JP3070994B2 - Memory card storage management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage management method for a memory card, and more particularly to an erasable programmable read only memory (EEPROM) such as an erasable programmable read only memory (EPROM) and an electrically erasable programmable read only memory (EEPROM). The present invention relates to a storage management method for 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. The SRAM requires a power supply circuit for backup, and has a disadvantage that the unit cost per bit is high. 2. Description of the Related Art In recent years, a memory card using an EEPROM as a storage area that does not require a battery backup and can be electrically erased in blocks or collectively has been put into practical use, and a memory card having a capacity of about 1 Mbit can be realized. Such an EEPROM may be used in place of an SRAM memory card.

For example, in a memory management method of a memory card described in Japanese Patent Application No. 2-60927 by the same applicant as the present applicant, one frame of image data is stored in an EEPROM storage area of the memory card. Takes the form of one packet. In general, one packet of image data is distributed and stored in a plurality of clusters, which are minimum management units of a memory.
These clusters are managed in a memory allocation table (MAT) for each packet. That is, when one packet of image data is distributed and stored in a plurality of clusters, the association of the first cluster for 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 cluster that is present is stored, and the relevance of being one packet of image data is defined by forming a chain following a plurality of clusters from such a MAT. Management information for managing these clusters and packets is contained in the header area of the memory card. The header is provided for each memory card, and management information such as a packet number, a leading cluster number of the packet, the number of used clusters, and the number of remaining clusters is written therein. Therefore, the header is 1
Each time the packet image data is written to the storage area,
The content is updated. The management of the memory area according to the MAT method is advantageous because there is no restriction on the assignment of clusters for storing data whose data length is not fixed, such as image data.

[0004]

Generally, in the EEPROM, a batch erasing method and a partial erasing method in block units are advantageous in terms of cost. The rewriting limit is about 100 to 1000 times. The above-described MAT method is always suitable for a rewritable storage device such as an SRAM because the header area must be constantly updated. However, it is not suitable as it is for the EEPROM of the batch erasing method or the partial erasing method of the block unit.

The present invention has been made in view of such a demand, and has as its object to provide a storage management method for a memory card to which the MAT method can be applied even to a nonvolatile memory such as an EEPROM of a batch erasing method or a partial erasing method in block units. I do.

[0006]

According to the present invention, there is provided a storage management system for a memory card having an EEPROM storage area in which a record is erased to a predetermined logical state at the time of initialization and information is additionally written into the memory. A plurality of header recording areas provided in the storage area, each recording header information including at least a part of management information relating to storage of image information; and a plurality of header recording areas provided in the storage area, respectively. Air / fence display means for displaying air / fence about,
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 / busy display means among the plurality of header recording areas, and the header written in the empty / busy display means is written. Control means for closing the display corresponding to the recording area to make the display closed.

According to the present invention, a storage management method for a memory card includes a header recording area provided in the storage area and recording header information including at least a part of management information relating to storage of image information; A plurality of storage position indication areas for additionally indicating storage positions in the storage area in which the header recording area is formed; and an area provided in the storage area and among the plurality of storage position indication areas to which the latest instruction is added And the image information is written into the storage area, and at the first time point, the area to which the latest instruction has been added in the plurality of storage position instruction areas is referred to based on the instruction means, and this reference is made. Control means for deriving a position in the storage area indicated by the storage position instruction area, and writing header information relating to image information in a header recording area of the position thus derived; Including.

[0008]

According to the present invention, the control means, at the second time,
The header information is read from the latest header recording area instructed by the air / occlusion display means into the storage means. The image information is written in the storage area, and the header information of the storage means is updated. At a first point in time, the control means reads the header information from the storage means, writes the header information in the header recording area where the empty / busy display means is displaying the empty state, and changes the display corresponding to the written header recording area to the closed display. I do.

According to the present invention, the control means refers to the area in the plurality of storage location indication areas to which the latest instruction has been added based on the indication means, and derives the position in the storage area to be designated. The header information relating to the image information is written in the header recording area at the derived position.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a memory card storage management system according to the present invention. FIG.
Next, an embodiment in which the present invention is applied to a digital electronic still camera will be described. 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 shooting, but in order to avoid complicating the description, only a part necessary for understanding the present invention is shown. I have. The camera 10 has a system controller 13 for controlling the entire functions of the camera, such as photographing by an imaging device, and a memory 14 as a work area thereof, and these are interconnected 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.

In this embodiment, the memory card 11 is a camera.
An EEPROM storage area 60 is provided as a storage area for non-volatile storage of image data representing the image captured in 10 together with its associated data. As the EEPROM storage area 60, a partial erase type such as a batch erase type or a block erase is advantageously applied. Writing, reading, and erasing of 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 controls the camera 10 via the interface 45.
Is 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. The EEPROM storage area 60 has a relatively low access speed, and is not enough to respond to input of image data by continuous shooting of the camera 10, for example. Therefore, in the present embodiment,
An SRAM buffer memory 50 is provided, through which writing to the EEPROM storage area 60 is performed.

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

The storage area 60 of the camera 10 to the memory card 11
As described above, data to be written into the memory includes management data such as a directory and a memory allocation table (MAT) in addition to the image data. This management data
It must be updated each time a picture is taken by 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 a 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 a plurality of clusters 21 having a size of 8 Kbytes. Specific clusters among those clusters 21,
In this embodiment, cluster # 1 is an area where management data is written. Image data is written to other clusters, that is, clusters after # 2.

As shown in FIG. 1, 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 a frame of an image, that is, a packet in a desired order, and a cluster for each packet.
MAT area 26 in which the MAT data indicating the address in the storage area 60 of the cluster 21 related to the packet is recorded. In the latter four storage areas 22, 24 and 26, information is written in new areas each time shooting is performed by the camera 10, and in the example shown, the remaining areas 23, 25 and 27 are unused.

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

The 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 turned 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 the photographing is performed. When this is updated in the memory 14 and the operation of turning off the power of the camera 10 is performed, the system controller 13 of the camera 10 reads the header information from the memory 14 in response thereto and writes the header information into the new header block 33. It is. As can be seen from the above description, the amount of data to be written to the header block 33 is desirably the minimum necessary. Then, the number of times of turning off the power of the camera 10 for one memory card 11 can be effectively increased. Update of the header block 33 will be described later in detail.

The header information pointer 36 is an empty / busy display area for designating a header block in which the latest header information is written among a plurality of header blocks 33 in the header block area 34. In this embodiment, the header information pointer 36 is
A 192 byte storage area is used, and the bit position of the binary “0” located 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. Refers to block 33. In the example shown,
Since it is 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 the latest header information is carried.
Of course, in order to display the empty state of the header block 33 or the latest recording state or the recording order, other methods such as providing display bits in each header block 33 may be used instead of taking such a pointer form. .

As described above, in the initialization for erasing all the recording information in the storage area 60, all the recording 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 to the header block # 0. After that, every time the power is turned off, the updated header information
It is written in order of 1, # 2, # 3. In response 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, from the head each time. Therefore, the first bit “0” as viewed from the left in 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 bit is set to "1" at initialization.
Although the OM is used, if the value is "0" at the time of initialization, the bit value of the header information pointer 36 is reversed, and the rightmost "1" indicates the number of the latest header block 33. .

A memory card 11 is mounted on a camera 10,
When the power of the camera 10 is turned on, the system controller 13 of the camera 10 outputs a read command of the header 28 from the storage area 60 of the memory card 11 in response thereto. 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
Responds to this, reads out the header information of the header block 33 corresponding to the rightmost bit “0” of the header information pointer 36 and outputs it 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 updates this header information in the memory 14 every time an image is taken. Along with this, the system controller 13
Outputs the image data of one frame, that is, one packet, the address of the cluster to be stored, and their accompanying information. The memory controller 40 receives the data via the interface 45, temporarily stores the image data and management information in the buffer memory 50, reads out the data from the buffer memory 50, and reads out the image data and the management information according to the designated address.
The directory data is written in 24, the MAT data in the MAT area 26, and the image data in the other cluster areas.

When the photographing is completed and the user performs an operation of turning off the power, the system controller 13 of the camera 10 reads the header information from the memory 14 and outputs this to the memory card 11 through the card interface 16. When the memory controller 40 receives this, the memory controller 40
Accumulate in 50 once. Thereafter, the header information pointer 36 is examined, and the header information is read out from the buffer memory 50 and written into the first, that is, the header block 33 corresponding to the leftmost bit “1”. At the same time, the memory controller 40 inverts the leftmost, that is, the first bit “1” of the header information pointer 36 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 into 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 a new header block 33. However, the configuration may be such that a new header block 33 is written after a predetermined number of times of shooting, for example, each time shooting is performed.

FIG. 5 shows another embodiment of the present invention. In the embodiment shown in FIG. 1, the area where the header information is stored is limited to the specific cluster # 1. However, in this method, in the case of a memory card using an EEPROM with a large storage capacity,
The number of updates of the header information increases, and thus the capacity of the area 28 usable as the header area may be insufficient. The embodiment shown in FIG. 5 solves this problem. A header area 28 in which header information is to be written is formed in an arbitrary cluster 21, and a cluster in which this header area 28 is recorded in a specific cluster, for example, cluster # 1. An area 81 in which the number 21 is written is provided, and the intended header area 28 can be accessed by additionally writing the area 81 in an updated manner.
More specifically, in the cluster number area 81, the number of the cluster 21 in which the header area 28 is formed is written, and a cluster number area indicating the cluster 21 including the latest header area 28
81 is indicated by the pointer 82. That is, the cluster number area 81 is additionally written in the same manner as 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 the cluster address.

When the power of the camera 10 is turned on, a specific area 80 is first accessed, and the latest cluster 21 number of the header area 28 is searched by the pointer 82 and the cluster number area 81. The information of the latest header block 33 from the latest header area 28 is taken 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 writing header information to the header area 28, the latest header area 28 is similarly accessed, and the header information is written to an unused block 33 with reference to the pointer 36. In this method, when information cannot be written to a new header block 33 in one cluster 21, the header area 28 can be used extensively by setting the header area 28 in another cluster 33.

[0025]

As described above, according to the present invention, even in a memory card using an EEPROM of a batch erasing method or a block erasing method, header data with a large number of rewrites 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, an EEPROM or EPROM memory card having format compatibility, usable like an SRAM card, and consuming less power than an SRAM card can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a storage area of management data in the embodiment shown in FIG. 2;

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

FIG. 3 is a diagram illustrating an example of a configuration of a storage area in the embodiment illustrated in FIG. 2;

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 of 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)

(57) [Claims] 1. A storage management method 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 the memory,
In the method, header information provided in the storage area and including at least a part of management information related to storage of image information is additionally provided.
A plurality of header recording area recorded in, provided in the storage area, and an empty busy display means for displaying the empty busy for each header recording area of the plurality of writes the image information in the storage area, first At the point of time, the header information relating to the image information is written into the empty header recording area indicated by the empty / occupied display means of the plurality of header recording areas, and the display corresponding to the written header recording area in the empty / occupied display means is performed. And a control means for closing and displaying the memory card. 2. The method according to claim 1, wherein said control means has a storage means for storing the header information in a rewritable manner, and said control means operates at 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 based on the empty / occupied display means and stored in the storage means, and the header information stored in the storage means is read out. The memory management method of a memory card, wherein the memory card is constantly updated. 3. A storage management method for a memory card having a storage area of an EEPROM in which a record is erased to a predetermined logical state during initialization and information is additionally written to the memory,
The method includes: a header recording area provided in the storage area and recording header information including at least a part of management information related to storage of image information; and a storage position in the storage area where the header recording area is formed. A plurality of storage location indication areas for additionally indicating, and an indication means provided in the storage area, for indicating an area of the plurality of storage location indication areas to which the latest instruction has been added; and At the first point in time, the storage means refers to the area of the plurality of storage location indication areas to which the latest instruction has been added based on the indication means, and designates the storage location indication area of the referenced storage location indication area. Control means for deriving a position in an area and writing header information relating to the image information in the header recording area at the derived position. Storage management method. 4. The method according to claim 3, wherein the header recording area comprises: a first plurality of recording areas in which the header information is respectively recorded; A second recording area to be displayed, wherein at a first point in time, the control means stores header information relating to the image information in an empty recording area indicated by a second recording area of the first plurality of recording areas. A storage management method for a memory card, wherein a display in a written and second recording area corresponding to the written first recording area is closed and displayed. 5. The method according to claim 4, wherein said control means has storage means for rewritably accumulating said header information, and said control means operates at a second time point different from the first time point. so,
On the basis of the instruction of the instruction 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 and stored in the storage means, A storage management method for a memory card, wherein header information stored in a storage means is constantly updated.