CN115757212A - GB level single write read memory - Google Patents

Abstract

The invention discloses a GB-level single-write-read memory, which uses standard NAND flash memory as a storage medium, and standard NAND ONFi as an external interface; on the external interface, it becomes a NAND memory that can only be written once and read once, and each data page It has the function of only writing once and reading only once; reading and writing is based on the data page, even if only a part of the page is read and the rest is given up, the page is considered to be read once, and this page Content cleared. The invention uses NAND flash memory as a storage medium, and uses an additional controller with a page read-write permission table to realize a memory with a GB capacity level that only allows one-time writing and one-time reading, and has high control efficiency.

Description

GB level single write read memory

technical field

The invention relates to a storage component of a computer system, in particular to a GB-level single write-read memory.

Background technique

Memory is the necessary foundation of various digital devices, and common access methods can be divided into two types:

1. It can be written multiple times and read multiple times (RAM, such as DRAM, SRAM, etc.);

2. Once written, can be read multiple times (ROM, such as PROM, EPROM, etc.);

When the limited memory can only read valid content once after one write, this access method is called single write-single read storage (Write_Once, Read_Once), write once, and destroy the written content after reading , can only be read correctly once. This storage method can be used for program access interlocking (the unit length of memory read and write is generally 32-bit full word length, refer to https://www.open-std.org/jtc1/sc22/wg21/docs/papers/ 2015/n4444.html, Linux-Kernel Memory Model), system security, data information security (the length of the storage read-write unit is long, and the one-time write-read memory related to data security can reach more than MB bytes, reference information 1: Method for read oncememory, US7107388B2, https://patents.google.com/patent/US7107388B2/en, reference information 2: Read-once memory, publication number: US1049567B2, content provided by Intellectual Property Publishing House, https://wenku.baidu. com/view/29d6fcb7f624ccbff121dd36a32d7375a417c6b1.html), etc.

Write Once Read Once memory (Write Once Read Once) has a special purpose in system security and data security protection. Usually a read (READ ONCE MEMORY) is implemented by a volatile memory (SRAM, DRAM, etc.) or a special storage medium. The storage capacity of the former is a full word length (calculated as a 32-bit word length), while the latter is expensive and difficult to reach the GB level. capacity. The storage controller of the present invention uses NAND flash memory as a storage medium, and uses an additional controller with a page read and write permission table to realize a memory that only allows writing once and reading once at the GB capacity level.

Contents of the invention

Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a GB-level single-write-read memory, the storage controller uses NAND flash memory as the storage medium, and an additional controller with a page read-write permission table realizes the GB capacity level Only allow one write, one read memory, high control efficiency.

In order to achieve the above object, the present invention is realized through the following technical solutions: GB-level single write-read memory, using standard NAND flash memory as the storage medium, and standard NAND ONFi as the external interface. On the external interface, it becomes a NAND memory that can only be written once and read once (WRITE ONCE READ ONCE). Each data page has the function of writing only once and reading once. The unit of reading and writing is a data page. Even if only a part of the page is read and the rest of the page is abandoned, the page is considered to have been read once, and the content of this page is cleared.

Described standard storage medium is distributed into data block, write interlock module (write lock blocks) and read interlock module (read lock blocks) three parts; Write one byte of interlock module to control one data block For the write operation of a page, read a byte of the interlock module to control the read operation of a data module; select a page with a length of 512 bytes, and the space occupied by the write interlock module and the read interlock module is the data module A tiny fraction of the space (1/256).

The format of the write lock module control byte is,

b0:0 means initialized, 1 original state;

bit 1~2: mode: 00-reusable write once read 01-write once read, 10, 11-reserved;

bit 3:0-one write lock status (locked), 1-permit write (Permit write);

Bit 4～7: reserved for additional extended control (aux control), including the number of repeated reading and writing.

The format of the read-out locking module control byte is:

b0:0-data is valid, 1-invalid data;

bit 1～2: Mode: 00-write once and read multiple times 01-write once and read once, 10, 11-reserved;

bit 3:0-read the lock status (locked) once, 1-permit read (Permit read);

Bit 4~7: reserved for extension.

When a write-read memory is used for the first time, the write lock control block and the read lock control block are initialized, and all write lock control bytes are set to 1111-1010 states;

(When allowing repeated use that has been deleted by one read, it is set to the 1111-1000 state), allowing writing; all read lock control bytes are set to the 1111-1011 state, and the data is invalid. The initialized lock control block is written into the control area of the NAND flash memory.

In normal use, after receiving a reset signal, the controller puts the read-write lock control block in the flash memory into the controller to control access to the external interface. The read-write control table (write permit map readpermit map) placed in the controller is the mirror image of (write lock block and read lock block) in the flash memory, and is placed in the controller to improve efficiency.

When the external interface writes a data page, the controller checks the third bit of the corresponding write control word in the write control table. If it is 1, it will write to the flash memory according to the external interface command, and if it is 0, the write operation will be ignored. When writing, the control word in its flash memory is also updated;

When the external interface reads a data page, when the controller checks that the zeroth bit of the corresponding control word in the read control table is 0 (data valid bit) and the third bit is 1 (reading allowed), the read operation of the external interface is completed . Then if the mode of the read control bit is a read (first and second bits 01), then the page is all set to 0, so as to achieve the purpose of destroying the original content and realize the only correct data reading that cannot be recovered on the medium. At the same time, write the read-out control word of the controller into the flash memory, and update the read-out control word.

Beneficial effects of the present invention: the memory structure of the present invention is reasonably designed, the storage controller uses NAND flash memory as the storage medium, and the additional controller with the page reading and writing permission table realizes that the GB capacity level only allows one-time writing and one-time reading memory, which improves the control efficiency.

Description of drawings

The present invention is described in detail below in conjunction with accompanying drawing and specific embodiment;

Fig. 1 is a controller schematic diagram of the present invention;

Fig. 2 is the work flow diagram of only writing once and reading once of controller of the present invention;

Fig. 3 is a specific implementation flowchart of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

Referring to Figures 1-3, this embodiment adopts the following technical solutions: GB-level single-write-read memory, using standard NAND flash memory as the storage medium, and standard NAND ONFi as the external interface. On the external interface, it becomes a NAND memory that can only be written once and read once (WRITE ONCE READ ONCE). Each data page has the function of writing only once and reading once. The unit of reading and writing is a data page. Even if only a part of the page is read and the rest of the page is abandoned, the page is considered to have been read once, and the content of this page is cleared.

Described standard storage medium is distributed into data block, write interlock module (write lock blocks) and read interlock module (read lock blocks) three parts; Write one byte of interlock module to control one data block For the write operation of a page, read a byte of the interlock module to control the read operation of a data module; select a page with a length of 512 bytes, and the space occupied by the write interlock module and the read interlock module is the data module A tiny fraction of the space (1/256).

The schematic diagram of the controller of this specific embodiment is shown in FIG. 1 , in which 101 and 102 are mirror images of the read-write latch control block stored in the flash memory, so as to improve control efficiency. In the figure, the MCU is used to initialize and update the control block. The internal and external interfaces of the controller are all standard flash memory interfaces, and the internal interface is connected to the standard flash memory. What the host sees on the external interface is a GB-level capacity flash memory that implements the Read Once standard.

The work flow of the write-once-read-once controller of this specific embodiment is shown in Figure 2, in which 201 is the initialization operation of the control block, 202 is the update operation of the write control block, and 203 is the update operation of the read control block. The specific implementation process is shown in Figure 3, 301 process selection control in the figure (reusable single write read and one-time single write read memory), 302 is the update of the write control block and the read control block when reused recover.

Embodiment 1: The control flow of GB-level single write-read memory is as follows:

After adding a point and starting up, if the write permission table (WRITE PERMIT MAP) and the read permission table (READ PERMIT MAP) are all allowed (all are one), then the controller enters the initialization stage.

Normal write and read phase (the only time to write, the only time to read).

Recycling stage. After a simple read-once memory is effectively written and read once, there is no other valid content except that the page has been used, and its storage capacity is in an abolished state. This controller implementation can adopt the reuse option, that is, after the valid content has been effectively read once and destroyed, it is reused for the next single write and read (Write Once, Read Once). Indicate that the page has been reused at least once in the reserved digits of the control subsection. This improves the utilization of the flash memory.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. GB-level single write-read memory, characterized in that standard NAND flash memory is used as storage medium, and standard NAND ONFi is used as external interface; on the external interface, it becomes a NAND memory that can only be written once and read once, and each data page has The function of writing only once and reading only once; read and write is based on the data page, even if only a part of the page is read and the rest is given up, the page is regarded as read once, and the content of this page is read clear. 2. The GB-level single-write-read memory according to claim 1, wherein the standard storage medium is divided into three parts: a data block, a write-in interlock module, and a read-out interlock module; One byte of the lock module controls the write operation of one page of a data block, and one byte of the read interlock module controls the read operation of one data module; select a page with a length of 512 bytes and write it into the interlock module The space occupied by the readout interlock module is 1/256 of the data module space. 3. GB level single write-read memory according to claim 2, is characterized in that, the format of described write lock module control byte is: b0:0 means initialized, 1 original state; bit 1~2: mode: 00-reusable write once read 01-write once read, 10, 11-reserved; bit 3: 0-one-time write lock status, 1-allow writing; Bit 4~7: Reserve additional expansion control, including the number of repeated reading and writing. 4. GB level single write-read memory according to claim 2, is characterized in that, the format of described read-out locking module control byte is: b0:0-data is valid, 1-invalid data; bit 1～2: Mode: 00-write once and read multiple times 01-write once and read once, 10, 11-reserved; bit 3: 0-read the lock status once, 1-allow reading; Bit 4~7: reserved for extension. 5. GB-level single write-read memory according to claim 1, is characterized in that, when once write-read memory is used for the first time, the initialization of write lock control block and read lock control block is carried out, and all write lock control bytes are reset. 1111-1010 status; When the data that has been deleted by a read is allowed to be reused, it is set to the state of 1111-1000, and writing is allowed; all read lock control bytes are set to the state of 1111-1011, and the data is invalid; the initialized lock control block is written to the control area of the NAND flash memory . 6. The GB-level single-write-read memory according to claim 1 is characterized in that, during normal use, after receiving the reset signal, the controller puts the read-write lock control block in the flash memory into the controller, and externally The access of the interface is controlled; the read-write control table placed in the controller is a mirror image in the flash memory, which is placed in the controller to improve efficiency; When the external interface writes a data page, the controller checks the third bit of the corresponding write control word in the write control table. If it is 1, it will write to the flash memory according to the external interface command, and if it is 0, the write operation will be ignored; when writing , the control word in its flash memory is also updated; When the external interface reads a data page, when the controller checks that the zeroth bit of the corresponding control word in the read control table is 0 and the third bit is 1, the read operation of the external interface is completed; then if the mode of the read control bit is Once read, all the pages are set to 0 to achieve the purpose of destroying the original content and realize the only correct data read that cannot be recovered on the medium; at the same time, write the read control word of the controller into the flash memory to update its read control word.

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