JPH0561760A - Storage management system for memory card - Google Patents

Abstract

PURPOSE:To apply a memory allocation table(MAT) system even at a non- volatile memory such as an EEPROM or the like in a batch erase system or a partial erase system for the unit of a block. CONSTITUTION:A memory card 11 equipped with a storage area 60 of the EEPROM is provided with plural header blocks 33 to be respectively recorded with header information related to the storage of image information and a header information pointer 36 to display whether each header block 33 is vacant or occupied. By turning-on a power source, a host such as a digital electronic still camera 10 or the like reads the header information from the latest header block 33 indicated by the pointer 36 to a memory 14. The image information is written in the EEPROM storage area 60, and the header information in the memory 14 is updated. When the operation of turning-off the power source of the host 10 is executed, the host 10 reads the header information from the memory 14 and writes this information in the header block 33 whose vacant state is displayed by the pointer 36, and the display corresponding to the header block 33 with this information written is turned to the occupied state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage management system for a memory card, and more particularly to an erasable programmable read-only memory (EPROM) or an electrically erasable programmable read-only memory (EEPROM). The present invention relates to a storage management method of a memory card having a read-only storage device as a storage area.

[0002]

2. Description of the Related Art For example, a conventional memory card used as a storage medium for image data in a digital electronic still camera has a storage area of SRAM. SRAM requires a power supply circuit for backup and has a drawback that the unit price of bits is expensive. In recent years, a memory card having an EEPROM as a storage area, which does not require battery backup and can be electrically erased in block units or in a batch, has been put into practical use, and can have a capacity of about 1 Mbit. Such an EEPROM may be used in place of a SRAM memory card.

For example, in the memory management system of the memory card described in Japanese Patent Application No. 2-60927, which is a patent application filed by the same applicant as this application, one frame of image data is stored in the memory area of the EEPROM of the memory card. Takes the form of one packet. One packet of image data is generally distributed and accumulated in a plurality of clusters, which are the minimum management units of the memory.
These clusters are managed by a memory allocation table (MAT) for each packet. In other words, when the image data of one packet is distributed and stored in multiple clusters, the relation of the first cluster related to the packet is defined by MAT, and the subsequent image data is stored at the end of the first cluster. The identification information of the current cluster is stored, and the relationship of being one packet of image data is defined by forming a chain following a plurality of clusters from such MAT. Management information for managing these clusters and packets is stored in the header area of the memory card. The header is provided for each memory card, and management information such as the packet number, the head cluster number of the packet, the number of used clusters, and the number of remaining clusters is written in the header. Therefore the header is 1
Each time the packet image data is written to the storage area,
Contents are updated. Such management of the memory area by the MAT method is advantageous for storage of data such as image data whose data length is not fixed, because there is no limit to cluster allocation.

[0004]

As for the EEPROM, the batch erasing method and the block erasing method are generally advantageous in terms of cost. Also, the rewriting limit is about 100 to 1000 times. The MAT method as described above is originally suitable for a rewritable storage device such as SRAM because the header area needs to be constantly updated. However, it is not suitable as it is for a batch erasing method or a block erasing method EEPROM.

In view of such demands, it is an object of the present invention to provide a memory management system of a memory card to which a MAT system can be applied even in a non-volatile memory such as a batch erasing system or a block unit partial erasing system EEPROM. To do.

[0006]

According to the present invention, there is provided a storage management system for a memory card having a storage area of an EEPROM in which a record is erased in a predetermined logical state in initialization and information is additionally written therein. A plurality of header recording areas provided in the storage area, in which header information including at least a part of management information for storing image information is recorded, and a plurality of header recording areas provided in the storage area About the sky block display means to display the sky block,
The image information is written in the storage area, and at the first time, the header information relating to the image information is written in the empty header recording area indicated by the empty / closed display means among the plurality of header recording areas, and the written header in the empty / closed display means is written. And a control unit for closing the display corresponding to the recording area.

According to the present invention, the memory card storage management system further comprises a header recording area provided in the storage area, in which header information including at least a part of management information relating to storage of image information is recorded. A plurality of storage position indicating areas for additionally instructing a storage position in the storage area in which a header recording area is formed, and an area provided in the storage area and having the latest instruction among the plurality of storage position indicating areas And the image information is written in the storage area, and at the first time point, the area to which the latest instruction has been added among the plurality of storage position pointing areas based on the instruction means is referred to and referred to. Control means for deriving a position in the storage area designated by the storage location designating area, and writing header information relating to image information in the header recording area at the location thus derived; Including.

[0008]

According to the present invention, the control means, at the second time point,
The header information is read from the latest header recording area instructed by the empty / closure display means into the storage means. The image information is written in the storage area, and the header information in the storage means is updated. At the first time point, the control means reads the header information from the storage means, writes it in the header recording area in which the empty / occluded display means displays an empty area, and closes the display corresponding to the written header recording area. To do.

Further, according to the present invention, the control means derives the position in the storage area to be instructed by referring to the area to which the latest instruction has been added in the plurality of storage position instructing areas based on the instructing means. Header information relating to image information is written in the header recording area at the derived position.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a memory card storage management system according to the present invention will now be described in detail with reference to the accompanying drawings. Figure 2
An embodiment in which the present invention is applied to a digital electronic still camera is shown in FIG. In this embodiment, a memory card 11 is detachably connected to a digital electronic still camera 10 via a connector 12. The camera 10 functions as a host for the card 11 and has a functional unit such as a solid-state imaging device necessary for photographing, but only a portion necessary for understanding the present invention is shown in order to avoid complication of the description. There is. The camera 10 has a system controller 13 for controlling the entire functions of the camera such as shooting with an image pickup device and a memory 14 as a work area thereof, and these are connected to each other by a bus 15. The bus 15 is connected to the connector 12 via a card interface 16 that interfaces with the memory card 11.

The memory card 11 is a camera in this embodiment.
A storage area 60 of an EEPROM is provided as a storage area for non-volatilely accumulating image data representing the image captured in 10 together with related data. The EEPROM storage area 60 is advantageously applied to a batch erase type or a partial erase type such as block erase. Writing, reading, and erasing to the storage area 60 are performed by the memory controller 40 under the control of the system controller 13 of the camera, that is, the host 10. The memory controller 40 connects the camera 10 via the interface 45.
Connected to the card interface 16. The memory controller 40 is also connected to the buffer memory 50 and controls writing and reading of the buffer memory 50 from the camera 10 side. The EEPROM storage area 60 has a relatively low access speed, and is not sufficient for inputting image data by continuous shooting of the camera 10, for example. Therefore, in this embodiment,
An SRAM buffer memory 50 is provided, and writing to the EEPROM storage area 60 is performed via this.

The structure of the EEPROM storage area 60 is illustrated in FIGS. 1, 3 and 4. When this storage area 60 is initialized, all storage units are set to binary "1", that is, to hexadecimal "F". Of course, the present invention is effectively applied to an EEPROM of the type initialized to "0". In the present embodiment, generally, the data is not rewritten in the storage area 60, and an additional writing method is used in which new data is written in a storage area different from the existing storage area in which the data is already stored.

Storage area 60 of the memory card 11 from the camera 10
As described above, the data to be written in is the management data such as the directory and the memory allocation table (MAT) in addition to the image data. This management data is
It must be updated each time a picture is taken with the camera 10. However, in the normal case, the image data may be additionally written to a new area in the storage area 60.

The storage area 60 is managed by the unit storage area, that is, the cluster 21, which is the minimum management unit described above. As can be seen from FIG. 3, the storage area 60 has a predetermined storage capacity,
For example, it is composed of multiple clusters 21 each having a size of 8 Kbytes. A particular cluster of those clusters 21,
In this embodiment, the cluster # 1 is an area in which management data is written. Image data is written in other clusters, that is, clusters after # 2.

As shown in FIG. 1, the cluster # 1 includes a header area 28 in which management data is written, a packet identification area 22 in which identification information such as a packet number for identifying one packet of image data is written, and a user. Is a directory area 24 in which a start cluster number and a data type for editing and reproducing the image frames, that is, packets in a desired order, and a cluster for each packet
21 is associated with the packet, that is, the MAT area 26 in which the MAT data indicating the address in the storage area 60 of the cluster 21 associated with the packet is recorded. In the latter four storage areas 22, 24 and 26, information is written in new areas each time the image is taken by the camera 10, and in the illustrated example, the remaining areas 23, 25 and 27 are unused.

In this embodiment, the header area 28 is provided with a 16-byte unit header recording area, that is, a header block area 34 in which a header block 33 is formed, and a 192 byte header information pointer 36. Header block area
34 has a storage capacity of 1536 bytes in this embodiment, so that 94 header blocks 33 can be written. Each of the header blocks 33 has a storage area in this embodiment.
The number of used or used clusters, the number of unused or remaining clusters in 60,
This is an area in which header information 30 such as the last used packet number, the first unused cluster number, and the parity check code is written. For details of such a memory management method by the MAT method, refer to the pending patent application by the same applicant as this application, Japanese Patent Application No. 1-317796.

The characteristic feature of this embodiment is that the camera
When a specific memory card 11 is connected to the connector 10 by the connector 12 and the camera 10 is powered on, the latest data of the header block 33 in the header area 28 is read into the memory 14 of the camera 10 and shooting is performed. When this is updated in the memory 14 and the power of the camera 10 is turned off, the system controller 13 of the camera 10 responds to this by reading the header information from the memory 14 and writing it in the new header block 33. Is. As can be seen from the above description, the minimum amount of data to be written in the header block 33 is desirable. This makes it possible to effectively increase the number of times the power of the camera 10 is turned off for one memory card 11. The updating of the header block 33 will be described later in detail.

The header information pointer 36 is an empty / closed display area for designating the header block in which the latest header information is written among the plurality of header blocks 33 in the header block area 34. In this embodiment, the header information pointer 36 is
Using a 192 byte storage area, the binary "0" bit position at the rightmost bit position in FIG. 4, that is, the position closest to the least significant digit is the header in which the latest header information is recorded. Point to block 33. In the example shown,
Since it is a binary "0" from the left to the third bit position of the header information pointer 36, the header block # 3 having the number 3
Indicates that it carries the latest header information.
Of course, in order to display the empty / closed state or the latest recording state or recording order of the header block 33, another method such as providing a display bit in each header block 33 may be used without taking the form of such a pointer. ..

As described above, in the initialization for erasing all the record information in the storage area 60, all the record information in the block area 34 of the header area 28 is erased, and each bit of the header information pointer 36 is also erased. Are all "1". Therefore, the first header information sent from the camera 10 when the power of the camera 10 is turned off is written in the header block # 0. After that, each time the power is turned off, the updated header information
It is written in order of 1, # 2, # 3. Corresponding to this writing, the bit "1" of the header information pointer 36 is inverted to "0" in order from the most significant digit, that is, the head, each time. Therefore, the first bit "0" as viewed from the left of FIG. 4 indicates the number of the header block 33 of the latest information. Therefore, the logical state of the header information pointer 36 in FIG. 4 indicates that the latest header information is written in the header block # 3 shown in FIG. In the embodiment shown in FIG. 1, the EEPR in which the bit becomes "1" at initialization
Although the OM is used, if the value becomes "0" at the time of initialization, the bit value of the header information pointer 36 is reversed, and the rightmost "1" indicates the latest header block 33 number. ..

A memory card 11 is attached to the camera 10,
When the power of the camera 10 is turned on, the system controller 13 of the camera 10 responds to this and outputs a command to read the header 28 from the storage area 60 of the memory card 11. This read command is transferred to the memory controller 40 through the bus 15, the card interface 16, the connector 12 and the interface 45 on the card 11 side. Memory controller 40
In response to this, the header information of the header block 33 corresponding to the rightmost bit “0” of the header information pointer 36 is read and output to the interface 45. The system controller 13 of the camera 11 receives this header information,
It is stored in the memory 14.

The system controller 13 of the camera 10 then updates this header information in the memory 14 each time an image is taken. Along with this, the system controller 13
Outputs one frame, that is, one packet of image data, the address of the cluster to be stored, and their supplementary information. The memory controller 40 receives this via the interface 45, temporarily stores these image data and management information in the buffer memory 50, then reads them from this, and the directory area according to the designated address.
The directory data is written in 24, the MAT data is written in the MAT area 26, and the image data is written in other cluster areas.

When the user finishes photographing and turns off the power, the system controller 13 of the camera 10 reads the header information from the memory 14 and outputs it to the memory card 11 through the card interface 16. Upon receiving this, the memory controller 40 receives the buffer memory.
Accumulate at 50 once. After that, the header information pointer 36 is checked, and the header information is read from the buffer memory 50 and written in the first header block 33 corresponding to the leftmost bit "1". At the same time, the memory controller 40 inverts the leftmost bit of the header information pointer 36, that is, the first bit "1" to "0". Each time the header information is input in this way, the memory controller 40
The same operation is repeated to write the latest header information in the new header block 33. In this embodiment, when the power of the camera 10 is turned off, the updated header information is written in the new header block 33. However, it may be configured to write in the new header block 33 after a lapse of a predetermined number of times of shooting, for example, every time of shooting.

FIG. 5 shows another embodiment of the present invention. In the embodiment shown in FIG. 1, the area in which the header information is stored is limited to the specific cluster # 1. However, in this method, in the case of a memory card using EEPROM with a large storage capacity,
The number of times the header information is updated increases, so that the capacity of the area 28 that can be used as the header area may be insufficient. The embodiment shown in FIG. 5 is a method of solving this, in which the header area 28 in which the header information is to be written is formed in an arbitrary cluster 21, and a cluster recorded in the header area 28 in a specific cluster, for example, cluster # 1. An area 81 for writing the number 21 is provided, and the intended header area 28 can be accessed by additionally writing the area 81.
More specifically, the cluster number area 81 is written with the number of the cluster 21 in which the header area 28 is formed, and indicates the cluster 21 including the latest header area 28.
81 is designated by the pointer 82. That is, the cluster number area 81 is updated and additionally written similarly to the header block 33 in the embodiment shown in FIG.
Functions similarly to the header information pointer 36 in the embodiment shown in FIG. The cluster number in the cluster number area 81 is converted into a cluster address in the storage area 60 by the cluster number table 84, and the cluster 21 having the intended header area 28 is accessed by this cluster address.

When the power of the camera 10 is turned on, first, the specific area 80 is accessed and the number of the cluster 21 in the latest header area 28 is searched by the pointer 82 and the cluster number area 81. Information of the latest header block 33 from the latest header area 28 is fetched into the memory 14 according to this cluster number, for example, a1. This operation is similar to that of the embodiment shown in FIG. When the header information is written in the header area 28, the latest header area 28 is accessed in the same manner, and the pointer 36 is referred to write the header information in the unused block 33. In this method, when the writing of information to the new header block 33 in one cluster 21 becomes impossible, the header area 28 can be used extensively by setting the header area 28 in the other cluster 33.

[0025]

As described above, according to the present invention, even in a memory card using a batch erasing method or a block erasing method EEPROM, the header data, which is frequently rewritten, is additionally written in a plurality of areas. , The memory management method including the current SRAM card header, directory and MAT can be applied. Therefore, it is possible to realize an EEPROM or EPROM memory card that has format compatibility, can be used like an SRAM card, and consumes less power than an SRAM card.

[Brief description of drawings]

FIG. 1 is a diagram exemplifying a configuration of a storage area for management data in the embodiment shown in FIG.

FIG. 2 is a functional block diagram showing an embodiment in which a memory card storage management system according to the present invention is applied to a digital electronic still camera.

FIG. 3 is a diagram showing an example of a configuration of a storage area in the embodiment shown in FIG.

FIG. 4 is a diagram showing an example of the configuration of a header information pointer in the embodiment shown in FIG.

FIG. 5 is a diagram illustrating a configuration of a storage area for management data according to another embodiment of the present invention.

[Explanation of symbols]

 10 Digital electronic still camera 11 Memory card 13 System controller 14 Memory 21 Cluster 28 Header area 33 Header block 36 Header pointer 40 Memory controller 50 Buffer memory 60 EEPROM storage area

Claims (5)

[Claims] 1. A storage management system for a memory card having a storage area of an EEPROM in which a record is erased to a predetermined logical state in initialization and information is additionally written to this,
The method includes a plurality of header recording areas provided in the storage area, in which header information including at least a part of management information related to storage of image information is recorded, respectively, and a plurality of header recording areas provided in the storage area. An empty block display means for displaying an empty block for each of the recording areas, and writing the image information in the storage area, and at a first point of time, header information relating to the image information is recorded in the empty block of the plurality of header recording areas. A storage management system for a memory card, comprising: a control means for writing in an empty header recording area indicated by the display means and for closing a display corresponding to the written header recording area in the empty / closed display means. 2. The method according to claim 1, wherein the control unit has a storage unit that rewritably stores the header information, and the control unit has a second time point different from the first time point. so,
The header information contained in the most recently written recording area of the plurality of header recording areas is read out from the plurality of header recording areas and accumulated in the storage means, and the header information accumulated in the storage means is read out. A memory card storage management method characterized by constantly updating. 3. A storage management system for a memory card having an EEPROM storage area in which a record is erased to a predetermined logical state in initialization and information is additionally written to this,
The method includes a header recording area provided in the storage area, in which header information including at least a part of management information for storing image information is recorded, and a storage position in the storage area in which the header recording area is formed. A plurality of storage position indicating areas for additionally instructing, and an instructing unit provided in the storage area for instructing an area to which the latest instruction is added among the plurality of storage position indicating areas; Writing to a storage area, at the first point of time, referring to the area of the plurality of storage position pointing areas to which the latest instruction has been added, based on the pointing means, the storage indicated by the referenced storage position pointing area And a control unit for deriving a position in the area and writing header information relating to the image information in the header recording area at the derived position. Memory management method of the. 4. The method according to claim 3, wherein the header recording area has a first plurality of recording areas in which the header information is recorded and a blank area is filled in each of the first plurality of recording areas. And a second recording area to be displayed, wherein the control means, at a first time point, stores header information relating to the image information in an empty recording area indicated by the second recording area among the first plurality of recording areas. A storage management method for a memory card, characterized in that a display corresponding to the written first recording area in the second recording area is closed and displayed. 5. The method according to claim 4, wherein the control unit has a storage unit that rewritably stores the header information, and the control unit has a second time point different from the first time point. so,
Based on the instruction of the instructing means and the display of the second recording area, the header information included in the most recently written recording area of the first plurality of recording areas is read out and stored in the storage means. A memory card storage management method characterized by constantly updating header information accumulated in a storage means.