WO2007104649A1

WO2007104649A1 - Method of operating and managing unrestricted memory in a rewritable non-volatile memory, and associated memory

Info

Publication number: WO2007104649A1
Application number: PCT/EP2007/051911
Authority: WO
Inventors: Pierre Girard; Frédéric Faure; Pascal Di Girolamo
Original assignee: Gemplus
Priority date: 2006-03-13
Filing date: 2007-02-28
Publication date: 2007-09-20
Also published as: FR2898421A1

Abstract

The present invention relates to the field of rewritable non-volatile memories. The invention relates more particularly to a rewritable non-volatile memory device comprising a plurality of erasable data sectors and a method of managing such a memory. The method comprises: an initialization step consisting in recording data of a first type in at least one part of the unrestricted sectors of the memory and in assigning a state E<SUB>PUB</SUB> to each of said sectors used; and a subsequent step of writing data of a second type into the memory consisting, if the unrestricted sectors of the memory exhibit a smaller space than a threshold value, in recording said data of the second type on a part of said sectors that are associated with a state E<SUB>PUB</SUB>, and in modifying the state of these sectors.

Description

METHOD FOR OPERATING AND MANAGING FREE MEMORY IN RE-ENCRYPTIBLE NON-VOLATILE MEMORY,

AND ASSOCIATED MEMORY

The present invention relates to the field of non-volatile rewritable memories, such as EPROM memories (reprogrammable read-only memory), EEPROM (electrically erasable and programmable read-only memory) or flash.

More particularly, it relates to a method of managing such a rewritable non-volatile memory storing data of several types to best exploit the memory space l ibre.

Flash memory management methods are known for recovering memory space. The flash memories are organized into erasable memory blocks, themselves structured in memory sectors. Only memory blocks can be reset or cleared. The memory sectors are either free or unused if no data has been recorded, or used when the data stored in the sector are used, or expired when the data recorded in the sector are no longer used and more accessible by programs. computer.

The method described in US Pat. No. 6,621,746 proposes a management of the flash memory in which memory blocks are reset or erased when the number of expired memory sectors is greater than the number of free memory sectors or when these expired memory sectors have a space. memory less than that required for writing data. Similarly, the method described by US Pat. No. 5,337,275 is based on the listing of expired sectors, the evaluation of the number of free sectors and then the transmission of warning signals to a host equipment when this number of free sectors falls under certain conditions. critical thresholds. In response to these signals, the host equipment controls the reset of blocks including expired sectors listed.

These solutions focus on the recovery of out-of-date sectors according to relatively common criteria, in this case when these out-of-date sectors represent an important memory space.

It is understood that the expired sectors have a special status since they correspond to data which ceases to be exploited, that is to say that they can be erased without any control since they are useless. These methods of the prior art do not provide solutions for the management of data operated in two modes.

An object of the present invention is therefore to provide efficient management of the memory in which data exploited in several modes are recorded.

However, PCT patent application WO 02/084610 discloses a method for managing data stored in a rewritable non-volatile memory and intended to be managed according to two modes. The storage and exploitation of this data is based on an identification provided for each of them. The exploitation of the data is based on the assumption that some of the data, called administrative data, have a useful life. Thus when the end of utility of these data is detected, the system can authorize their erasure. It should be noted that this solution is similar to the two solutions mentioned above in that the data at the end of utility are comparable to outdated data. Thus, this solution is not appropriate for managing and exploiting data that does not necessarily have a useful life.

Another object of the present invention is therefore to enable the management of non-volatile rewritable memories for the exploitation of data of various types that do not necessarily have an end of utility.

Another object of the present invention is to make this management dynamic, automatic, and transparent to the user.

Moreover, a non-negligible space of these memories generally remains untapped at a given moment. For commercial applications, for example, it may be appropriate to exploit this space as long as it is not required for user data.

Another object of the present invention is then to provide a solution for optimizing the use of the memory by making it possible to store data of a first type, for example advertising, without altering the operation, for the user, memory as to the recording and exploitation of user data, and to release this advertising data when the memory space is required.

The invention aims to meet at least one of these aims and to solve the disadvantages of the prior art. In particular, the invention makes it possible to use the free space of the memories by recording therein non-personal data, data of advertising (eg, preloaded web pages, advertising, game-type applications, information or announcements, film or music excerpts, etc.) and to ensure the management of this data, which can continue in the future. time, as the so-called personal data, that is to say generated by the user during the operation of the computer system, are manipulated (written, read, erased, ...) in this memory. In such a configuration, the invention makes it possible to dynamically manage these advertising data in a manner that is transparent to the user and to avoid any conflict with the computer system for the manipulation of personal data and advertising data.

An application of the present invention is to maximize the use of all memory sectors free memory of a portable personal device such as a USB key (universal serial bus), a SIM card (identification module of the subscriber) or a mobile phone card MMC (multimedia card) for the dissemination of advertising data to users while allowing the conventional use of these memories. These can be filled with advertising data until there remains only a negligible portion of free sectors (for example the free memory space is less than a threshold value).

For this purpose, the invention firstly relates to a method for managing a rewritable non-volatile memory comprising a plurality of erasable data sectors, the method comprising:

an initialization step of storing data of a first type in at least a portion of the free sectors of the memory and assigning an E _PUB state to each of said used sectors, and

a subsequent step of writing data of a second type into the memory consisting, if the free sectors of the memory have a space less than a threshold value, to record said data of the second type on a part of said sectors associated with an E _PUB state, and to modify the state of these sectors.

Non-user generated advertising data is stored in the free memory sectors in order to take advantage of them rather than not exploiting them. In order subsequently to identify those sectors now occupied by advertising data, they have been assigned a state of E _PU B. The conventional exploitation of the memory by the user requires the recording of data in this memory. for example the copy of a file, the saving of parameters, the registration of registers for an application used by the user ... At first glance, this personal data may be recorded on the free space of the memory, so to keep a maximum of data. Nevertheless, it is noted that the purpose of recording advertising data is to exploit a large part of the free space of the memory and that the free space may be less than a threshold value, for example space required to register personal data. It is then necessary to record the personal data of the second type by overwriting a part of those of advertising. The overwritten memory sectors no longer contain advertising data. In this respect, the assigned EPUB status is removed: the system now detects only personal data in these areas. By symmetry, the absence of state E _P UB can be considered as the assignment of an E _PUB state to the personal data sectors.

Since the assignment and the withdrawal of the state E _PUB to the memory sectors takes place during the binary manipulation of the data, it appears appropriate to carry out a binary marking of this state. Thus, said erasable memory data sectors comprise a header comprising at least one B _PUB bit, said assignment of the E _PUB state to a sector consists in setting said B _P UB bit to a predefined V _PUB value, and said modification of the state of a sector consists in inverting or modifying the value of said bit. The change of state E _PUB is thus easily realized during the phases registration of the advertising data on the one hand, and personal data on the other hand.

Moreover, access to these bits B _P U _B for each sector of the memory can be expensive in terms of processing time for a computer system managing the memory. However, file manipulation by these systems is easier. Thus, said assignment of the state E _PUB to a sector comprises the recording of identification data of said sector in a table T _PUB , and said modification of the state of the sector comprises the withdrawal of said identification data of said table . This table can be initialized when the memory is turned on and can be a complement to the binary marking.

B _P UB memory sectors. This table includes, for example, the virtual sector numbers, the physical addresses of the sectors including advertising data of the first type or pointers to these sectors.

In addition, the memory sectors are of determined size, for example 512 bytes. The digital contents generally exceed this size and their recording is then performed on a set of memory sectors that are not necessarily contiguous. When advertising data (data of the first type) is recorded on several sectors and at least one of them is overwritten for the recording of personal data, all the digital content is no longer usable. It is then necessary to free the other uncrushed sectors and related to the same digital content. For this purpose, several sectors storing data of the first type are linked to the same digital content consisting of these stored data and the method comprises, during said subsequent write step, the modification of the state of the sectors linked to said associated sectors. to a state E _P U _B which are overwritten. Here we mean by "linked" sectors of memory whose data contained are usable only together. For example, an image file The size of a sector larger than the size of a sector is recorded in more than one related sector, and the E _PUB state is preferably changed from all sectors of the image file when one of them is overwritten. The use of file systems makes it possible in particular to maintain a table referencing these dependencies of several memory sectors to the same digital file.

The device comprising the memory has means for determining the list of linked memory sectors, that is to say composing the same digital content file. It may then appear appropriate, during the subsequent step of writing data of the second type, to constitute said portion of said sectors associated with a state E _PUB , that is to say the part of the sectors that will be overwritten , by linked memory sectors belonging to the same digital content or to a minimum of digital contents. This alters a minimum of digital content and minimizes the loss of exploitable data.

The conventional operation of a memory involves data access commands, for example a write WRITE command, a read READ command, an erase ERASE command, etc. These commands allow the manipulation of personal data. of the user and act on memory sectors identified as having data in operation. In order not to modify the operation of the memory with regard to the personal data, a second set of commands (for example WRITE _PUB for writing data by assigning the state E _PU B to the modified sector, READ _PUB to read the sectors to the state E _PU B, ERAS E _PU B, .- •) can be provided for handling advertising data, the sectors associated with the latter not being identified by conventional commands as simple personal data in operation. For this purpose, the steps of recording the data of the first type use commands different from those used for the recording of the data of the second type, these different commands automatically affecting the state E _PUB to the written data. Classic commands modify the state E _PUB when applied to advertising data areas in order to remove the E _PUB assignment to newly written areas with personal data.

In a variant according to which it is desired to keep the same set of conventional commands for handling both advertising data (of the first type) and personal data (of the second type), it may be provided that:

a device comprising said memory comprises data manipulation commands and has at least two operating states, a first state in which said commands automatically assign the state E _PUB to the manipulated data and a second state in which said commands deactivate or deny do not affect the E _PUB state of the manipulated data,

and, prior to the recording of the data of the first type, the method comprises a step of changing the state of the device comprising the memory in said first state and, prior to the recording of the data of the second type, a subsequent step of changing the state of the device including the memory in said second state.

This change of state is controlled by the computer system to which the device comprising the memory is connected. Generally, the assignment or the decommissioning of the state E _PUB is not carried out by a command in itself but it is the call to this command which conditions the modification of state.

On the other hand, it may be interesting to favor some advertising data over others in order to keep the first ones longer. Thus, during the recording of the data of the first type, a priority parameter, for example a bit field in the header of the sectors, is associated with the said sectors used, and the method comprises a step of selecting the said part of the data. sectors associated with an E _PUB state for recording the data of the second type, according to said sector priority parameters. More efficient management of the memory is thus obtained since the sectors linked to the same content have the same priority parameter and are therefore overwritten at substantially the same time, thus reducing the number of partially overwritten and unusable digital contents.

The subject of the invention is also a rewritable non-volatile memory device comprising a plurality of erasable data sectors, a device in which part of said sectors is initialized by the recording of data of a first type and each of these sectors used. is assigned to a state E _P U _B , and the device comprises means arranged to record data of a second type in at least a portion of said used sectors assigned to a state E _PU B when the free sectors of the memory have a space less than a threshold value and, to change the state of the sectors of said part.

It is also expected that several sectors storing data of the first type are linked to the same digital content consisting of these stored data and that said means arranged to modify the state of the sectors of said part are able to modify the state of the sectors related to sectors of that part, that is to say related to crushed sectors.

According to two embodiments that can be combined: said erasable data sectors of the memory comprise a header comprising a bit B _PUB , said bit B _PUB taking a value V _P U _B for a sector in the state E _P U _B and another value for another state, for example an inverse value V _PUB if there are two states E _PUB and E _PUB . said means adapted to modify the state of the sectors comprise a table T _PUB in which data of identification of the sectors of memory in the state E _PUB are recorded and are removed the identification data of the sectors that are no longer in the state E _PU B-

In one embodiment for the efficient operation of the memory, said means capable of modifying the state of the sectors comprise:

a memory microcontroller connected to said memory and able to drive said memory for data manipulation operations; and an application processor arranged to access said memory and said microcontroller and able to store said _PUB table.

Either the application processor is physically connected to the memory (to manipulate the advertisement data) and the microcontroller (to receive or issue requests concerning the advertisement data), or the application processor is physically connected to the microcontroller and accesses the memory via the microcontroller.

The microcontroller memory is a conventional microcontroller for memory management as there are many in the state of the art: it receives data access commands, translates them, accesses the memory and returns the data. accessed data. The latter has conventional commands for accessing data in memory and constitutes the interface between the non-volatile memory and a host device desiring to access this data, for example a personal computer to which the device comprising the memory is connected.

For its part, the application processor executes a firmware for the management of the personal data marked with the state E _P U _B - H stores the advertisement sectors via the table T _PUB and then carries out the operations of management of this data when access requests are issued or to record new advertising data in memory sectors left free. Optionally, the memory microprocessor and the application processor may be implemented by the same physical processor offering the two previously described features. In general, the means arranged for recording the data and modifying the state of the sectors may be implemented by a single processor, for example a smart card processor.

The application processor can also be implemented by a chip card processor independently of the microcontroller. The use of a smart card processor is advantageous in that it makes it possible to integrate mechanisms for securing access and processing the data stored in the memory.

Moreover, as mentioned previously, said means capable of modifying the state of the sectors can comprise two sets of commands, a first for the manipulation of the data of the first type affecting said E _PUB state to the manipulated data, and a second set for handling data of the second type without affecting said E _PUB state to the manipulated data. According to the desired configurations, the two sets of commands can be available by the microcontroller only, or the set of conventional commands is accessible by the microcontroller and the set of commands affecting the advertising data (of the first type) is managed by the processor. application.

Also, in the case where the memory has at least two operating states, said means capable of modifying the state of the sectors comprise: a memory microcontroller connected to said memory and having commands able to manipulate the data in the memory ,

means for modifying the state of the microcontroller between two states, a first state in which said commands automatically assign the E _PUB state to the manipulated data and a second state in which said commands disable or do not affect the E _PUB state of the manipulated data.

In one embodiment in which the advertisement data is prioritized to provide more efficient management of memory and data, the sectors comprising data of the first type further include priority data, and said device is arranged to select said portion of used sectors assigned to the state E _PUB according to said sector priority data.

According to different embodiments, the object of the invention is:

a USB key comprising a previously described device and a bus interface between said memory and an external device;

a chip card comprising an identical device, the application processor being a smart card module and the interface between the card and the host equipment being made by a reader with contacts or by wireless communication ("on the air")

- OTA);

a memory of the SDCard (Secure Digital Card) or MMC (Multimedia Card) type.

The invention also relates to a system comprising a memory device previously described and connected to a host device by means of a communication protocol, and a memory microcontroller, said host device comprising a file system for the management of said data of the second type and being able to manipulate said data of the second type by the use of said file system through usual commands of said memory microcontroller; and said host device being able to transmit to the memory device a command different from said usual commands to access the data of the first type.

In the solutions of the prior art, the host device d has a file system, for example a FAT (file allocation table), referencing the different digital files stored in memory as a list of memory sectors. used. When the host device accesses personal data, it determines the memory sectors associated with the FAT and then sends the data access commands to the memory microcontroller. In the invention, the host device may retain the same mechanism for accessing personal data. On the other hand, when it wishes to access advertising data, for example for viewing a movie trailer, it issues a different request that requires the interpretation of the microcontroller (or the application processor when it exists). ). The microcontroller can, for example, route a request of the FTP (file transfer protocol), Hypertext Transfer Protocol (HTTP), Network File System (NFS), or SMB (Server Message) type of request. Block) / CI FS (Common Internet File System) to the application processor, the latter acting as a file server for access to advertising data in the memory or for any application protocol access to a set of files. The different command previously mentioned can be, according to the embodiment chosen, a specific command dedicated to the manipulation of the data of the first type, a request to the microcontroller - more precisely the application processor - to recover data of the first type, a command of Flip the microcontroller into a state in which it can manipulate the data of the first type with the usual commands.

By keeping the traditional access mode to the personal data, the invention makes it possible to minimize the impacts on the embedded software environment of the host device. Moreover, the free space offered by the rewritable non-volatile memory should be exploited and made use of to the best of its ability. Two possibly complementary approaches can be used.

On the one hand, said memory device is arranged to transmit, when sectors of said memory are free, queries to a remote server for obtaining data of the first type and for recording said received data in said free sectors. In this so-called "pull" approach, the memory device will itself look for new advertising data on a remote server in order to exploit memory sectors left free. The memory device is informed by an appropriate event of an erasure operation of personal data in memory. When this event is detected, a comparison is made between the space of the free sectors and a certain predefined threshold, and a request for advertising contents is emitted according to the result of this comparison (generally if space of the free sectors ≤pre-defined threshold). On the other hand, the so-called "push" approach requires that said memory device is arranged to check, when it is requested by a remote server, the space formed by the free sectors of said memory and to record data. data of the first type provided by said server if they occupy a memory space less than a threshold value, for example the memory space of the free sectors. In this approach, the solicitation by the remote server may be periodic.

For the use of the system, the invention also relates to a method of operating a non-volatile memory in this system, the method comprising:

a data read request step of the first type by said host device; a step of interpreting said request by the memory device;

a step of identification, by said memory device, of sectors of memory associated with said data of the first type concerned by said request;

a step of reading, by said memory device, of said identified sectors;

a step of transmitting, from said memory device to said host device, data of the first type contained in said identified read sectors.

Either the identification of all the sectors is carried out before the read access of the memory (case of an application protocol, for example using the T _PUB table), or the access to the memory is realized. by sector by the specific commands, and to each of these sectors is applied the identification step and then the reading step if the identification is positive.

This method is combined with conventional methods for reading data in a non-volatile rewritable memory that is applied for reading personal data or data of the second type. The method thus described allows viewing of advertising data by the host device, for example for displaying an advertisement, a musical excerpt, etc. As mentioned above, the host device issues a request. requiring an interpretation by the microcontroller: the microcontroller or the associated application processor may be a server translating the HTTP request into memory access commands, a file server also translating the FTP request into similar commands, NFS requests, SMB ( CI FS), or other access protocols to files. The identification of the memory sectors concerned by the reading of the advertisement data is carried out by the detection of the sectors in the state E _P U _B by the use of the bit B _PU B and / or the table T _PUB - Specific commands or a change of state of the microcontroller then allow access to these data, then return them to the source host device of the initial request. In one embodiment relating to the access of the data of the second type (personal data) by the host device, the method further comprises a step of accessing data of the second type by said host device, this a step of determining by said file system the memory sectors containing the desired second-type data and accessing said memory sectors through said microcontroller.

The invention will be better understood with the aid of the detailed description below and the appended figures in which: FIG. 1 represents an exemplary system architect for the implementation of the present invention; FIG. 2 illustrates an exemplary implementation of the invention at the level of the memory sectors; and FIG. 3 is a timing diagram of an example of data exchanges according to the invention.

With reference to FIG. 1, a portable device 10 such as a USB key, an MMC card, or a disk, consists of:

• non-volatile memory 14;

a non-volatile memory controller 1 3 connected to the memory; An application processor 12 connected to the memory controller. Optionally, the application processor can be directly connected to the memory 14.

The system of the invention comprises a host device 1 1 (personal computer PC, mobile phone, etc.) to which is connected via a connection 1 5 high speed protocol such as USB, the portable memory device 10. Depending on the desired applications, it is anticipated that a card 10 equipped with a high-capacity memory 14 and a smart card processor 12 for a storage, exchange, application is connected to a personal computer 11. secure data. The chip card processor then has a separate physical connector (contact or contactless) and / or a specific low level communication protocol. A secure application can be the identification of people.

The memory controller manages the non-volatile memory by dividing it into two parts: a part containing conventional user data (work files, telephone book _ phone book_ for a mobile phone application, etc.) and a part containing promotional data. The distinction between the two types of data is carried out one level of each block or sector memory using an additional bit in the block header. In the example of FIG. 2, a field 20 of a memory sector 30 includes a first bit 22 to indicate whether the data contained 21 is promotional or not (value "1" if the data is promotional) and a second bit. , known from the prior art, to indicate whether the data sector is free (value "1") or used (value "0").

The sectors constituting the two parts are not necessarily contiguous. When multiple sectors are used to store data from the same digital content, they are also not necessarily contiguous.

Traditional mechanisms, for example those used to access the data of a traditional USB memory stick, are used to manage the data of the user and in particular to allow their access to the host device 1 1. When the portable device 10 is connected to the host device 1 1, the latter establishes a file allocation table (FAT - File Allocation Table) and keeps it up to date according to the operations performed. This table lists all the data sectors user (field 20 having the value "00") and to link the sectors belonging to the same digital content (for example the same file). In operation, when the host device wishes to access a digital file, it determines through this table FAT all the useful memory sectors and then accesses via the microcontroller 13.

The sectors not indicated in this table (free sectors and promotional sectors) are not seen the host device as being free and therefore usable at any time for the storage of personal data. Blocks marked as containing promotional content are taken into account in the calculation of the amount of available memory and appear as free from the point of view of the host.

The portion of the memory containing the promotional content is managed entirely by the application processor in a method that may be conventional or proprietary, which is of little importance because the host device does not access it directly. The application processor executes an application program that fulfills two functions:

on the one hand, nonvolatile memory management functions with regard to the promotional data by sending manipulation commands (write, read, delete, etc.) via the microcontroller, on the other hand, intermediary functions between the host device and the promotional data in memory, by implementing server functions for example files.

Like the FAT table used by the host device, the application processor can maintain an equivalent T _PUB table referencing the memory sectors containing advertising data.

The memory 14 is initially filled with promotional contents, by recording the advertising data in the sectors memories. Several promotional contents are recorded until the space occupied by the free sectors (field 20 having the value 11 or 01) is less than a threshold value. We can actually wish to keep a minimum (for example 5 or 10%) of the memory as completely free (this is the case generally for flash memories in which it is necessary to keep free sectors to proceed with initialization operations and displacement of memory sectors). It can also be expected that the digital contents are hierarchical from most important to least important. The digital data of the most important contents are recorded first. The initialization of the memory is stopped when the space required for the recording of the next digital content is greater than the space still available either in the memory or to reach the previous threshold value.

The memory sectors are also provided with a binary field indicating a weight (representative of the hierarchy of contents). Since no personal data is stored on the memory, the host device sees the memory as completely empty.

The host device 11 accesses the promotional data by communicating with the file server of the application processor according to the HTTP protocol. HTTP requests are transported in IP (Internet Protocol) packets transmitted over connection 15.

FIG. 3 illustrates these exchanges: step 1: the host 11 sends, by a client application, an HTTP request on a promotional content, for example; "HTTP GET Clip.avi";

"Step 2: this request is routed by the memory controller 13 to the application processor 12; β step 3: the HTTP request is decoded by the file server of the application processor which locates the corresponding blocks in the non-volatile memory, for example using the table TPUB - U once the memory sectors identified, the processor application makes the read requests associated with the memory controller; Step 4: The memory controller 13 transmits the read requests to the nonvolatile memory 14. If necessary, the controller translates requests from the application processor into appropriate read / write / erase commands for r access the data in memory;

Step 5: the read commands return the desired data to the memory controller, which is routed to the application processor (step 6); • Step 7 and 8: The application processor formats a response with the read data that has been requested by the host, for example the HTTP response "HTTP 200 OK" followed by the read data, if all went well. Then it passes this response to the client of a host device via the memory controller.

The memory 14 also serves as a means of storing the data of the user.

The host device requests to write personal user data into memory by traditional mechanisms. When the free space is insufficient (intrinsically or with respect to a threshold value of free sectors to keep), the present invention provides for erasing promotional data.

Receiving the request to write the host device, the memory controller sends a request to the applicative processor specifying the space required: space of the personal data to be written less possibly free sectors available (for example, secteu rs containing data that are no longer used). The application processor selects the memory sectors allocated min imum weights (numeric contents less important). Thanks to the T _PUB table, the application processor preferably selects the sectors linked to the same content in order to alter the minimum of digital contents. It communicates these sectors to the memory controller. With reference to FIG. 2b, for each sector thus selected, the bit of the field 20 specifying the promotional nature of the data is set to "0". The sectors are no longer promotional sectors but personal content. Then the personal data are recorded in these sectors by conventional commands for writing in memory.

Thus the writing of personal data has deleted one or more promotional digital content (s). However, all the memory sectors that were dedicated to a promotional content thus deleted have not necessarily been used or selected by the application processor. Since the data of these unselected sectors are no longer usable, the application processor also issues a request to release these sectors, for example by modifying the bit of the field 20 indicating the promotional nature of the data to the value "0" and modifying a bit 24 of validity of the data (known from the prior art) to a value "0" (obsolete data). These sectors can also be marked as free (field 20 takes the value "01").

Upon receipt of the write confirmation, the host device updates its FAT table.

It is also possible, preferably with the use of weights, to select the areas to be crushed (to be released) so as to minimize the lost sectors (that is, the released and uncrushed data sectors). The application processor then determines a set of digital contents (sometimes reduced to only one) whose dedicated memory space is substantially equal (in any case greater than or equal to), or as close as possible to the space required for the data. to register. When the host device requests deletion of data in memory, free sectors are now available to accommodate new promotional data.

In a "pull" filling mode, the erasure of data in memory by the memory controller generates an event for the application processor. The latter can determine the free memory space (if the event does not indicate it) and issue an HTTP request to a remote server of promotional content accessible (directly or via the host device) by a communication network. In response to this request, the server returns promotional content corresponding to the usable free space.

In a "push" filling mode, the preceding remote server sends an HTTP request to the application processor. By this request, the application processor determines the free space available in the memory 14 for the possible backup of new promotional data. The application processor then saves the promotional content provided by the remote server.

Claims

A method of managing a rewritable non-volatile memory comprising a plurality of erasable data sectors, the method comprising a step of storing data of a first type in at least a portion of the free sectors of the memory, characterized in that it comprises:

an initialization step of assigning an E _PUB state to each of said sectors used so as to distinguish between the data of said first type and data of a second type, and

a subsequent step of writing said data of said second type into the memory consisting, if the free sectors of the memory have a space less than a threshold value, of recording said data of the second type on a part of said sectors associated with a state E _PUB , and to change the state of these sectors.

A method of managing a memory according to claim 1, characterized in that said erasable data sectors of the memory comprise a header comprising at least one B _PU B bit, said assignment of the E _PUB state to a sector consists in putting said bit B _PUB to a predefined value V _PUB , and said modification of the state of a sector consists in inverting the value of said bit.

The memory management method as claimed in claim 1, wherein said assignment of the state E _PU B to a sector comprises the recording of identification data of said sector in a table T _PUB , and said modification of the state of the sector comprises the withdrawal of said identification data from said table.

4. Memory management method according to any one of the preceding claims, characterized in that several sectors storing data of the first type are linked to the same digital content consisting of these stored data and in that it comprises, during said subsequent write step, modifying the state of the sectors related to said sectors associated with an E _PUB state which are overwritten.

5. Management method of a memory according to the preceding claim, characterized in that, in the subsequent step of writing data of the second type, said part of said sectors associated with an E _PUB state is constituted by memory sectors. linked.

6. A method of managing a memory according to any one of the preceding claims, characterized in that the steps of recording data of the first type use commands different from those used for the recording of data of the second type. , these different commands automatically affecting the E _PUB state to the written data.

7. A method of managing a memory according to any one of claims 1 to 5, characterized in that a device comprising said memory comprises data manipulation commands and has at least two operating states, a first state in wherein said commands automatically affect the state E _P U _B to the manipulated data and a second state in which said commands disable or do not affect the E _PUB state of the manipulated data, and in that it comprises, prior to the recording the data of the first type, a step of changing the state of the device comprising the memory in said first state and, prior to the recording of the data of the second type, a subsequent step of changing the state of the device comprising the memory in said second state.

8. Memory management method according to any one of the preceding claims, characterized in that, during the recording of the data of the first type, a priority parameter is associated with said sectors used, and in that comprises a step of selecting said part of the sectors associated with a state E _PUB> for the recording of the data of the second type, according to said priority parameters of the sectors.

A rewritable non-volatile memory device comprising a plurality of erasable data sectors, characterized in that a portion of said sectors is initialized by the data record of a first type and each of these used sectors is assigned to a E _PUB state, so as to distinguish between the data of said first type and data of a second type, and in that it comprises means arranged to record said data of said second type in at least a portion of said used sectors assigned to a state E _P UB when the free sectors of the memory have a space less than a threshold value and, to change the state of the sectors of said part.

10. Device according to the preceding claim, characterized in that several sectors storing data of the first type are linked to the same digital content consisting of these stored data and said means arranged to change the state of the sectors of said part are able to modify the state of the sectors related to the sectors of that part.

11. Device according to claim 9 or 10, characterized in that said erasable data sectors of the memory comprise a header having a B _PUB bit, said B _PUB bit taking a V _PUB value for a sector in the state E _PUB and another value for another state.

12. Device according to one of claims 9 to 1 1, characterized in that said means adapted to change the state of the sectors comprise a table T _PUB in which are stored identification data memory sectors in the state E _PUB and are removed the identification data of sectors that are no longer in the state E _PUB -

13. Device according to claim 12, characterized in that said means adapted to modify the state of the sectors comprise: - a memory microcontroller connected to said memory and adapted to drive said memory for data manipulation operations; and

an application processor arranged to access said memory and said microcontroller and capable of storing said _PUB table;

14. Device according to any one of claims 9 to 13, characterized in that said means arranged to record the data and change the state of the sectors are implemented by a single processor.

15. Device according to any one of claims 9 to 14, characterized in that said means capable of modifying the state of the sectors comprise two sets of commands, a first for handling data of the first type affecting said state E _P UB to manipulated data, and a second set for handling data of the second type without affecting said E _PUB state to the manipulated data.

16. Device according to any one of claims 9 to 14, characterized in that said means capable of modifying the state of the sectors comprise:

a memory microcontroller connected to said memory and having commands able to manipulate the data in the memory,

means for modifying the state of the microcontroller between two states, a first state in which said commands automatically assign the state E _PU B to the manipulated data and a second state in which said commands deactivate or do not affect the state E _PUB manipulated data.

Device according to any one of claims 9 to 16, characterized in that the sectors comprising data of the first type further comprise priority data, and in that said device is arranged to select said part of sectors. used in the state E _PU B according to said sector priority data.

18. Device according to any one of claims 9 to 17, characterized in that said means arranged to record the data and change the state of the sectors are implemented by a chip card processor.

19. USB stick comprising a device according to any one of claims 9 to 18 and a bus interface between said memory and external equipment.

20. System comprising a memory device according to any one of claims 9 to 18 connected to a host device by means of a communication protocol and a memory microcontroller, said host device comprising a file system for the management of said data from the second type and being able to manipulate said data of the second type by the use of said file system through usual commands of said memory microcontroller; and said host device being adapted to transmit to the memory device a command different from said usual commands to access the data of the first type.

21. System according to claim 20, characterized in that said memory device is arranged to transmit, when sectors of said memory are free, requests to a remote server for obtaining data of the first type and for recording said received data. in said free sectors.

22. System according to claim 20 or 21, characterized in that said memory device is arranged to check, when requested by a remote server, the space formed by the free sectors of said memory and to record data of the first one. type provided by said server if they occupy a memory space less than a threshold value.

23. A method of operating a non-volatile memory in a system according to any one of claims 20 to 22, characterized in that it comprises:

a data read request step of the first type by said host device;

a step of interpreting said request by the memory device;

a step of reading, by said memory device, of said identified sectors; a step of transmitting, from said memory device to said host device, data of the first type contained in said identified read sectors.

24. The method as claimed in claim 23, characterized in that it further comprises a step of accessing data of the second type by said host device, this step of determining by said file system the sectors of memory containing said desired second type data and accessing said memory sectors through said microcontroller.