JP2010225011A - Information terminal and access method for removable storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve response to an access request to a removable storage medium. <P>SOLUTION: The information terminal having a removable storage medium includes: a processing part receiving an access request with the storage medium mounted thereon, and accessing the storage medium; an information management part storing control information read from the storage medium; and a detection part detecting dismounting of the storage medium. The processing part responds to the access request without reading the control information from the storage medium based on the control information acquired from the information management part when the dismounting is not detected after the preceding access, or reads the control information from the storage medium to respond to the access request, when dismounting is detected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an information terminal to which a removable storage medium can be attached and a method for accessing the removable storage medium.

  Many portable information terminals such as mobile phones and PDAs (Personal Digital Assistance) are configured to be able to use memory cards. For example, a memory card is used for recording photographing data by a built-in camera. In addition, in an information terminal having a function of reproducing music and video, a user can use the information terminal as a player by attaching a memory card in which content is recorded. If the memory card is replaced, other contents can be played. An information terminal equipped with a memory card can hold a large amount of data that cannot be stored in the built-in memory.

  On the other hand, there is a technology that uses a memory card as an ID card that identifies a user of the information processing apparatus with respect to the use of the memory card. A user of an information processing apparatus to which this technology is applied must attach an ID card when using it. When the ID card is removed in a power saving state in which the CPU stops operating, the power source of the volatile storage device that is a work area for executing the program is shut off for the purpose of enhancing security (Patent Document 1).

JP 2001-75666 A

  When accessing a memory card that is a removable storage medium, control information is read from the memory card each time, and an access point is set based on the read control information. The control information is information indicating the position of the file, and is stored in a specific area of the memory card. The size of the control information is larger as the storage capacity of the memory card is larger. That is, as the capacity of the memory card increases, the time for reading the control information becomes longer. For this reason, for example, there may be a delay in the reproduction of music content. In the reproduction of music content, intermittent access is performed in which a certain amount of time of about several tens of seconds is read and reproduced, and the next certain amount of time is read before the reproduction ends. At this time, if it takes too long to read the control information, the reproduction is interrupted.

  In view of such circumstances, an object of the present invention is to speed up a response to an access request to a removable storage medium.

  An information terminal that achieves the above object is an information terminal in which a storage medium can be attached and detached, a processing unit that receives an access request in a state in which the storage medium is mounted, and accesses the mounted storage medium; An information management unit that stores control information read from the storage medium; and a detection unit that detects removal of the storage medium. The processing unit does not read the control information from the storage medium based on the control information acquired from the information management unit when the detection unit has not detected removal since the previous access. In response to the access request, when removal is detected by the detection unit, the control information is read from the storage medium to respond to the access request.

In a preferred aspect, the information terminal further changes the mode of power supply to the mounted storage medium from the normal mode that is the mode at the time of access when a fixed time has passed without access from the end of access by the processing unit. A method for achieving the above-described object is provided with a power control unit that switches to a power saving mode. The method is an access method for a removable storage medium that is accessed in a state where the apparatus is mounted on the apparatus, and the control information read from the removable storage medium If the removal of the removable storage medium is detected and no removal is detected, the control information is read from the removable storage medium based on the stored control information. If the removable storage medium is accessed without The control information is read from the bubble storage medium, and the removable storage medium is accessed based on the read control information.

  While the storage medium continues to be loaded, reading of the control information from the storage medium is omitted when the control information is stored in a plurality of intermittent accesses. As a result, the requested data can be read or written earlier by the time required for reading the control information.

  When removal of the storage medium is detected, the control information is read and data is read or written, so even if the recording medium is different before and after removal, the newly installed recording medium Data can be read or written as required.

  By controlling the power supply for access, power consumption can be reduced. In particular, in a portable information terminal driven by a battery, control for saving power is important.

According to the present invention, a response to an access request to a removable storage medium can be speeded up.

It is a figure which shows the example of the access form and power control of the memory card based on embodiment of this invention. It is a figure which shows the hardware constitutions of a mobile telephone. It is a figure which shows the structure of FAT information. It is a figure which shows the function structure of the principal part of a mobile telephone. It is a flowchart which shows the outline | summary of the operation | movement relevant to the access of a memory card.

  Take a mobile phone as an example. In mobile phones, a memory card represented by an SD card is generally used as a removable storage medium (detachable storage medium). However, the access method for a removable storage medium described below can be applied to any device or apparatus that can use a memory card or other removable storage medium.

  FIG. 1 shows the characteristics of the operation of the mobile phone according to the present embodiment. There are two types of access to the memory card: one that reads later-described FAT information, which is control information, from one that does not read from the memory card. In the first access for reading FAT information, data specified by an access request is read or written after the FAT information is read. On the other hand, the second access which does not read FAT information starts from reading or writing of data. That is, the second access can respond to the access request almost earlier than the first access by the time T1 required for reading the FAT information.

  The required time T1 for reading FAT information is longer than the required time for reading or writing average data. For example, when the access speed of the memory card is about 5 Mbytes / second, the required time for reading 1 Mbytes of data is 0.2 seconds, whereas the required time T1 for a memory card with a capacity of 4 Gbytes is 0. 75 seconds (measured by an analyzer). Since the required time T1 depends on the capacity of the memory card, the required time T1 in a large-capacity memory card is longer. For example, the required time T1 for a memory card with a capacity of 8 GB is 2.04 seconds.

  In order to omit reading of the FAT information, the presence / absence of removal of the memory card from the mobile phone is detected. Further, FAT information read from the memory card in the first access is stored. If there is no removal, it is only necessary to use the previously read FAT information, so there is no need to read the FAT information from the memory card again. If it is removed, there is a possibility that the memory card has been replaced, so it is necessary to read the FAT information again. In this case, the second access may be performed. As long as the memory card continues to be attached, if the first access is performed only once, the access request can be correctly responded even if the second access in which reading of the FAT information is omitted is performed thereafter.

  In addition, as shown in FIG. 1, in this embodiment, the power supplied to the memory card is controlled. A memory card is a device that does not require power supply for data retention, but can be read and written while power of a predetermined voltage is supplied. The power supply mode is set to the normal mode (the mode at the time of access) during access and until a set time (for example, 2 seconds) elapses from the end of access, and power that enables access is supplied. The period from the end of access until the next access request is received is set to the power saving mode, and the supplied power is reduced compared to the normal mode. For example, the current is suppressed.

  The reduction of the power supply in the non-access period of intermittent access contributes to making a battery-operated mobile phone operable for as long as possible. For example, in the reproduction of music content in which a song is 3 minutes or 5 minutes, an access request is issued at intervals of several tens of seconds depending on the size of a buffer for temporarily storing reproduction data. Assuming that it takes 1 second to read out data, about several seconds together with the waiting time for shifting to the power saving mode (for example, 2 seconds) is the time for the energization mode in the second access. Compared to this time, the access interval of several tens of seconds is significantly longer. That is, as a whole, the ratio of the power saving mode is larger than that of the normal mode.

  Hereinafter, the configuration of the mobile phone will be described in detail.

  As shown in FIG. 2, the mobile phone 1 includes a CPU 10, a ROM 11, a RAM 12, an audio circuit 13, a card device 15, and another circuit 20.

  The CPU 10 mainly controls operations related to the memory card 2. The CPU 10 executes a control program stored in the ROM 11. At that time, the RAM 12 is used as a work area. The RAM 12 stores the detection result of whether or not the memory card 2 is removed and the FAT information read from the memory card 2.

  The audio circuit 13 drives the speaker 14 during a call and reproduction of music content. The audio circuit 13 has an earphone connection section, and drives the earphone when the earphone is connected.

  The card device 15 includes a storage unit 16 in which the memory card 2 is inserted in a slide insertion format, a power supply circuit 18 for accessing the memory card 2, and a card removal unit that outputs a predetermined signal when the memory card 2 is removed. A detection circuit 19 is provided.

  The storage unit 16 includes a connector that engages with a terminal of the memory card 2 and an ejection mechanism. The eject mechanism pushes out the memory card 2 so that the user can grasp and pull it out when the user pushes the memory card 2 in the mounted state into the storage unit 16.

  The card removal detection circuit 19 has a switch that operates when the user pushes the memory card 2 in the loaded state into the storage unit 16. The switch is connected to the power supply circuit 18, and the voltage between the terminals of the switch is changed by operation. This change is captured by the CPU 10 as a detection signal. The output of the switch returns to the original when the memory card 2 is pushed out by the eject mechanism. In some cases, the user pushes the memory card 2 pushed out by the ejection mechanism again into the storage unit 16 without pulling out the memory card 2. The card omission detection circuit 19 does not operate when pushed in during installation.

  The other circuit 20 implements various functions including basic functions such as calling, e-mail, and Web site browsing. Other circuits 20 include a display circuit for reproducing video content recorded on the memory card 2 and a power supply circuit having a main power supply battery.

  FIG. 3 shows the configuration of FAT (File Allocation Table) information 5 which is control information when the memory card 2 is an SD card. In addition to the user area, the memory card 2 has a partition area indicating the format of the file system and the position of the first sector, and a system area in which other management information is stored. The information stored in these partition area and system area is FAT information 5. The size of the file allocation table (FAT) 5g included in the FAT information 5 increases as the number of files recorded in the user area increases.

  FIG. 4 shows a functional configuration related to access to the memory card 2 in the mobile phone 1. As shown in FIG. 6, the mobile phone 1 includes an access processing unit 101, a FAT information management unit 102, a card drop detection unit 103, a power control unit 104, a content playback unit 120, and an audio output control unit 121. These are functional elements realized by the CPU 10 executing the control program.

  The access processing unit 101 accesses the memory card 2 in response to the access request. For example, when playing back music content, the content playback unit 120 requests access to the access processing unit 101. The access processing unit 101 reads out the requested music data from the memory card 2 and delivers it to the content reproduction unit 120. The music data is sent to the audio circuit 13 via the audio output control unit 121. The access processing unit 101 performs the first or second access described above.

  The FAT information management unit 102 stores the FAT information 5 read from the memory card 2 in the RAM 12. The FAT information 5 is referred to the access processing unit 101 at the time of the second access.

  The card drop detection unit 103 monitors the output of the card drop detection circuit 19 and detects whether the memory card 2 is removed. The detection information is given to the access processing unit 101. At the time when the access processing unit 101 receives the access request, if the previous removal of the memory card 2 has not been detected, the first response to the access request based on the FAT information 5 managed by the FAT information management unit 102 Is accessed. When the removal of the memory card 2 is detected, the FAT information 5 is read from the memory card 2 again, and the second access that responds to the access request is performed.

  The power control unit 104 controls the power supply circuit 18 that is an access power supply so as to reduce unnecessary power consumption by the memory card 2. The power control unit 104 includes a power saving setting unit 105 that switches the power supply mode of the memory card 2. The power saving setting unit 105 receives the access end notification from the access processing unit 101, and measures the waiting time for shifting from the normal mode to the power saving mode. For example, when a waiting time of 2 seconds elapses without access, the power saving mode is set.

  The flowchart of FIG. 5 shows an outline of operations related to access to the memory card 2 in the mobile phone 1.

  When the card removal detection unit 103 detects the removal of the memory card 2, the FAT information management unit 102 changes the status from “FAT read” to “FAT not read” (# 1, # 6). If removal of the memory card 2 is not detected, the access processing unit 101 checks the status managed by the FAT information management unit 102 (# 2). If the status is “FAT unread”, the access processing unit 101 reads the FAT information 5 (# 7). The read FAT information 5 is managed by the FAT information management unit 102 in place of the previously read information. When the FAT information 5 is received from the access processing unit 101, the FAT information management unit 102 changes the status from “FAT unread” to “FAT read”.

  If the status is “FAT read” in the check in step # 2, the access processing unit 101 performs the requested access (# 3).

  Thereafter, if the state of no access continues for a set time (in this example, 2 seconds) or longer, the power control unit 104 sets the power saving mode (# 4, # 5).

  While waiting for the transition to the power saving mode and after the transition, the process returns to step # 1 to repeat the routine of FIG.

  Although the mobile phone 1 has been exemplified in the above embodiment, the above access method in which the first and second accesses are mixed can also be applied to other portable information terminals such as PDAs and stationary information terminals. The above access method can also be applied when using a memory card of a standard other than an SD card, a compact flash (registered trademark), a memory stick, or other removable storage media.

  The waiting time for the transition from the normal mode to the power saving mode after the access is not limited to the illustrated two seconds, and may be appropriately selected according to the use and usage status of the memory card 2.

1 Mobile phone (information terminal)
2 Memory card (removable storage medium)
101 Access processing unit (processing unit)
5 FAT information (control information)
102 FAT information management unit (information management unit)
103 Card missing detection unit (detection unit)
104 Power control unit 18 Power supply circuit (Power supply for access)

Claims (6)

An information terminal in which a storage medium can be attached and detached,
A processing unit that receives an access request and accesses the storage medium in a state in which the storage medium is mounted;
An information management unit for storing control information read from the storage medium;
A detection unit for detecting the presence or absence of removal of the storage medium,
The processing unit does not read the control information from the storage medium based on the control information acquired from the information management unit when removal is not detected by the detection unit since the previous access. In response to an access request, when removal is detected by the detection unit, the information terminal reads the control information from the storage medium and responds to the access request. Further, a power control unit that switches the mode of power supply to the mounted storage medium from the normal mode that is the mode at the time of access to the power saving mode when a certain time has passed without the access from the end of the access by the processing unit The information terminal according to claim 1. An access method for a removable storage medium that is accessed while attached to a device, comprising:
Store control information read from the removable storage medium,
Detecting the removal of the removable storage medium,
When the removal is not detected, the removable storage medium is accessed without reading the control information from the removable storage medium based on the stored control information, and when the removal is detected. An access method for a removable storage medium, comprising: reading control information from a removable storage medium and accessing the removable storage medium based on the read control information. An access method for a removable storage medium that is accessed while attached to a device, comprising:
Store control information read from the removable storage medium,
Detecting whether or not the removable storage medium is removed from the device in a power saving mode in which an output of an access power source provided in the device is reduced compared to a normal mode;
In the first access after switching from the power saving mode to the normal mode, if the removal is not detected, the control information stored without reading the control information from the removable storage medium is referred to. An access method for a removable storage medium, wherein, when removal is detected, the control information is read from the removable storage medium and the read control information is referred to. A computer program for a computer provided in an information terminal capable of attaching and detaching a storage medium,
When executed by the computer,
Information management means for storing control information read from the storage medium;
Detecting means for detecting presence or absence of removal of the storage medium;
Means for accessing the storage medium in response to an access request in a state in which the storage medium is mounted, and if the removal is not detected by the detection means since the previous access, the information management means In response to an access request without reading the control information from the storage medium based on the stored control information, if removal is detected by the detection means, the control information is read from the storage medium. A computer program that causes the computer to realize processing means for reading the message and responding to an access request.   The computer program according to claim 6, further causing the computer to realize power control means for controlling supply power for access to the mounted storage medium.

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