonvolatile storage element included in an electronic device as a main storage device, the nonvolatile storage element is divided into a plurality of areas, and the plurality of divided areas are replaced with each other. A memory management method in an electronic device, comprising: 12. The memory management method according to claim 11, wherein the main storage device is referred to based on information on an address signal line output from a microprocessor or another arithmetic element. 13. The memory management method according to claim 11, wherein a printing device is configured as the electronic device. 14. The nonvolatile memory element according to claim 11, wherein the nonvolatile memory element is an element capable of writing information to a memory cell at the same position a plurality of times, and partially or collectively rewrites all memory cells of the element. A memory management method for an electronic device, wherein the element is a device that retains stored contents even when power supply is cut off. 15. The memory management method in an electronic device according to claim 11, wherein, in the step of dividing, the nonvolatile storage element is divided into a plurality of areas, and an attribute area is provided for each area. . 16. The method according to claim 11, wherein, in the step of performing the replacement, the number of times of writing into each of the plurality of divided areas is obtained, and a predetermined number of times is obtained based on the obtained number of times. A memory management method in an electronic device, which performs an arithmetic process. 17. The electronic device according to claim 11, wherein in the step of performing the replacement, time information is obtained, and a predetermined calculation process is performed based on the obtained time information. Memory management method for devices. 18. The method according to claim 11, wherein in the step of performing the replacement, the number of printed sheets is counted, and a predetermined calculation process is performed based on the counted value. Memory management method for electronic devices. 19. The memory management method in an electronic device according to claim 15, wherein in the step of performing the replacement, a predetermined calculation process is performed based on the information of the attribute area. 20. The memory management method according to claim 16, wherein the arithmetic processing is executed by a built-in control device. 21. A storage medium storing a computer-readable memory management program, wherein the memory management method according to claim 11 is stored as a program.