JP2006139550A - Recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium having a storage means divided into a plurality of storage areas, and allowing a changeover of the storage area by a time interval wherein electricity carrying to the recording medium is cut off, so as to use the large-capacity recording medium in a conventional recording/reproducing device. <P>SOLUTION: This readable/writable recording medium 100 connected to the external recording/reproducing device for use has: the storage means 160 having the plurality of storage areas; a controller 120 controlling the storage means 160 on the basis of an instruction of the recording/reproducing device; an active area designation register 140 designating an active area from the plurality of storage areas; and an active area changeover means 150 changing over the active area when a time wherein the electricity carrying to the recording medium is cut off is a preset threshold value or below. In the recording medium 100, the changeover of the storage area can be controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording medium capable of switching a plurality of storage areas.

  A recording / playback apparatus such as a digital camera or a mobile phone uses a memory card using a flash memory represented by a CompactFlash (registered trademark) or SD (Secure Digital) card as a recording medium. In recent years, with the progress of semiconductor technology and mounting technology, the capacity of a memory card is about to exceed 2 gigabytes. There has also been proposed a device that virtually shows a magnetic disk device having a capacity of several tens of gigabytes as a memory card (see, for example, Patent Document 1).

  On the other hand, many conventional recording / playback apparatuses manage still image files, moving image files, and the like in a recording medium using FAT16 (File Allocation Table 16) which is a typical file system. However, the FAT 16 is a file system whose address for managing a cluster is 16 bits. If the cluster size is 32 kilobytes, the capacity that can be managed by the FAT16 file system is only 2 gigabytes at maximum. Therefore, in a conventional FAT16 recording / reproducing apparatus, when a recording medium having a capacity exceeding 2 gigabytes is used, there is a problem that an area exceeding 2 gigabytes cannot be easily handled.

In response to this problem, the conventional memory card and the storage area switching method include a mechanical switch in a memory card having a plurality of storage areas so that one of the plurality of storage areas can be selected. (For example, refer to Patent Document 2).
JP 2004-213487 A JP 2004-86503 A

  In the conventional configuration, a new mechanical switch has to be added to select one from a plurality of storage areas.

  However, the shape of the memory card is determined by the standard. For example, in the case of an SD card, the external dimensions are 24.0 mm (W) × 32.0 mm (L) × 2.1 mm (T) according to the SD memory card standard, and the position of the write protect switch is also determined. Yes. In order to add a new mechanical switch, there is a problem that a new standard has to be formulated.

  In addition, in order to change the shape of the memory card, it is necessary to change the mold for producing the memory card, so that there is a problem that the manufacturing cost becomes expensive.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a recording medium capable of selecting one of a plurality of storage areas without changing the shape defined by the standard. And

  In order to solve the above-described conventional problems, the recording medium of the present invention is a readable / writable recording medium used by connecting to an external recording / reproducing apparatus, an interface connected to the recording / reproducing apparatus, and a plurality of storage areas A storage unit having a characteristic value unique to the recording medium, a controller for controlling the storage unit based on an instruction from the recording / playback apparatus and a value of the internal register, and a plurality of storage areas And an active area switching means for switching the active area with reference to the time when the power supply to the recording medium is cut off.

  Further, in the recording medium, the active area switching means has charge storage means for storing charges, and measures the amount of charge stored in the charge storage means when the recording medium is connected to the recording / reproducing apparatus. The active region is switched by comparing the value with a predetermined threshold value.

  Further, in the recording medium, the active area switching means switches the active area when the time when the power supply to the recording medium is cut off is equal to or less than a predetermined threshold value.

  Further, in the recording medium, an elapsed time from when the recording medium is removed from the recording / reproducing apparatus until it is inserted again is used as the time when the energization is cut off.

  Furthermore, in the recording medium, as the time when the energization is cut off, an elapsed time from when the power of the recording / reproducing apparatus is turned off to when it is turned on again is used.

  Further, in the recording medium, the controller includes an active area capacity calculating unit that calculates an active area capacity from the active area specifying register, and an internal register conversion that converts the internal register based on a calculation result of the active area capacity calculating unit. Means.

  Further, in the recording medium, the controller includes an offset calculating unit that calculates an offset of the address from the active area designation register, and an adder that adds the calculation result of the offset calculating unit and the address transmitted from the recording / reproducing apparatus. It is characterized by including.

  Further, the recording medium further comprises display means for recognizing the storage area designated by the active area designation register from the outside.

  Further, the recording medium further comprises display means for recognizing from the outside that the storage area designated by the active area designation register has been switched.

  According to the recording medium of the present invention, one of a plurality of storage areas in the recording medium can be selected without changing the shape defined by the standard.

  Hereinafter, embodiments of the recording medium of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a block diagram of a recording medium in the first embodiment of the present invention. In FIG. 1, the recording medium 100 is assumed to be an SD memory card.

  In the SD memory card, the interface 110 includes a plurality of terminals and an interface driver 200 as shown in FIG. FIG. 2 is a diagram showing details of the interface 110 in the first embodiment of the present invention. There are a total of nine terminals, which are connected to an external recording / reproducing apparatus (not shown). The recording medium 100 is supplied with power from the recording / reproducing apparatus through the terminal VDD, the terminal VSS1, and the terminal VSS2. Further, the terminal CMD (command or response) synchronized with the terminal CLK (clock signal) and the terminal DAT0, the terminal DAT1, the terminal DAT2, and the terminal DAT3 (data) are transmitted and received. The interface driver 200 fetches commands and data from the terminals and outputs responses and data to the terminals according to the SD memory card standard. The terminal CD also used as the terminal DAT3 is used for detecting whether or not the card is connected to the recording / reproducing apparatus.

  The internal register 130 includes a plurality of registers according to the SD memory card standard. Each register is read by a command from the recording / reproducing apparatus, and affects the operation of the recording / reproducing apparatus. For example, the operating power supply voltage of the card, each specification value of the card, and the like are recorded. There is also a register in which the maximum number of bytes in the active area described later is recorded, and the recording / reproducing apparatus recognizes this value as the storage capacity of the card.

  The storage means 160 is composed of one or more storage areas. FIG. 3 is a diagram showing the configuration of the storage means 160 in the first embodiment of the present invention. FIG. 3 shows an example in which the storage unit 160 having a capacity of 8 GB is configured by four storage areas (first storage area 161 to fourth storage area 164) having a capacity of 2 GB. Each storage area is formatted into a FAT16 file system by the recording / reproducing apparatus, and a master boot record / partition table, a partition boot sector, file allocation tables 1 and 2, a root directory, and a data area are written therein. The storage unit 160 can read data by designating an address or write data by designating an address and data.

  The active area designation register 140 designates an active area from among a plurality of storage areas. The active area is an area recognized by the recording / reproducing apparatus. The active area designation register 140 is a set of 1-bit flags expressing whether each storage area is active. The flag corresponding to each storage area means that the storage area is an active area when it is 1, and means that the storage area is inactive when it is 0. Since this flag exists for the number of bits corresponding to the number of storage areas, the number of bits of the active area designation register 140 also becomes the number of bits corresponding to the number of storage areas. For example, when the storage unit 160 is composed of four storage areas as shown in FIG. 3, the active area designation register 140 is a 4-bit register.

  FIG. 4 is a diagram showing storage area switching and the value of the active area designation register 140 in the first embodiment of the present invention. In FIG. 4, the storage area drawn with a dotted line indicates an inactive area. FIG. 4A shows a state in which the first storage area 161 is active. At this time, the value of the active area designation register 140 is 0001b (hereinafter, the last b represents a binary number). is there. That is, bit 0 (the least significant bit is bit 0) of the active area designation register 140 corresponding to the first storage area 161 is 1. Similarly, FIG. 4B shows the second storage area 162, FIG. 4C shows the third storage area 163, and FIG. 4D shows the fourth storage area 164 active. The values of the designation register 140 are 0010b, 0100b, and 1000b, respectively. FIG. 4E shows that the value of the active area designation register 140 is 1111b and all the storage areas are active areas. In this case, the entire storage unit 160 is recognized by the recording / reproducing apparatus as one storage area. When the recording / reproducing apparatus can use a file system corresponding to a large capacity (for example, FAT32 file system instead of FAT16 file system), the recording / reproducing apparatus can access the recording medium 100 as an 8 GB large capacity SD memory card. Note that this function (a function of using the entire storage unit 160 as one storage area) is an option and may not be implemented.

  The active area switching means 150 switches the active area on the basis of the time when the energization to the recording medium is interrupted (hereinafter referred to as the interruption time). FIG. 5 shows a block diagram of the active area switching means 150 in the first embodiment of the present invention. In FIG. 5, VDD 620 is a drain voltage, and is connected to the terminal VDD in FIG. VSS650 is a source voltage and is connected to the terminal VSS1 and the terminal VSS2 in FIG. The resistor 630 has a resistance value R, and the capacitor 640 has a capacitance C. The operational amplifier 600 operates as a voltage follower, and uses the input voltage VDD 620 as an output voltage as it is. The operational amplifier 600 separates the voltage converted to the A / D converter 610 and the voltage supplied to the active area designation register updating unit 680. The voltage supplied to the active area designation register updating means 680 also serves as a power source for the controller of the recording medium and the internal register.

  In the active region switching means 150, whether or not the cutoff time has exceeded a predetermined threshold (hereinafter referred to as a switching limit time T) has been measured by a measured value AD 660, which is a voltage value converted to the A / D converter 610. judge. That is, when the measured value AD660 is equal to or higher than the switching voltage TV670, it is assumed that the cutoff time is equal to or shorter than the switching limit time T. However, the switching voltage TV670 is determined in advance based on the switching time limit T. A method for determining the switching voltage TV670 will be described later.

  The active area designation register updating unit 680 compares the measurement value AD660 with the switching voltage TV670 and obtains the value REG690 of the active area designation register 140. FIG. 7 is a diagram showing a first detailed flow of the active area designation register updating means 680 in the first embodiment of the present invention. The operation of the active area designation register updating means 680 starts from step 720 for calculating a difference between the measured value AD660 and the switching voltage TV670 after a certain time lag after energization. When the value of the measured value AD660 is equal to or lower than the switching voltage TV670, it is determined that the cutoff time has passed the switching limit time T, and the active region is not switched. On the contrary, when the value of the measured value AD660 is equal to or higher than the switching voltage TV670, it is determined that the cutoff time is equal to or shorter than the switching limit time T, and the process proceeds to step 730 for switching the active region. Step 730 of switching the active area is processed by more detailed steps 740-770. First, step 740 is executed in which the value REG of the current active area designation register 140 is shifted to the left by 1 bit and stored in REG. Next, step 750 in which the logical product of the REG and 1111b is stored in REG is executed. Here, 1111b logically ANDed with REG is an example in the case where the storage unit 160 is composed of four storage areas as shown in FIG. 4, and is determined by the number of bits corresponding to the number of storage areas. In step 760 in which it is determined whether or not REG as a result of step 750 is 0. If REG is other than 0, the entire process is terminated. That is, it is the case of (a) → (b), (b) → (c), (c) → (d) in FIG. 4, and the REG values are 0001b → 0010b, 0010b → 0100b, 0100b → 1000b. This is the case when it changes. In step 760, if REG is 0, step 770 is executed in which REG is set to 0001b, and the entire process is terminated. That is, it is the case of (d) → (a) in FIG. 4, and the value of REG changes from 1000b → 0001b. The switching of the active area shown in FIG. 7 shows a flow in the case where the option in which the value of the active area specifying register 140 is 1111b, that is, the option in which all the storage areas are active areas is not implemented.

  FIG. 8 is a diagram showing a second detailed flow of the active area designation register updating means 680 in the first embodiment of the present invention. FIG. 8 is a flow for implementing the option. In this case, step 780 is executed instead of step 730 for switching the active area. In step 780, first, step 790 for determining whether or not the value of REG is 1111b is executed. If REG is 1111b, step 770 in which REG is set to 0001b is executed, and the entire process is terminated. That is, it is the case of (e) → (a) in FIG. 4, and the value of REG changes from 1111b → 0001b. If REG is other than 1111b, Steps 740 and 750 are executed, as in Step 730 of FIG. 7, by shifting REG left by 1 bit, performing logical AND with 1111b, and storing it in REG. Then, in step 760 for determining whether or not REG as a result of step 750 is 0, if REG is other than 0, the entire process is terminated as in FIG. In step 760, when REG is 0, step 795 which sets REG to 1111b is executed, and the whole processing is ended. That is, it is the case of (d) → (e) in FIG. 4, and the value of REG changes from 1000b → 1111b.

  As described above, the active area switching unit 150 calculates the value of REG 690 and rewrites the value of the active area designation register 140. Note that the value of the active area designation register 140 in the initial state (at the time of factory shipment) is 0001b.

  Hereinafter, a method for determining the switching voltage TV670 will be described with reference to FIG. FIG. 6 is a diagram showing an input voltage waveform to the A / D converter in the first embodiment of the present invention. FIG. 6A shows time on the horizontal axis and the input voltage to the A / D converter 610 on the vertical axis, and shows the response waveform when the power supply is cut off at the points in the figure. In other words, the voltage during energization is maintained at VDD, but when the power is turned off, it gradually becomes 0V. At this time, the input voltage ADIN to the A / D converter 610 is calculated according to the following equation.

ただし、ｔは電源遮断からの経過時間とする（すなわち、遮断時がｔ＝０）。また、ｅｘｐ（）は指数関数を示す。

However, t is an elapsed time since the power is shut off (that is, t = 0 when the power is shut off). Exp () represents an exponential function.

  FIG. 6B shows a response waveform of the input voltage to the A / D converter 610 when the power is turned off and the power is turned on again after the interruption time in the figure has elapsed. The input voltage to the A / D converter 610 gradually increases and stabilizes at VDD. At this time, ADIN is calculated according to the following equation.

ただし、ｔは通電からの経過時間とする（すなわち、通電時がｔ＝０）。なお、その他の記号の意味は、前記記載のものと同じである。

However, t is the elapsed time from energization (that is, t = 0 when energization). The meanings of other symbols are the same as those described above.

  FIG. 6C shows the response waveform of the input voltage to the A / D converter 610 when the power is turned off and the power is turned on again after the interruption time in the figure, as in FIG. 6B. The blocking time is shorter than that in FIG. That is, FIG. 6B shows a case where the cutoff time is longer than the switching limit time T, and FIG. 6C shows a case where the cutoff time is shorter than the switching limit time T.

  In the active region switching means 150, after energization, after a certain time lag TM, the A / D converter 610 converts the input voltage to obtain the measured value AD660. Therefore, the switching voltage TV670 is determined so that the measured value AD660 is equal to or lower than the switching voltage TV670 when the cutoff time is longer than the switching limit time T, and the measured value AD660 is equal to or higher than the switching voltage TV670 when it is shorter. The time lag TM is a time during which the active area switching unit 150 is reset until the power supply voltage supplied from the recording / reproducing apparatus rises.

  The controller 120 is means for communicating with the recording / reproducing apparatus in accordance with the SD memory card standard. FIG. 9 shows a block diagram of the controller 120 in the first embodiment of the present invention. The controller 120 interprets the command 800 and data 820 received from the recording / reproducing apparatus via the interface 110 by the command decoder 830 and transmits a response 810 and data 820 to the recording / reproducing apparatus via the interface 110. Based on the command 800, the controller 120 writes the data 820 from the recording / reproducing apparatus in the storage unit 160 and reads the data 820 to the recording / reproducing apparatus. Further, the value of the internal register 130 is read as data 820 to the recording / reproducing apparatus.

  Hereinafter, operations different from the SD memory card standard in the controller 120 will be described. The first operation is an operation of adding an offset to the address to the storage means 160 according to the value of the active area designation register 140. The second operation is an operation of converting the data read from the internal register 130 according to the value of the active area designation register 140.

  In the first operation, the storage / reproduction device accesses (reads or writes) the storage unit 160. The command 800 and data 820 are input from the interface 110 to the command decoder 830. When the command 800 is an access to the storage unit 160, the command decoder 830 operates the address acquisition unit 860 to acquire the data 820 as the logical address 870. Further, the offset calculation means 840 is operated to calculate the offset 850 based on the active area designation register 140 (details of the calculation method will be described later). Further, the logical address 870 and the offset 850 are added together by an adder 880 to be converted into a physical address 890. The controller 120 reads data 820 from the storage unit 160 and writes data 820 by the physical address 890.

  The offset 850 is calculated based on the active area designation register 140 so that the head address of the current active area becomes the logical address 0. That is, among the bits having the value of the active area designation register 140 of 1, the lowest bit is bit N (the least significant bit is 0), and the number of blocks in each storage area is B, N × B. Can be calculated. However, the block number B is determined in advance depending on the capacity of each storage area and the number of bytes for each cluster. For example, if each storage area is 2 GB and the number of sectors per cluster is 32 KB, B = 2 GB / 32 KB = 65536. At this time, if the value of the active area designation register 140 is 0100b, the offset 850 is 2 × 65536 = 0x20000 (hexadecimal number). Note that the value of the active area designation register 140 is not updated unless the power is turned off. Therefore, the offset 850 value calculated once can be saved and reused.

  In the second operation, the storage / reproduction device reads a value from the internal register 130. The command 800 and data 820 are input from the interface 110 to the command decoder 830. When the command 800 is a read from the internal register 130, the command decoder 830 operates the active area capacity calculation unit 900 to calculate the maximum number of bytes 910 of the active area based on the active area designation register 140, and sets the internal register 130. The internal register conversion means 920 performs conversion. The active area capacity calculation means 900 calculates the maximum number of bytes 910 as M × D, where M is the number of bits whose active area designation register 140 is 1 and D is the capacity of each storage area. If the value of the active area designation register 140 is 0010b and D = 2 GB, the maximum number of bytes 910 is 1 × 2 GB = 2 GB. The internal register conversion means 920 converts only the register in which the maximum number of bytes in the active area is recorded among the internal registers 130. The maximum number of bytes 910 is read as data 820 in the same format as the internal register 130 in accordance with the SD memory card standard. Other registers are not converted, and the read value of the internal register 130 is read as data 820 as it is. Note that the value of the active area designation register 140 is not updated unless the power is turned off. Therefore, the value of the maximum number of bytes 910 calculated once can be stored and reused.

  The operation of the recording medium configured as described above when connected to the recording / reproducing apparatus will be described below. A method for switching storage areas will also be described.

  First, the user of the recording / reproducing apparatus inserts the recording medium of the present invention into the recording / reproducing apparatus and turns on the power of the recording / reproducing apparatus. The recording / reproducing apparatus reads each specification of the recording medium from the recording medium in the initialization procedure. Each specification of the recording medium is stored in an internal register of the recording medium and affects the operation of the recording / reproducing apparatus. Further, the file format (file system) recorded in the recording apparatus also affects the operation of the recording / reproducing apparatus.

  When the recording medium has been formatted, the recording / reproducing apparatus reads the format information of the recording medium from address 0 of the logical address and tries to access the recording medium. At this time, as described in the first operation of the controller 120, the recording medium of the present invention adds the offset calculated by the offset calculation means 840 to the logical address to convert it into a physical address, and accesses the storage means. . That is, the recording / reproducing apparatus accesses the recording medium so that the active area of the recording medium is at logical address 0 without recognizing that there are a plurality of storage areas.

  When the recording medium is unformatted, the recording / reproducing apparatus reads the maximum number of bytes from the internal register of the recording medium and attempts to format the recording medium with a file system that can be handled by the recording / reproducing apparatus. At this time, as described in the second operation of the controller 120, the recording medium of the present invention uses the maximum number of bytes calculated by the active area capacity calculation unit 900 instead of the maximum number of bytes stored in the internal register. To the recording / reproducing apparatus. That is, the recording / reproducing apparatus formats the recording medium on the assumption that the recording medium has only the storage capacity for the active area without recognizing the actual storage capacity of the storage medium.

  Next, the user of the recording / reproducing apparatus stores various data on the recording medium using the function of the recording / reproducing apparatus. For example, it may be still image data of a digital camera or music data of an audio player. As usage by the user proceeds, the remaining capacity of the storage medium gradually decreases, and the user finally considers replacing the recording medium. At this time, in the recording medium of the present invention, the user can switch the active area by inserting and removing the recording medium. Alternatively, the active area can be switched by turning on / off the power of the recording / reproducing apparatus.

  As described above, in the first embodiment of the present invention, the active area can be switched based on the time when the power supply to the recording medium is cut off by providing the active area designation register and the active area switching means. The active area can be designated from a plurality of storage areas.

  In the first embodiment of the present invention, the storage area can be handled as a recording medium having a capacity corresponding to the recording / reproducing apparatus by making the storage areas have different capacities for each storage area.

  In the first embodiment of the present invention, an SD memory card is assumed as a recording medium. However, a compact flash (registered trademark) or a memory stick (registered trademark) may be used.

  The present invention aims to provide a recording medium that can select one of a plurality of storage areas without changing the shape defined by the standard. For this reason, the currently active storage area may be displayed. A specific example will be described with reference to FIG. FIG. 10 shows the appearance of the recording medium in the first embodiment of the present invention. In FIG. 10, a plurality of LEDs 950 are provided on the back surface of the recording medium. The LED 950 is turned on when it is 1 and turned off when it is 0, corresponding to the value of each bit of the active area designation register. Thereby, even when the recording medium is connected to the recording / reproducing apparatus and used, the user can identify the active recording area. However, the number of LEDs provided and the lighting method of the LEDs are not limited to the above example.

  Further, a means for transmitting to the user that the active storage area has been switched may be provided. For example, a means for transmitting a sound source with a sound inside the recording medium or having an LED as shown in FIG.

  The recording medium according to the present invention has an active area switching means, and can select one of a plurality of storage areas in the recording medium. When handling a large capacity recording medium in the recording / reproducing apparatus, Useful. In particular, it can be suitably used for a memory card connected to a recording / reproducing apparatus such as a digital camera.

1 is a block diagram of a recording medium in a first embodiment of the present invention. The figure which shows the detail of the interface in 1st Example of this invention The figure which shows the structure of the memory | storage means in 1st Example of this invention. The figure which shows the value of the switching of a storage area and the active area designation | designated register in 1st Example of this invention Block diagram of active area switching means in the first embodiment of the present invention The figure which shows the input voltage waveform to the A / D converter in 1st Example of this invention The figure which shows the 1st detailed flow of the active area designation | designated register update means in 1st Example of this invention. The figure which shows the 2nd detailed flow of the active area designation register update means in 1st Example of this invention. Block diagram of the controller in the first embodiment of the present invention 1 is an external view of a recording medium according to a first embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Recording medium 110 Interface 120 Controller 130 Internal register 140 Active area designation register 150 Active area switching means 160 Storage means 161 First storage area 162 Second storage area 163 Third storage area 164 Fourth storage area 200 Interface driver 600 operational amplifier 610 A / D converter 620 VDD
630 Resistor 640 Capacitor 650 VSS
660 measured value AD
670 Switching voltage TV
680 Active area designation register update means 690 REG
800 Command 810 Response 820 Data 830 Command decoder 840 Offset calculation means 850 Offset 860 Address acquisition means 870 Logical address 880 Adder 890 Physical address 900 Active area capacity calculation means 910 Maximum number of bytes 920 Internal register conversion means 950 LED

Claims (9)

In a readable / writable recording medium used by connecting to an external recording / reproducing device,
An interface connected to the recording / reproducing apparatus;
Storage means having a plurality of storage areas;
An internal register that holds characteristic values specific to the recording medium;
A controller for controlling the storage means based on an instruction of the recording / reproducing apparatus or a value of the internal register;
An active area designation register for designating an active area from the plurality of storage areas;
A recording medium comprising active area switching means for switching the active area on the basis of a time when power to the recording medium is cut off. The active area switching means includes
Having charge storage means for storing charge,
When the recording medium is connected to the recording / reproducing apparatus, the active area is switched by comparing a value obtained by measuring a charge amount accumulated in the charge accumulating unit with a predetermined threshold value. The recording medium according to claim 1. The active area switching means includes
The recording medium according to claim 2, wherein the active area is switched when a time when the power supply to the recording medium is cut off is equal to or less than a predetermined threshold value. As the time when the energization was cut off,
4. The recording medium according to claim 3, wherein an elapsed time from when the recording / reproducing apparatus is removed to when the recording / reproducing apparatus is inserted again is used. As the time when the energization was cut off,
4. The recording medium according to claim 3, wherein an elapsed time from when the power of the recording / reproducing apparatus is turned off to when it is turned on again is used. The controller is
Active area capacity calculating means for calculating the capacity of the active area from the active area designation register;
The recording medium according to claim 1, further comprising an internal register conversion unit that converts the internal register based on a calculation result of the active area capacity calculation unit. The controller is
Offset calculating means for calculating an offset of an address from the active area designation register;
The recording medium according to claim 1, further comprising: an adder that adds a calculation result of the offset calculation means and an address transmitted from the recording / reproducing apparatus. 2. The recording medium according to claim 1, further comprising display means for recognizing a storage area designated by the active area designation register from the outside. 2. The recording medium according to claim 1, further comprising display means for recognizing from the outside that the storage area designated by the active area designation register has been switched.

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