WO2020082449A1

WO2020082449A1 - Method for mapping table corresponding to logical position of management host in flash memory storage

Info

Publication number: WO2020082449A1
Application number: PCT/CN2018/115510
Authority: WO
Inventors: 黄中柱; 李庭育; 魏智汎; 张盛豪
Original assignee: 江苏华存电子科技有限公司
Priority date: 2018-10-24
Filing date: 2018-11-14
Publication date: 2020-04-30
Also published as: CN109375877A

Abstract

A method for a mapping table corresponding to the logical position of a management host in a flash memory storage, comprising the following steps: A, confirming a segment corresponding to data of a management host in a flash memory storage; B, adding 1 to the hit rate of the confirmed segment; C, confirming whether the segment is present in a memory; D, confirming whether to write the segment back into the flash memory; E, according to the hit rate, determining a segment to be written back into the flash memory. The described method proposes to store two segments in a memory, determine according to the amplitude of the related hit rates of the segments which segment to write back into a flash memory, and read from the flash memory a segment corresponding to data of a host and place the segment in the memory when determined that the segment is present in the memory, or determine a segment that is written back into the flash memory according to the hit rate, read from the flash memory a segment corresponding to data of a host and place the segment in the memory when determined that the segment is not present in the memory, thereby greatly improving the efficiency of execution.

Description

Method for managing mapping table corresponding to logical position of host end in flash memory storage

Technical field

The invention relates to the technical field of managing the mapping table corresponding to the logical position of the host end in the flash memory storage, in particular to a method for managing the mapping table corresponding to the logical position of the host end in the flash memory storage.

Background technique

Flash memory (Flash) is a long-life non-volatile memory (which can retain the stored data information in the event of a power failure). Data deletion is not in a single byte but in fixed blocks As a unit (note: NOR Flash is byte storage.), The block size is generally 256KB to 20MB. Flash memory is a variant of electronically erasable read-only memory (EEPROM). The difference between flash memory and EEPROM is that EEPROM can be deleted and rewritten at the byte level instead of the entire chip erase, and most of the chips of flash memory require block erase except. Because it can still save data when the power is off, flash memory is usually used to save setting information, such as saving information in the computer's BIOS (basic program), PDA (personal digital assistant), digital camera, etc.

There are n blocks in one flash memory, and there are n pages in one block. After a page is written with data, it cannot be written to this page again unless the block containing this page is erased. The flash memory has the characteristic that the same location cannot be written repeatedly. Because the flash memory has this feature, the flash memory storage device needs to have a function of logical position corresponding to the physical position. With the current technology, the corresponding position is managed through a mapping table of the logical position corresponding to the physical position. This table will be placed in the memory of the flash storage device to operate.

As the capacity of the flash memory storage device becomes larger and larger, the memory capacity required to record the entire logical position corresponding to the physical location mapping table is greater, and the current technology will cut the table into n segments according to the memory size, such as memory available The space is 1024 bytes. If the size of the mapping table that records the entire flash storage device is 8192 bytes, the entire mapping table is divided into 8 segments, which are a to h.

NOR type and NAND type flash memory are very different. For example, NOR type flash memory is more like a single-chip flash memory, with separate address lines and data lines, but the price is more expensive and the capacity is relatively small; while NAND type is more like a hard disk, The address line and the data line are shared I / O lines. All information similar to the hard disk is transmitted through a single hard disk line, and compared with the NOR type flash memory, the NAND type has a lower cost and a much larger capacity. Therefore, NOR flash memory is more suitable for frequent random reads and writes. It is usually used to store program code and run directly in flash memory. Mobile phones are large users of NOR flash memory, so the "memory" capacity of mobile phones is usually not large; It is mainly used to store data. Our commonly used flash memory products, such as flash disks and digital memory cards, use NAND flash memory. Here we also need to correct a concept, that is, the speed of flash memory is actually very limited, its operation speed and frequency are much lower than that of memory, and the operation method of NAND flash memory similar to hard disk is also much slower than the direct access method of memory . Therefore, don't think that the performance bottleneck of the flash disk is in the interface, and even assume that the flash disk will get a huge performance improvement after using the USB2.0 interface.

As mentioned earlier, the operation method of NAND flash memory is inefficient. This is related to its architectural design and interface design. It really operates like a hard disk (in fact, NAND flash memory did consider the compatibility with the hard disk at the beginning of the design), it The performance characteristics are also very similar to hard disks: the operation speed of small data blocks is very slow, while the speed of large data blocks is very fast, this difference is much larger than other storage media. This performance feature is very worthy of our attention.

Flash memory access is relatively fast, no noise, and small heat dissipation. The demand for user space capacity is small. If you plan to purchase, you can not consider too much, and buy flash memory for the same storage space. If you need a large capacity (such as 500G), buy a hard disk, which is cheaper and can meet the needs of user applications.

Only the segment related to the host data is stored in the memory, and the other segments are stored in the flash memory. When the segment in the memory is not related to the current host data, the updated content of the segment needs to be stored in the flash memory, and the relevant segment is taken out from the flash memory and put into the memory.

If the segment order related to the host data is: segment a-> segment c-> segment a-> segment d has been repeatedly looped, so the operation process will become segment a written to flash memory, from Read segment c from flash memory, then write segment c to flash memory, read segment a from flash memory, then write segment a to flash memory, then read segment d to memory, and repeat This will increase the number of flash memory reads and writes and reduce the execution efficiency of the storage device.

Summary of the invention

An object of the present invention is to provide a method for accelerating the execution speed of a storage device and reducing the number of writes and reads of a flash memory, thereby improving the execution efficiency. Problems raised in technology.

In order to achieve the above object, the present invention provides the following technical solution: A method for managing a mapping table corresponding to a logical position on a host side in a flash memory storage includes the following steps:

A. Confirm the segment corresponding to the management host data in the flash storage;

B. The hit rate of the confirmed segment is +1;

C. Confirm whether this segment exists in the memory;

D. Confirm whether to write the memory segment back to the flash memory;

E. Determine the segment to write back to the flash memory according to the hit rate.

Preferably, the flash memory in step A is provided with a single chip microcomputer, a flash memory controller, an input and output control module, a storage unit array and a pre-charging unit.

Preferably, the management host in the flash storage in step A includes a CPU module, a reading unit, an execution controller, an input and output controller, a cache, a data converter, and a mapping table.

Preferably, the memory storage in the step C includes a mapping table. The mapping table includes 2 segments and a hit rate mechanism. The segment and the hit rate mechanism are provided with a calculator and an identification module, and each segment includes 1024 byte.

Preferably, the capacity of the mapping table pair is 8192 bytes.

Compared with the prior art, the beneficial effects of the present invention are:

In order to improve the use efficiency of the physical location mapping table corresponding to the logical position in the storage device, accelerate the execution speed of the storage device, and reduce the number of write and read times of the flash memory, it is proposed to place multiple segmented contents in the memory and hit The rate mechanism determines the method of replacing segments, reads the segment corresponding to the host data from the flash memory and puts it into the memory, which greatly improves the execution efficiency.

BRIEF DESCRIPTION

1 is a schematic diagram of the segmentation sequence related to host data of the present invention;

2 is a schematic diagram of storing two segments in the memory of the present invention;

FIG. 3 is a flowchart of a method for determining replacement segments by adding multiple segment contents in the memory of the present invention and a hit rate mechanism.

detailed description

The technical solutions in the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

Please refer to FIG. 1, FIG. 2 or FIG. 3, the present invention provides a technical solution: a method for managing the mapping table corresponding to the logical position of the host side in the flash storage: including the following steps:

B. The hit rate of the confirmed segment is +1;

C. Confirm whether this segment exists in the memory;

D. Confirm whether to write the memory segment back to the flash memory;

Confirm that the segment corresponding to the management host data in the flash storage is provided on the flash storage, including a microcontroller, flash controller, input and output control module, storage unit array and pre-charging unit. Fetch unit, execution controller, input and output controller, cache, data converter, mapping table.

The hit rate of the confirmed segment is +1, and it is confirmed whether the segment exists in the memory. The memory storage includes a mapping table. The capacity of the mapping table pair is 8192 bytes. The mapping table includes 2 segments and the hit rate mechanism. , Segment and hit rate mechanism are equipped with calculator and recognition module, each segment includes 1024 bytes.

Only the segment related to the host data is stored in the memory, and the other segments are stored in the flash memory. When the segment in the memory is not related to the current host data, the updated content of the segment needs to be stored in the flash memory, and the relevant segment Remove from flash memory and put in memory.

When the segment order related to the host data is: segment a-> segment c-> segment a-> segment d has been repeatedly looped, so the operation process will become segment a written to flash memory, from Read segment c from flash memory, then write segment c to flash memory, read segment a from flash memory, then write segment a to flash memory, then read segment d to memory, and repeat This will increase the number of flash memory reads and writes, which will greatly reduce the execution efficiency of the storage device.

Confirm whether you want to write the memory segment back to the flash memory, and determine the segment to be written back to the flash memory according to the hit rate. If it is segment a-> segment c-> segment a-> segment d, the situation has been repeated repeatedly. First store segment a in memory, then store segment c, because segment a does not need to be taken out of flash memory in memory, then segment c is written back to flash according to the hit rate, and then segment d is read out In memory.

The method of managing the mapping table corresponding to the logical position of the host side first confirms the segment corresponding to the host data, and then obtains the hit rate of this segment +1. After calculation, it is judged whether the corresponding segment exists in the memory. The corresponding segment, then read the segment corresponding to the host data from the flash memory and put it into the memory, if there is no corresponding segment in the memory, then it will judge whether to write the memory segment back to the flash memory, the memory Corresponding segments that do not exist in the system, determine the segments that are written back to the flash memory based on the hit rate, and finally read the segments corresponding to the host data from the flash memory and put them in memory to output the results.

In order to improve the use efficiency of the mapping table corresponding to the physical position of the logical position in the storage device, the invention speeds up the execution speed of the storage device, and reduces the number of writing and reading of the flash memory, placing multiple segmented contents in the memory plus the hit rate mechanism To determine the method of replacing the segments, read the segments corresponding to the host data from the flash memory and put them into the memory to greatly improve the execution efficiency.

The beneficial effects of the present invention are:

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention And variations, the scope of the invention is defined by the appended claims and their equivalents.

Claims

A method for managing the mapping table corresponding to the logical position of the host side in the flash memory storage includes the following steps:

A. Confirm the segment corresponding to the management host data in the flash storage;

B. The hit rate of the confirmed segment is +1;

C. Confirm whether this segment exists in the memory;

D. Confirm whether to write the memory segment back to the flash memory;

E. Determine the segment to write back to the flash memory according to the hit rate.
The method for managing the mapping table corresponding to the logical position of the host side in the flash memory storage according to claim 1, characterized in that: in the step A, the flash memory storage is provided with a single chip microcomputer, a flash memory controller, an input and output control module, and a storage unit Array and pre-charge unit.
The method for managing the mapping table corresponding to the logical position of the host side in the flash memory storage according to claim 1, wherein the step A: the management host in the flash memory storage includes a CPU module, a reading unit, an execution controller, and an input Output controller, cache, data converter, mapping table.
A method for managing a mapping table corresponding to a logical location on a host side in a flash memory storage according to claim 1, wherein the memory storage in the step C includes a mapping table, and the mapping table includes 2 segments and a hit ratio mechanism , Segment and hit rate mechanism are equipped with calculator and recognition module, each segment includes 1024 bytes.
A method for managing a mapping table corresponding to a logical position on a host side in a flash memory storage according to claim 3, wherein the capacity of the mapping table pair is 8192 bytes.