KR101107288B1 - multi-partitioned flash memory device and dual journaling store method for storing data in partitioned memory - Google Patents

Abstract

The present invention relates to a method of storing data in each partition of a flash memory in which partitions are divided into a plurality of partitions, and data can be written, read or deleted for each partition.

One type of data is stored in a journaling manner from the first position of the storage medium, and the other type of data is stored in a journaling manner from the end position of the storage medium in the first direction.

According to the present invention, since the same type of data is kept in a certain area, it is possible to achieve fast data access time, and also, when a data error occurs due to a power failure according to the characteristics of the journaling storage method, the data to the previous version Ease of recovery has the effect of ensuring the reliability of the data.

Description

Multi-partitioned flash memory device and dual journaling store method for storing data in partitioned memory}

1 illustrates a conventional flash memory device.

2 is a view showing an example of a storage method in JFFS2 constituting a file system in a general flash memory.

3 illustrates a flash memory device multi-divided by the present invention.

4 is a diagram illustrating an embodiment in which the heads of the first half journaling and the second half journaling meet each other to determine a center point in a dual journaling storage method according to the present invention.

5 is a view illustrating an embodiment of a process of determining a new center point by first increasing the head of the rear half journaling and then meeting the center point and moving the center point toward the front half journaling in the dual journaling storage method according to the present invention.

Figure 6 is a flow chart showing the overall performance of the dual journaling storage method of the present invention.

7 is a flow chart illustrating garbage collection (GC) performance as part of the dual journaling storage method of the present invention.

8 is a graph for determining the number of blocks erased in the GC of the dual journaling storage method of the present invention.

9 is a diagram illustrating an embodiment of a triple segment flash memory device according to the present invention;

 10 is a diagram showing an example of a mobile terminal using the flash memory device according to the present invention.

Explanation of symbols on the main parts of the drawings

H1: First half head H2: Second half head

T1: first half tail T2: second half tail

C: center point

In the present invention, when a flash memory and a hard disk are used as storage media for storing, managing, and processing data, a multi-partitioned file system that employs the file system is employed for each partition. The present invention relates to a flash memory device, a portable terminal, and a dual journaling storage method for storing data in each partition.

With the recent development of the information industry and mobile computing technology, many personal digital assistants (PDAs), hand-held PCs (HPCs), mobile phones, e-books, etc. have been developed for the purpose of storing data therein. It uses a lot of flash memory that is easy to carry, has fast access time, and requires low power.

Flash memory has different characteristics from normal random access memory (RAM). Flash memory is non-volatile and robust compared to hard disks. It can operate at low power and has fast access times similar to RAM. Its small size makes it ideal for mobile devices.

However, it is 5-10 times more expensive than a hard disk, and there is a disadvantage in that when a new data is written to an already existing space, it can be stored again after a cleaning process.

Based on 28F640J3A model flash memory developed by Intel co., Ltd., the read speed is 100 ~ 150 nsec (nanosecond), which is similar to RAM, but the write speed and erase speed are relatively slow. The write time using a buffer takes about 218 μsec (microseconds) when using a 32byte buffer, and the write time in an erase block takes about 0.8 sec per block. In addition, the size of the erase block that can be deleted at one time is constant at 128 Kbytes, and the number of times that can be erased and reused at room temperature is set to about 100,000 times. The space in the flash memory that can be erased at one time is called an erase block or segment.

Flash memory can be classified into NOR, NAND, AND type according to the structure of a cell, but mainly NOR or NAND flash memory is used. NOR flash is used primarily for the purpose of storing code executed by the CPU directly connected to the memory address space due to the fast read speed and random access of random access, while NAND flash is relatively slow. Because of random access time, it is mainly used for storing relatively large data such as music file or image file at once.

That is, the flash memory is a special form of Electrically Erasable Programmable Read Only Memory (EEPROM) that can be written and erased in blocks instead of one byte at a time.

Some application areas of flash memory include the embedded control code and data of the mobile phone so that the flash memory can be easily updated if necessary. Flash memory is also used in modems because modem manufacturers can support new protocols with flash memory as new protocols become standardized.

Flash memory is also used in computers to provide upgradeable basic input / output systems (BIOS).

1 is a diagram illustrating a conventional flash memory device 100.

Referring to FIG. 1, the memory 110 in which data is written has an X-decoder 160 and a Y-decoder 180 associated therewith. X-decoder 160 and Y-decoder 180 allow address allocation of rows and columns of memory.

In addition, the user interface 120 controls the flash memory device 100. The user interface 120 is connected with a processor that controls access to the memory 110, and a status register 130 stores the state (write, read or delete) of the current memory 110. The processor knows the state of the flash memory from the user interface 120.

Also, sense amplifiers 140 are associated with memory 110, which is used to amplify a signal for writing or reading to memory 110. For example, for a column divided into sixteen inputs / outputs (I / Os), one for each I / O is used so sixteen sense amplifiers 140 are used for writing and reading.

In addition, a charge pump 150 is further included in the flash memory 100, which provides a voltage level necessary for writing, reading, and erasing the memory 110. Used.

In general, a conventional flash memory device is composed of one subset of memory 110 to be written and erased in one block. A user can write to a block of flash memory while simultaneously deleting or reading another block of memory. none.

However, simultaneous operation is required in some application techniques that are limited by the erase time of the flash memory block (typically 250-500 ms). For example, the mobile phone executes code directly from flash memory. This has the advantage that at the same time it is possible to delete a separate block of memory to use space for data storage.

One prior art solution to this problem is to have a plurality of flash memory devices, which can be written to one device while the other device is being deleted.

However, this has the disadvantage of taking up a large area. In other words, since a plurality of devices exist, hardware is duplicated. In addition, the use of multiple flash memory devices is expensive, increases power usage, and lowers overall system reliability.

Next, the prior art of constructing a file system using such a flash memory is a patent entitled Flash File System of US Patent No. 5,404,485, and A Flash Memory Based published on page 155 to 164 of the 1995 USENIX conference. There is a paper titled File System.

In addition, the log space file system invented in Journal space release for log-structured storage systems of US Pat. No. 6,128,630 and Data storage library array with log-structured file system which allows simultaneous write and garbage collection of US Pat. No. 6,128,630. There is a prior art of a journaling flash file system (JFFS) that applies a structured file system to a flash memory. A log system file system sequentially stores data generated when a file system is configured and stored on a hard disk. By doing so, you can maintain versions of old and newly modified data in log format, and you can recover by returning to the previous data for the current problem.                         

JFFS uses a log-structured file system to configure the file system for flash memory and to store the data in sequence.

JFFS was developed by Axis Communications, Inc. (http://developer.axis.com/software/jffs/) in the United States, and version 2 was developed by RedHat, Inc. (http://sources.redhat.com/jffs2/). Is being developed under the GNU Public Licenses (GPL) of the Free Software Foundation (FSF). 2 is a view illustrating an embodiment of a storage method in JFFS2 constituting a file system in a flash memory.

Referring to FIG. 2, this shows one example in which data is stored in a flash memory in the JFFS. In some file systems, for example when there is a directory structure in the EXT2 file system on Linux, the way it is stored in the JFFS is a directory, as in (a) of FIG. 2 to capture the general characteristics of a directory first. Save the entry (Dir 1 entry). The information stored therein is the type of the directory node, the total length of the node, the cyclic redundancy check (CRC) of the head, the parent inode number, the version value, the node CRC, the name CRC, and the directory name.

Immediately afterwards we store the inode for that directory. In FIG. 1, a Dir 1 inode is illustrated, and information stored therein is node type, total length, various types of CRC, version value, user ID, group ID, creation time, access time, modification time, and the like.

The above directory entries and inodes are additional information that is used only by the file system, not the information that is visible to the user. This is called metadata. When you save a file in a directory, you save a file entry (File 1 entry) and a file inode (File 1 inode), just like a directory.

The directories and files are viewed in the same format in the file system, except that the directory has no actual data, and in the case of a file, the file data (File 1 data) is stored after the inode.

In this way, JFFS uses a method of journaling directories and files for flash memory.

As shown in (b) of FIG. 2, when the Dir 1 inode and the File 1 inode are changed and updated to a new value, the original metadata is invalidated, and the new data is sequentially stored in the storage location. At this time, the invalidation state does not actually delete the data, but merely marks it as unnecessary data, and the version value of the new data is increased by one step. Therefore, if there is a problem with the new data, it is easy to recover as long as there is data from the previous version.

When the data is updated and new data is stored, the flash storage space reaches its limit and the flash memory must be deleted to secure the storage space. However, the flash memory must be deleted only in erase blocks. As shown in (c) of FIG. 2, when the valid data (Dir 1 entry) is moved and the erase block is filled with invalid spaces, the erase process is performed as shown in (d) of FIG. 2 to erase one erase block.

Garbage Collection (GC) is a process in which invalid space is collected due to lack of storage space, and then new blocks are deleted by erasing blocks. In addition, a space for storing new data created by the erasing process is called a free space. Now that you have a lot of free space, you can continue to store your data.

When using a hard disk as a storage medium, it is stored in a similar manner. However, in order to secure space, the hard disk does not move invalid data and make an invalidation block with an erase block size.

However, in order to speed up access to a file on a hard disk, there are cases where multiple pieces of the same file are collected and moved to physically neighboring locations. The hard disk does not need to be erased, so if the space to store new data is invalid, save it immediately. As the JFFS storage method proceeds, the entry and inode locations are mixed with the data of the file, and thus, when the flash memory is connected to the operating system and mounted to form a file system, the tree In order to create a directory structure in memory, there is a problem in that the directory structure can be configured by reading all the space of the flash memory and finding metadata.

The same problem occurs when configuring a log file system or a journaling file system using a hard disk instead of a flash memory. In other words, you don't need to move data to fit erase blocks like flash memory, but if metadata is mixed with file data and scattered throughout the space, access speeds are 40-50 times slower than flash, and gigabytes of capacity. Configuring a file system by reading the entire disk at an oversized size can be very time consuming. In addition, using a log file system or a journaling file system for a hard disk is mainly used to store and play a large amount of multimedia data. However, there is a disadvantage that the utility as a file system for multimedia is inferior.

In order to solve this problem, the present invention includes a plurality of partitions in a flash memory device to allow a read operation during writing, and each partition can be read, written, and deleted along with other partitions. For data stored in each partition of flash memory, it is separated from the metadata and general file data so that the file data is stored from the storage medium, i. The purpose of the present invention is to provide a dual journaling storage method.

Flash memory device according to the present invention for achieving the above object,

Multiple partitioned memory; A plurality of partitions separated by multiple divisions of the memory, in which data to be stored can be written, read or deleted independently; A charge pump providing a plurality of voltage outputs for outputting voltages for writing, reading and erasing; A plurality of first sense amplifiers comprising a plurality of first sense amplifiers for read operations in which each partition is executable at the same time and at least one sense amplifier for erase and write operations in which each partition is executable simultaneously;                         

The data stored in each partition is stored toward the center from the first position and the end position of the storage space of each partition.

In addition, the portable terminal according to the present invention includes the multi-divided flash memory device, and includes various buses and a processor connected to the buses. In this case, the multi-divided flash memory is connected to the bus and accessible by the processor.

In addition, the dual journaling storage method for storing data in the divided memory according to the present invention for achieving the above object stores the metadata in the storage medium, that is, from the first position to the end direction of each partition of the flash memory device, This includes storing the file data in the first direction from the end position.

Here, the data stored from the beginning of each partition and the data stored from the end to the first direction may be data of information other than metadata or file data.

In the dual journaling method of the present invention, one type of data is stored from the beginning for each partition of the flash memory device, and the other type is stored from the end to the front.

Data stored from the beginning is called front journaling data, and data stored from the end to the front is called rear journaling data. The location where the storage occurs is called the head, and the location where the deletion process is performed at the back of the journaling is called the tail. That is, the head and tail of the first half journaling and the head and tail of the second half journaling. In addition, the point where the head meets in the first half and the second half is called the center point.

When data to be stored enters the file system of each partition of the flash memory device, the storage medium needs space to physically store the data and space to store metadata such as file entries and inodes necessary to form a file for the data. .

In this case, the data in the file can be stored in the first half journaling, and the metadata can be stored in the second half journaling. The opposite is also true. That is, the data of the file is stored from the first half of the storage device, and the metadata is stored from the second half of the storage device. However, this may be the opposite.

As described above, when the arbitrary data is to be stored in the storage medium, the dual journaling storage method of the present invention determines which data to store and starts storing. When the data is updated, the old data is invalidated and the new data is stored at the head position. When the deletion of data occurs, it is only necessary to invalidate the data. If this storage, update, and deletion is repeated, the first and second journaling meet and center points for the storage medium.

If both the first half and the second half return to the initial position and continue processing the data, then either the head of the first half or the head of the second half meets the center point first, in which case there is a lot of data to store in the first journaling. Push the points to the other side to get more journaling on the data-rich side.

In the case of flash memory, one of the purposes of using the journaling storage method is to distribute the erase count of erased blocks evenly. Moving the center point increases the journaling of the data-rich side, and thus the erase count of the first half and the second half. You can arrange evenly.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 shows a flash memory device multi-divided by the present invention.

Referring to FIG. 3, partitions A 210, B 215, C 225, D 220, E 230,... N-1 235, n 235 are shown.

Each partition is implemented as a device physically partitioned into a flash memory device. In one embodiment, each partition is implemented in a different physical layer. Each partition 210, 215, 220, 225, 225, 230, 235, and 240 is associated with an X decoder and a Y selector.

Each Y selector is connected to a Y decoder 240 that controls the Y selector. As another example, a plurality of Y decoders 240 may be present in the system.

The X decoder and Y selector allow selection of a particular area within flash memory 200 for access including reading, writing and erasing. By configuring multiple X selectors and Y selectors, one or more subsections of flash memory can be accessed simultaneously.

For example, reading of partition B and writing of partition C are performed simultaneously while partition A is deleted. Each partition can contain one or more blocks that can be deleted separately. Thus, for example, while the memory block of partition B is deleted, it can be written to the memory in partition A.

The user may control access to the flash memory 200 through the user interface 250. In one embodiment, the user interface 250 is part of the flash memory itself. In another embodiment, the user interface 250 is located on a separate chip. The interface includes a plurality of state machines used to control each parallel write operation.

Thus, if there are two parallel write operations (eg, writing to a data block while updating code), there are two state machines. If there are three parallel write operations, there are three state machines.

State registers are coupled to the user interface 250. Status register 260 indicates the status of each partition. If there are n partitions, there are n state registers 260 as one embodiment. The state of each partition can be one of the following: idle, being read, being written, or being erased.                     

In addition, sense amplifiers 270 are connected to the user interface 250. Sense amplifiers are used for read, write and erase operations.

In one embodiment, the number of sense amplifiers 270 is determined as follows. That is, in a 16-bit wide flash memory, 16 sense amplifiers 270 are required for each executable parallel operation. Thus, for example, if the first partition is read while the second partition is being written, 32 sense amplifiers 270 are needed.

In addition, 32 sense amplifiers 270 are required for reading when two partitions are read in parallel. The number of sense amplifiers 270 is an element of the product of the width X of the output column of the flash memory and the number Y of parallel operations that can be performed.

As an example, in the case of triple partition flash memory, the first partition can be read, the second partition can be written, and the third partition can be deleted, in which case 3X detections. Sense amplifiers 270 are used. Sense amplifiers 270 used for erasure use a very low rate in total erase time.

Similarly, sense amplifiers 270 used for writing use a low rate in the total writing time. Thus, as an example, one sense amplifier 270 is used for each executable parallel write operation and each executable parallel erase operation.

Sense amplifier 270 is used to verify each bit as it is written. In addition, sense amplifiers 270 may be included for other operations, such as redundant column access.

In one embodiment, for each parallel read and / or write, two redundant sense amplifiers 270 are included in the sense amplifier block 270.

Furthermore, charge pumps 280 are included in the circuit. Charge pumps 280 are used to adjust voltage levels for reading, writing, and erasing. In one embodiment, the voltage level required for deletion is about -10 volts.

In one embodiment, the voltage level required for reading and writing is about 7 volts. In one embodiment, one charge pump 280 having a plurality of leads is used to allow parallel access to partitions.

As another example, a plurality of separate charge pumps 280 may be used to provide the voltage levels needed to access different partitions at the same time.

Charge pumps 280 are connected to the Y selectors of each partition to raise the voltage level to a level suitable for reading, writing, and deleting.

When the memory of the flash memory device, that is, the flash memory is multi-divided as described above, each divided partition can independently write, read, and delete, and accordingly, the data stored in the partition is also for each partition. It will be stored independently.

The present invention uses a dual journaling storage method in storing data in each partition, and describes a dual journaling storage method of the data as follows.

FIG. 4 is a diagram illustrating an embodiment in which the heads of the first half journaling and the second half journaling meet each other to determine a center point in the dual journaling storage method according to the present invention.

Referring to FIG. 4A, the first half head is denoted by H1, and the first half tail is denoted by T1. In addition, the head of the second half journaling was marked with H2 and tail as T2, and the center point was marked with C. When data Data1 enters such a file system in each partition, it is determined whether to journal in the first half or journal in the second half according to the data type, and stored in the head portion. In FIG. 4A, Data1 is data that is journaled from the first half, and therefore Data1 is stored from the first position with respect to the storage device.

FIG. 4B shows a state when six data are stored. Data1 through Data4 are data for the first half journaling, and Data5 and Data6 are data for the second half journaling.

In the next run, Data2 and Data6 were cleared. However, due to the nature of the journaling storage method, the data is not actually erased, but only marked as invalid.

In FIG. 4C, a garbage collection (GC) is generated due to insufficient storage space for the storage medium. That is, since Data1 is valid data, the data is moved to the head and the previous Data1 is invalidated, and when the size of the erase block is exceeded along with the previously invalidated Data2, the free space is secured by actually deleting the data. The actual deletion process is performed on each partition of flash memory, and when the disk is used, such deletion process is not necessary.

When free space is secured, the tail T1, which is the end of the first half journaling, is moved to the position of Data3. Similarly, when Data6 is invalidated and erased to the erase block size, the tail T2 of the second half of journaling is also moved. In this state, we want to store new data Data7. This data is intended to be stored in the first half head H1 as data of first half journaling, but there is insufficient space. Therefore, as shown in (d) of FIG. 4, only D7-1, which can be stored, is stored, and the first half head H1 returns to the beginning to store the remaining D7-2.

In this way, when the first half journaling encounters the second half journaling, it returns to the original position in a circular manner and saves it. In addition, the point where the head H1 of the first half and the head H2 of the second half met is set as the center point C. FIG. The latter head H2 also returns to the end position and waits for storage. In this way, data is stored in the first half journaling and the second half journaling, and the center point (C) is defined.                     

If you keep storing data in this way, one of the first half head H1 or the second half head H2 reaches the position of the center point C first, in which case the first journaling part has a lot of data to store. You can judge.

Therefore, the center point is moved to the other side to increase the space of journaling first arriving at the center point (C).

FIG. 5 illustrates an embodiment of a process of determining a new center point by determining a center point in the dual journaling storage method, and then increasing the head of the rear half journaling to meet the center point and moving the center point toward the front half journaling.

Referring to FIG. 5A, this shows a case where Data3 and Data5 are invalidated, data storage in the second half of the journaling is actively stored, Data8 and Data9 are stored, and data10 is about to be stored, but there is insufficient space.

In other words, in the second half, the center point C is first reached. Here, since the head H2 of the latter half does not meet the head H1 of the first half, the center point C is moved toward the first half as long as there is enough space to store in the first half.

Determination that there is enough data in the first half is made by performing GC of FIG.

To do this, as shown in FIG. 5 (b), the data of the first half portion D7-1 is moved to the first half head H1, and the center point C is also moved. At this time, the unit of data moving in the first half is the erase block unit in the case of flash memory.

Because you can move and erase to create a free space and then save new data.

Herein, the erase block refers to a memory unit that can be erased at one time in a flash memory, and is usually formed in a size of 128 Kbytes or 256 Kbytes. At this time, if the erase process is performed on the erase block, a free block, that is, a space for storing data is formed, and the free space means a free block having a predetermined size.

When such free space is created, new data Data10 is stored.

The movement of the center point C is moved until it meets the head H1 of the first half or until there is enough free data storage space in the first half.

6 is a flowchart illustrating an overall process of performing a dual journaling storage method according to the present invention.

That is, FIG. 6 is a flowchart illustrating a method of performing a dual journaling storage method according to the present invention described above with reference to FIGS. 4 and 5 by using a flow chart. Describes the process of moving a point.

4 to 6, the present invention illustrates a process of storing data, a process of determining a center point, and a process of moving a center point through a flowchart. The initial value of the head H1 in the first half of the storage device, the head H2 in the second half, the tail T1 of the first half, the tail T2 of the second half, and the center point C are basically zero (S101). This refers to the initial state in which the first half journaling data and the second half journaling data are stored in the file system.

 The data storage request for the file system is made through a buffer. In this state, when a storage request (S102) is made in a storage medium, that is, each partition, it is checked whether there is enough storage space through the GC of FIG. (S103) If the GC checks the space of each partition and the storage space of each partition is sufficient, the flow returns to the flowchart of FIG. 6 and continues. If not, the storage space is secured. Return directly to the flowchart to continue execution. Here, the positions of H1, H2 and the like are addresses that increase in the unit of byte in the flash memory, for example, and the data size S is the size of the byte unit, so the unit can be calculated in the same way.

In this state, it is checked whether the center point C is 0 (S104), which is to confirm whether the center point is first determined, which is different from the initial state before the center point C is determined and the processing after the determination. Because.

That is, when the center point C is first determined, it is necessary to confirm that the head meets the head of the other side, but when the center point is already formed, it is necessary to check whether the head meets the center point first.

When the center point C is 0 or non-O as a result of the determination of step 104, the present invention checks whether the data is the first half journaling data (S105), and stores the data accordingly.

First, it is assumed that the center point C is 0, and the newly stored data is the first half journaling data, that is, the first half of the storage device, and the size is S.                     

In this case, the head of the first half journaling data is located at H1 + S, and step 106 is performed to check whether the space for storing the S size data is available.

In other words, this is to confirm (S106) whether the head H1 + S of the stored first half journaling data meets the head H2 of the second half journaling data. If the first half journaling data head H1 + S to be stored does not meet the second half journaling data head H2, i.e., satisfies H1 + S < Since the storage space is sufficient, the first half journaling data is stored from the position of H1, so that the head of the data increases from the existing position of H1 to the position of H1 + S (S108). )

However, if H1 + S ≤ H2 is not satisfied in step 106, that is, if the stored front half journaling data head H1 + S meets the second half journaling data head H2, this means that the size of the data is determined by step 109. Only SH (H2-H1), the size of which can be stored, is stored from the position of H1.

In this case, the center point is also set to the position of H2, and the rest of the data (S- (H2-H1)) is stored again from the beginning of the first half journaling.

That is, as shown in step 109, the center point C value is no longer 0, H1 becomes 0, and the rest of the data (S- (H2-H1)) is stored from 0, and thus again. H1 is to increase by the size of (S- (H2-H1)). This is the content corresponding to (c) and (d) of FIG. That is, H1 in FIG. 2 (d) corresponds to (S- (H2-H1)), and becomes a new storage position.

If the stored data is the latter half journaling data, it is stored symmetrically with the above description (S107).

In addition, in step 104, even when the center point C is not 0, it is checked whether the stored data is the first half journaling data as in the case of 0 (S110).

However, if the center point C is not 0 in step 104, it means that the head of the first half journaling data and the head of the second half journaling data have already met and the center point has been determined. Therefore, when the stored data is the first half journaling data, H1 + S It is distinguished from the above description in that it must be checked that the center point exceeds the center point (C).

At this time, if the stored front half journaling data head H1 + S does not meet the center point C, i.e., satisfies H1 + S < The first half journaling data is stored from the position of, so that the head of the data increases from the existing H1 position to the position of H1 + S. (S112)

However, if in step 111 the H1 + S? S is not satisfied, i.e., the stored front half journaling data head H1 + S meets the center point C, it is determined by step 114 that the size of the data S ) Is stored from the position of H1 as much as (C-H1), which is a size that can be stored.

This is to ensure that the first half of the journaling data is large enough to secure the space, through which it is possible to evenly distribute the number of times of storage for the flash memory.                     

However, if the center point (C) is pushed toward the second half, the useful data of the second half journaling data is moved to H2. At this time, it is necessary to check whether there is a storage space available on the second half (S115). Check if there is space to store the part (S- (C-H1)) size. This is the content corresponding to Figure 5 (b).

If there is a storage space on the second half side, as in step 116, the data of the size (S- (C-H1)) is moved to the H2 position in the second half, and the new data S- (C-H1) is stored there. do. This can be understood through the transfer of D7-1 to H1 in FIG. 5 (b).

5 is a case in which the center point is pushed toward the first half and the opposite of the above description, but the principle is the same.

However, if there is no storage space on the latter half, this means that the latter half is full of data, pushing the midpoint to the second half as much as possible, as in step 118, and the rest comes to the zero position (i.e., H1 =). 0) Save and finish.

If the stored data is the latter half journaling data, it is stored symmetrically with the above description (S113).

When the above data storage process is completed, the GC process is called again as described with reference to FIG. 7. 7 is a flowchart illustrating a process of performing garbage collection (GC) as part of a dual journaling storage method.

In the process of performing GC of FIG. 7, once a request for data storage is received, GC is performed to check whether there is enough free space to store data.                     

The data to be stored once exists in the storage buffer. If there is no free space of the data size to be stored, the data is moved by the journaling method and the invalidation space is erased as much as the erased block. After the minimum space for new data is secured, the storage is performed first. This is the case where the first partial GC is called in Fig. 6 (S101-S103 in Fig. 6).

After checking whether there is data in the buffer (S202) in a state in which a free block exists for a certain data size (S201), and if there is data in the buffer, it is checked whether the data is the first half journaling (S203). do.

At this time, the free block is formed after the erase process is performed on the erase block, and means a space for storing data. In addition, free blocks of a certain size form a free space.

In step 203, if the data is not the first half journaling, the second half is also performed in the same manner as the first half (S204). On the contrary, if the data is the first half journaling, it is checked whether there is enough free space (S205).

In step 205, if the free space is sufficient, the GC ends. If the free space is not sufficient, the effective space is moved from the first half tail T1 to the first half head H1, and the invalidation space is secured and erased in the erase block (S206).

On the other hand, after the storage of the inserted data is performed, the GC is once again called to secure enough space in the storage space, that is, the storage space of each partition, in which case the number of erased blocks to be erased is determined by the graph of FIG. do. This is done when there is no data to store in the save buffer.

In this state, as shown in FIG. 8, if N ₂ or more free blocks are secured in the decision graph, the erase process for the erased block no longer occurs. N ₂ is usually set to about 10% of the total storage space. When the current number of free blocks is between N ₁ and N ₂ , the number of free blocks is deleted as much as the number of erased blocks to secure N ₂ or more free blocks. In this case, the N ₁ value means a limit value at which the free block is depleted, and may be set to 2 or 3 depending on the setting. That is, if only two or three free blocks remain in the current system, the system first moves valid data to another free block among the erased blocks containing invalid data and valid data, and thus the erased block becomes an invalidated block. Clearing process is performed to free up space.

In addition, the N ₂ value sets about 10% of the number of erase blocks of the entire flash memory.

Since the erase time of the flash memory block is very long, about 2 to 10 times the storage time and 100 to 1000 times the data reading time, the frequent erase process causes the system to slow down overall.

Thus, when it is considered that the space of the flash memory is considered to be considerable, the erase process is not performed without necessity, and it is generally about 10% that the free space of the flash memory is considered to be significant. If the number is less than N ₁ , the erased block is secured in advance of any operation. If the number of free erased blocks is less than or equal to N ₁ even after the delete operation is performed, there is no more storage space.

In addition, if the current number of free blocks is equal to or less than N ₂ in step 210, an invalidation space is secured in the erased block and erased accordingly (S210, 211).

The reason for not having enough free space from the first GC is that the erase process is more time consuming than read (read) or write (write). When the demand for data storage comes in, This is because the latency time for storage becomes long. In addition, since most flash memories perform a erase process and a read and write operation is required, the flash memory may suspend the erase process and perform a high priority operation.

In addition, the multi-division flash memory and the dual journaling storage method of data described with reference to FIGS. 3 to 8 may be used for various purposes.

Here, the number of partitions depends on the function of the flash memory. FIG. 8 illustrates a triple memory flash memory in one embodiment.

An example of using the triple split flash memory device is as follows. The first partition can be used to store data. The second partition can be used to store code executed by a device containing flash memory. The third partition can be used to allow code updates.

For example, if the update code changes, the original code stored in the second partition is executed while the new code is written to the third partition.

Once the new code is written and verified, the third partition is the partition used for the code. Thus, seamless update of the flash memory is possible.

In another embodiment of a triple segment flash memory device, code is executed from the first partition and data updates are made from the second partition. Therefore, when data update is required as a result of code execution, data update can be performed seamlessly.

9 illustrates an embodiment of a triple segment flash memory device according to the present invention.

Referring to FIG. 9, partition A 310, partition B 315, and partition C 320 are associated with an X decoder and a Y selector, respectively, and may be independently accessed.

The layout shown in FIG. 9 corresponds to one embodiment of the actual layout of the flash memory device.                     

X decoder 307 and Y selectors 309 and 312 are associated with partition A 305 and 310. In one embodiment, partition A 310 is divided in half by Y selectors 309 and 312. Partitioning of partition A 310 allows the first portion 310 of partition A to align with partition B, while the remaining portion 305 of partition A is partition ( partition) because of the purpose of the layout, such as to align with C.

At this time, in one embodiment, partitioning of partition A 310 may optimize read speed performance, and Y selectors 309 and 312 are connected to Y decoder 325.

Status register 335 is also associated with partition A. Status register 335 indicates the state of partition A--idle, being read, being written, or being erased. .

Similarly, for partition B, there is an X decoder 317, a Y selector 319, and a status register 340. Partition C also includes an X decoder 323, a Y selector 322, and a status register 345.

In one embodiment, a single user interface 330 is associated with status registers 335, 340, and 345 for each partition.

Sense amplifiers 350 support all partitions. In one embodiment, the number of sense amplifiers is eighteen.                     

Here, sixteen sense amplifiers 350 are used for a read operation on one of the partitions. One sense amplifier is used for parallel write operations from one of the partitions.

The interface includes a plurality of state machines that control each parallel write operation. Thus, if there are two parallel write operations (write to two partitions at the same time), there are two state machines.

In addition, the number of charge pumps 360 also corresponds to the number of parallel operations. In another embodiment, the number of connections for one charge pump 360 is equal to the number of parallel operations.

Each connection maintains a different voltage level, allowing multiple operations using different voltage levels. In one embodiment, independent wiring is connected with decoders associated with each partition.

Thus, the first connection connects to the first partition and the second connection connects to the second partition. The same is true for other connections. Thus, each connection outputs a variety of voltage levels corresponding to each operation that can be executed in the partition.

In another embodiment, the first connection outputs the voltage level required for writing, the second connection outputs the voltage level required for reading, and the third connection outputs the voltage level required for deletion. In this case, the switches connect the appropriate wiring to the appropriate partition, which is necessary for the operation to be performed.                     

10 shows an example of a portable terminal using the flash memory device according to the present invention.

The mobile terminal 410 includes a flash memory device 430 according to an embodiment of the present invention.

However, although the flash memory 430 is shown in the portable terminal 410, it should be understood that the flash memory 430 is generally accommodated in a receptacle in the main body of the portable terminal 410.

In addition, the portable terminal is provided with various buses and a processor connected to the bus, and the flash memory 430 according to the present invention is connected to the bus and accessible by the processor.

The illustrated mobile terminal 410 is running, executing code, and executing a partition 460 including currently activated code.

The use of such codes is known in the art. Another partition 450 contains call or voice data. For example, the mobile terminal 410 may include a calling director or similar data in the data partition 450.

The third partition 470 accepts the new code 440 from the outside. In one embodiment, the third partition can be updated remotely. Thus, while the mobile terminal is in operation, a new code 440 is written to a new code partition 470 and a data partition 450 is used to reproduce the calling data, while at the same time a partition. Code stored at 460 may be executed.

In this manner, the portable terminal allows for the update of seamless mobile phone codes, simultaneous updates and the use of the portable terminal. Other application areas, such as seamless code updates, can be implemented similarly.

In addition, the data storage in each partition is characterized by the dual journaling storage method according to the present invention described with reference to FIGS.

As described above, in the embodiment of the present invention, a plurality of partitions are included in the flash memory device to allow a read operation during writing, and each partition can be read, written, and deleted along with other partitions. In addition, for the data stored in each partition of the flash memory to separate the metadata and the normal file data, the file data is stored from the storage medium, that is, from the beginning of each partition, the metadata from the end of each partition It describes a dual journaling storage method for storing in the first direction.

When using the dual journaling storage method as in the embodiment, it is possible to achieve fast data access time because the same type of data is kept in a certain area, and the number of erases from the flash memory can be evenly distributed in the flash memory space.

In addition, according to the characteristics of the journaling storage method, if a data error occurs due to a power failure, data recovery to the previous version is easy, thereby ensuring the reliability of the data.

What has been described above is only one embodiment that describes a dual journaling storage method for storing data in a storage medium according to the present invention, and the present invention is not limited to the above-described embodiment, and is claimed in the following claims. Without departing from the gist of the present invention, any person having ordinary knowledge in the field of the present invention will have the technical idea of the present invention to the extent that various modifications can be made.

Claims (22)

In a flash memory device, Multiple partitioned memory, A plurality of partitions separated by multiple divisions of the memory, in which data to be stored can be independently written, read or deleted; A charge pump providing a plurality of voltage outputs for outputting voltages for writing, reading and erasing; A plurality of first sense amplifiers comprising a plurality of first sense amplifiers for read operations in which each partition is executable at the same time and at least one sense amplifier for erase and write operations in which each partition is executable simultaneously; The data stored in each partition is stored toward the center from each of the first and last positions of the storage space of each partition, and is stored from the head of the first half journaling stored at the first position of the storage space and the end position of the storage space. And after the head of the second half journaling meets the center point for the first time, and when the first half or the second half journaling head meets the center point again, the center point is moved toward the opposite journaling. Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, When the type or the nature of the data stored in each partition is different, the multi-partitioned flash memory device, characterized in that divided into the first half journaling and the second half journaling. Claim 3 was abandoned when the setup registration fee was paid. 3. The method of claim 2, And when data stored separately divided into the first half journaling and the second half journaling are met at a center point, the data is stored again at an initial position. Claim 4 was abandoned when the registration fee was paid. 3. The method of claim 2, After the head of the first half journaling and the head of the second half journaling meet and the center point is formed for the first time, for the case where the center point is formed a second time or more, when the first half or the second half head meets the center point again, the center point is the opposite journaling. Move toward to the head, wherein the head indicates a location for storing data. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 1, The data stored in each partition is divided into metadata and general file data, the file data is stored from the beginning of each partition, and the metadata is stored in the first direction from the end of each partition. Based on at least one of the amount of one data stored at the start position and the end position of the storage space and the amount of each available storage space, the position of the center point is configured to move in the direction of storing more data And a multiple partitioned flash memory device. Bus, A processor connected to the bus, A flash memory connected to the bus, accessible by the processor, and divided into a plurality of partitions, in which data stored in each partition can be independently written, read or deleted; A plurality of first sense amplifiers comprising a plurality of first sense amplifiers for read operations in which each partition is executable at the same time and at least one sense amplifier for erase and write operations in which each partition is executable simultaneously; The data stored in each partition is stored toward the center from the start position and the end position of the storage space of each partition. When the type or the nature of the data stored in each partition is different, the first half journaling and the second half journaling are respectively used. When the head of the first half journaling and the head of the second half journaling meet each other and the center point is first formed, and the center point is formed second or more, when the first half or the second half head meets the center point again, And the center point is moved to the opposite journaling side. delete Claim 8 was abandoned when the registration fee was paid. The method of claim 6, And when data stored separately divided into the first half journaling and the second half journaling are met at a central point, the data is stored at the first position again. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 6, After the head of the first half journaling and the head of the second half journaling meet and the center point is formed for the first time, for the case where the center point is formed a second time or more, when the first half or the second half head meets the center point again, the center point is the opposite journaling. And a head indicates a location for storing data, wherein the head is a multi-divided flash memory device. Claim 10 was abandoned upon payment of a setup registration fee. The method of claim 6, The data stored in each partition is divided into metadata and general file data, the file data is stored from the beginning of each partition, and the metadata is stored in the first direction from the end of each partition. Based on at least one of the amount of one data stored at the start position and the end position of the storage space and the amount of each available storage space, the position of the center point is configured to move in the direction of storing more data A portable terminal employing a multi-divided flash memory device, characterized in that. In the method for storing data in each partition of the flash memory divided into a plurality of partitions, each data can be written, read or deleted for each partition, In storing data from the first position and the end position of the storage space of each partition toward the center, when data of different types or characteristics are stored in the storage medium, the data is divided into first half journaling and second half journaling. When the head of the first half journaling and the head of the second half journaling meet and the center point is formed first, and then, when the first half or the second half head meets the center point for the case where the center point is formed more than a second time, the center point is directed toward the opposite journaling. The method of claim 2, wherein the head represents a location for storing data. delete Claim 13 was abandoned upon payment of a registration fee. The method of claim 11, And storing the data in the divided memory, wherein the data is stored so that the first half journaling and the second half journaling are met at the center point. delete Claim 15 was abandoned upon payment of a registration fee. The method of claim 11, The data stored in each partition is divided into metadata and general file data, the file data is stored from the beginning of each partition, and the metadata is stored in the first direction from the end of each partition. Based on at least one of the amount of one data stored at the start position and the end position of the storage space and the amount of each available storage space, the position of the center point is configured to move in the direction of storing more data Dual journaling storage method for storing data in the divided memory, characterized in that. In the journaling storage method when inserting data into each partition of the flash memory which is divided into a plurality of partitions and data can be recorded, read or deleted for each partition, Performing a GC (Garbage collection) when a request for data insertion is input to each partition, and moving and erasing data when there is not enough storage space; And Checking whether there is enough space in each partition after data storage is completed to secure a space for storing the next inserted data; and if the type or nature of data stored in each partition is different, first half journaling And the second half journaling and the second half journaling, respectively, are stored in the front half journaling head and the second half journaling head, and the center point is formed for the first time after the center point is formed. Is again encountered, the center point is moved toward the opposite journaling, based on at least one of the amount of data stored in the first position and the end position of the storage space and the amount of available storage space, The location of the point to store more data A dual journaling storing method for storing data in the divided memory, characterized in that formed for movement. Claim 17 has been abandoned due to the setting registration fee. The multi-partitioned flash memory device of claim 4, wherein the center point is variably formed based on an amount of data to be stored or a size of each storage area in which data is stored. Claim 18 was abandoned upon payment of a set-up fee. 18. The method of claim 1 or 17, wherein each region of the first half journaling and the second half journaling in the partition area of the multi-partitioned memory is variably formed based on the amount of data to be stored or the size of each storage area in which data is stored. Multi-partitioned flash memory device. Claim 19 was abandoned upon payment of a registration fee. 12. The method of claim 11, wherein in storing data from the start position and the end position of the storage space of each partition toward the center, the center point is variable based on the amount of data to be stored or the size of each storage area in which the data is stored. Dual journaling storage method for storing data in the divided memory, characterized in that formed as. 12. The data to be stored according to claim 11, wherein when data stored from either the first position or the end position of the storage medium meet with each other at any position of the storage medium storage center point, the data to be stored is the head or end position of the initial position. A dual journaling storage method for storing data in a partitioned memory, characterized in that the data is stored again in at least one portion of the head. 17. The method of claim 16, wherein when the GC and erase operations occur, the tail is moved to a central portion of the memory of the first half or second half journaling. 17. The dual journaling storage of claim 16, wherein, when the GC and erase operations occur, valid data is moved to the location of the head of the first half or second half journaling. Way.

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