Abstract:
A disk apparatus has a memory storing boot-information; and a stop section which reads, upon receipt of a stop event, the boot-information from a disk and checks the read information against the boot-information in the memory. This section updates contents of the memory to store therein the same boot-information as that in the disk and writes flag-information indicating that the same boot-information is stored in the memory when a difference is found by the checking. The apparatus also has a start section which judges, upon receipt of a start event, whether or not the flag-information is stored in the memory, reads the boot-information from the memory and activates a device used with the apparatus while deleting the flag-information when the flag-information is stored. This section reads the boot-information from the disk to activate the device and writes the read boot-information in the memory when the flag-information is not stored.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an electronic apparatus including a disk apparatus which makes access to a disk such as a hard disk and a magneto optical disk by rotating the disk while freely stopping the disk and a disk apparatus which makes access to a disk in which information is written and read by rotating the disk while freely stopping the disk. 
         [0003]    2. Description of the Related Art 
         [0004]    Recently, portable devices such as a so-called notebook type personal computer (notebook PC) into which a hard disk apparatus is incorporated become widespread. The hard disk apparatus makes access to the disc-shape hard disk in which the information is written and read during the rotation of the disk by rotating the hard disk while freely stopping the hard disk. 
         [0005]      FIG. 11  is a block diagram showing a conventional hard disk apparatus incorporated into the notebook PC. 
         [0006]    A hard disk apparatus  100  of  FIG. 11  includes plural disc-shape hard disks  101  in which the information is written and read during rotation of the hard disk. The hard disk apparatus  100  includes plural heads which make access to the disc-shape hard disk  101  while coming close to the surfaces of the hard disks  101 . The hard disk apparatus  100  includes a head circuit  102  having plural preamplifier units corresponding to the plural heads. In the head circuit  102 , the preamplifier unit amplifies a signal indicating the information from the hard disk  101  which is read by the head arranged corresponding to the hard disk  101 , and a signal for writing the information in the hard disk  101  is supplied to the head while the preamplifier unit is used as a buffer. 
         [0007]    The hard disk apparatus  100  also includes a head selection circuit  103 , a recording and reproducing circuit  104 , a serial-parallel conversion circuit  105 , a disk control circuit  106 , an interface control circuit  107 , and a buffer memory  108 . 
         [0008]    The head selection circuit  103  outputs the signal from the selected head to the recording and reproducing circuit  104 , and the head selection circuit  103  outputs the signal from the recording and reproducing circuit  104  to the selected head. 
         [0009]    The recording and reproducing circuit  104  outputs a reproducing serial signal from the head selection circuit  103  to the serial-parallel conversion circuit  105 , and also outputs a recording serial signal for recording to the hard disk  101  transmitted from the serial-parallel conversion circuit  105  to the head selection circuit  103 . 
         [0010]    The serial-parallel conversion circuit  105  converts a parallel signal from the disk control circuit  106  into the serial signal to output the converted signal to the recording and reproducing circuit  104 , and the serial-parallel conversion circuit  105  converts the serial signal from the recording and reproducing circuit  104  into the parallel signal. 
         [0011]    The disk control circuit  106  inputs the parallel signal from the serial-parallel conversion circuit  105 , constructs the inputted parallel signal in a sector unit including the predetermined number of bytes to perform error correction and the like, and outputs the signal through the interface control circuit  107  to a CPU  200  included in the notebook PC into which the hard disk apparatus  100  is incorporated. The disk control circuit  106  performs a coding process to the parallel signal inputted from the CPU  200  through the interface control circuit  107 , and outputs the signal to the serial-parallel conversion circuit  105 . 
         [0012]    The interface control circuit  107  controls the disk control circuit  106  and the buffer memory  108  based on a command from the CPU  200 , and transfers the parallel signal from the disk control circuit  106  or the buffer memory  108  to the CPU  200 . 
         [0013]    The buffer memory  108  is a volatile memory in which contents are deleted when the power is turned off. The parallel signal inputted from the CPU  200  through the interface control circuit  107  is tentatively stored in the buffer memory  108 , and also the parallel signal inputted from the serial-parallel conversion circuit  105  through the disk control circuit  106  is tentatively stored in the buffer memory  108 . 
         [0014]    In the portable device into which the hard disk apparatus is incorporated, there is a demand for shortening a start-up time necessary to become a user working environment in which the user can work after the power is turned on. For this end, it is necessary to rapidly start up an operating system (hereinafter abbreviated to OS) which controls the portable device. OS is stored in the hard disk apparatus and thus, it is important to shorten the start-up time of the hard disk apparatus to rapidly start up the portable device. However, in the hard disk apparatus, a predetermined time is required until the hard disk is stably rotated after the power is turned on. There is a problem that the information stored in the hard disk can be read or the information can be written into the disk only after the predetermined time elapses. 
         [0015]    Japanese Patent Application Laid-Open No. 2003-216435 discloses a technique wherein, in a computer system including a hard disk apparatus and a main memory, OS boot information is stored in a nonvolatile memory provided in the hard disk apparatus, the boot information is read from the nonvolatile memory and transferred to a main memory before a motor of the hard disk apparatus reaches a steady speed, and thereby the start-up time is shortened in the hard disk apparatus after the power is turned on. 
         [0016]    Japanese Patent Application Laid-Open No. 10-254770 discloses a technique wherein, in an information processing device including a hard disk apparatus, a nonvolatile memory, a cache memory and a signal processing unit, pieces of information on a storage position, an amount of data, data reading order of an OS read from the hard disk apparatus are stored in the nonvolatile memory, the OS is read from the hard disk apparatus and stored in the cache memory based on the pieces of information stored in the nonvolatile memory when the power is turned on to confirm the normal operation of the hard disk apparatus, and the signal processing unit performs the process with OS stored in the cache memory when a read command is issued from the signal processing unit at the time an initializing operation is finished in the whole of the information processing device. According to the technique disclosed in Japanese Patent Application Laid-Open No. 10-254770, OS is read from the cache memory to perform the process at the time the initializing operation is finished, so that the start-up time can be shortened in the information processing device compared with the case where OS is read from the hard disk apparatus at the time the initializing operation is finished. 
         [0017]    Japanese Patent Application Laid-Open No. 8-137622 discloses a technique wherein a nonvolatile memory in which a particular address range of an address space of a hard disk apparatus is allocated is provided in the hard disk apparatus, the access is made to the nonvolatile memory when a disk address indicated by a disk access command from a host apparatus is located within the particular address range, and thereby the speed-up in reading the data is achieved in the particular address range. 
         [0018]    Japanese Patent Application Laid-Open No. 7-44325 discloses a technique wherein a nonvolatile memory is provided in a hard disk apparatus, information necessary to load an OS in the hard disk apparatus is stored in the nonvolatile memory, and the information is read from the nonvolatile memory to shorten the start-up time of the hard disk apparatus when the hard disk apparatus is started up. 
         [0019]    Japanese Patent Application Laid-Open No. 2004-30184 discloses a technique wherein, in booting a personal computer with an OS, the OS previously stored in the hard disk apparatus is re-constructed into a data array that can be read at high speed and stored in the hard disk apparatus, and the boot process is performed at high speed with the OS in which the data array is reconstructed, when the personal computer is booted. 
         [0020]    Because a portable device into which a hard disk apparatus is incorporated is frequently driven by a battery, low power consumption is a large problem in the hard disk apparatus. In order to lengthen a battery life as long as possible, frequently the power is turned off during nonuse of the portable device while the power is turned on in use. Therefore, start-up time shortening is also the important problem in the hard disk apparatus. Sometimes OS stored in the hard disk apparatus is updated (version-up) while the power is turned on. However, in the techniques disclosed in Japanese Patent Application Laid-Open No. 2003-216435, Japanese Patent Application Laid-Open No. 8-137622, and Japanese Patent Application Laid-Open No. 7-44325, there is no description concerning the process performed in the nonvolatile memory when the power is turned on again after the power is turned off. Accordingly, even if the OS is updated while the power is turned on, there is a risk of booting the device with pre-update OS when the power is turned on again after the power is turned off. 
         [0021]    In the technique disclosed in Japanese Patent Application Laid-Open No. 10-254770, after the power is turned on, it is necessary to wait to read the OS from the hard disk apparatus until the hard disk is stably rotated at the predetermined number of revolutions. In the technique disclosed in Japanese Patent Application Laid-Open No. 2004-30184, after the power is turned on, it is necessary to wait to read the data of the OS in which the data array is reconstructed from the hard disk apparatus until the hard disk is stably rotated at the predetermined number of revolutions. Accordingly, it is difficult to shorten the start-up time of the hard disk apparatus. 
         [0022]    The hard disk apparatus includes a motor which stably rotates the hard disk at the predetermined number of revolutions while the information stored in the hard disk is read or the information is written in the hard disk. The motor requires relatively large power consumption, which makes the hard disk apparatus require large power consumption as well. 
         [0023]    Conventionally, information to be written in the hard disk which is transmitted from the outside is tentatively stored in a buffer memory included in the hard disk apparatus, the motor is driven to rotate the hard disk at the time the write information reaches a predetermined capacity so as to transfer the information to be written in the hard disk to the hard disk. Therefore, low power consumption can be achieved in the hard disk apparatus as compared with the case where the write information is written in the hard disk by driving the motor in each time the write information is transmitted from the outside. 
         [0024]    Although the conventional buffer memory is a volatile memory in which contents is deleted when the power is turned off, the power is turned off after the information stored in the buffer memory is transferred to the hard disk, when a command for turning off the power is received. However, sometimes there is a case where the power is turned off because a power cord is mistakenly removed or battery voltage is decreased. In this case, the electric power necessary for the power turn-off process cannot be supplied to the hard disk apparatus, so that the information cannot be transferred to the hard disk or the transfer is interrupted. In such cases, the power is turned on again, the hard disk information is read to confirm contents after the hard disk is stably rotated at the predetermined number of revolutions, and the necessary information is written in the buffer memory from the outside again. Accordingly, it is difficult to achieve start-up time shortening and low power consumption. 
         [0025]    In other conventional disk apparatus such as a magneto optical disk apparatus including a magneto optical disk, there is also a problem that start-up time shortening and low power consumption is hardly achieved. 
       SUMMARY OF THE INVENTION 
       [0026]    The present invention has been made in view of the above circumstances and provides a disk apparatus in which start-up time shortening and low power consumption are achieved, and an electronic apparatus including the disk apparatus. 
         [0027]    A first disk apparatus according to the invention is a disk apparatus which is incorporated into or connected to a device to make access to a disk during rotation of the disk by rotating the disk while freely stopping the disk, information including boot information necessary to start up the device being written and read in the disk, the disk apparatus including: 
         [0028]    a nonvolatile memory in which the boot information is stored; 
         [0029]    an operation stop processing section which reads, upon receipt of a predetermined operation stop event, the boot information stored in the disk from the disk, the operation stop processing section checking the read boot information against the boot information stored in the nonvolatile memory, the operation stop processing section updating contents of the nonvolatile memory in order to store the same boot information as the boot information stored in the disk in the nonvolatile memory and writing flag information indicating that the same boot information as the boot information stored in the disk is stored in the nonvolatile memory when a difference exists as a result of the checking; and 
         [0030]    an operation start processing section which judges, upon receipt of a predetermined operation start event, whether or not the flag information is stored in the nonvolatile memory, the operation start processing section reading the boot information from the nonvolatile memory and starting up the device while deleting the flag information when the flag information is stored, the operation start processing section reading the boot information from the disk to start up the device and writing the boot information read from the disk in the nonvolatile memory when the flag information is not stored. 
         [0031]    In the first disk apparatus according to the invention, when the power is turned off, the boot information stored in the disk is read and checked against the boot information stored in the nonvolatile memory, and the contents of the nonvolatile memory are updated such that the same boot information as the boot information stored in the disk is stored in the nonvolatile memory, when a difference exists. The flag information indicating that the same boot information as the boot information in the disk is stored is written in the nonvolatile memory. Therefore, even if the boot information in the disk apparatus is updated in mid-course, the post-update boot information and the flag information indicating that the post-update boot information is stored are stored in the nonvolatile memory before the power is turned off. When the flag information is stored in turning on the power, the boot information is read from the nonvolatile memory to start up the device. Therefore, the device can be rapidly started up with the post-update boot information. Accordingly, the device is never started up with the pre-update boot information, and it is not necessary to wait until the disk reaches a predetermined number of revolutions, so that low power consumption can be achieved while the device is started securely and rapidly with the latest boot information. 
         [0032]    In the first disk apparatus according to the invention, preferably, the operation start processing section writes the boot information along with information indicating an address where the boot information is read on the disk when the boot information read from the disk is written in the nonvolatile memory, and 
         [0033]    the operation stop processing section refers to, upon receipt of an operation stop event, the nonvolatile memory to obtain the information indicating the address where the boot information is stored in the disk, the operation stop processing section reading the boot information stored in the disk from the address of the disk. 
         [0034]    In this way, the address of the boot information is written in the nonvolatile memory, the operation stop event is received to obtain address information by referring to the nonvolatile memory, and the boot information in the disk is read from the address and checked against the boot information stored in the nonvolatile memory. When a difference is found in the check, the boot information stored in the boot information can be updated into the boot information read from the address. 
         [0035]    In the first disk apparatus according to the invention, preferably, when an address where the boot information is stored in the disk is changed, the operation stop processing section stops working for rewriting the boot information stored in the nonvolatile memory into the same boot information as the boot information stored in the disk, and deletes the flag information or maintains the flag information in the deleted state. 
         [0036]    When the address where the boot information in the disk is stored is changed, the flag information is deleted or the flag information is maintained in the deleted state, the process of reading the boot information in the disk to start up the device and of writing the boot information read from the disk in the nonvolatile memory is performed after the disk has reached a stable state of a predetermined number of revolutions since the power is turned on. Even if the address of the boot information is changed, the same boot information as the boot information stored in the disk cannot be written in the nonvolatile memory because the electric power necessary for the power turn-off process cannot be supplied to the disk apparatus. Accordingly, the device can be normally started up like the case where the flag information is not written in the nonvolatile memory. When the power is turned on again, the device can be rapidly started up with the boot information stored in the nonvolatile memory. 
         [0037]    In the first disk apparatus according to the invention, preferably the boot information is comprised of master boot record information, boot sector information, and kernel information. 
         [0038]    The master boot record information, the boot sector information, and the kernel information are of the most basic information in the functions necessary to start up the device. The master boot record information, the boot sector information, and the kernel information are stored in the nonvolatile memory, so that the device can be rapidly started up. 
         [0039]    A second disk apparatus according to the invention is a disk apparatus which is incorporated into or connected to a device to make access to a disk during rotation of the disk by rotating the disk while freely stopping the disk, information including boot information necessary to start up the device being written and read in the disk, the disk apparatus including: 
         [0040]    a nonvolatile memory; 
         [0041]    a write processing section which tentatively stores information to be written in the disk in the nonvolatile memory, and transfers the information in the nonvolatile memory to the disk to delete the information stored in the nonvolatile memory in each time the information reaches a predetermined capacity in the nonvolatile memory; 
         [0042]    an operation stop processing section which judges, upon receipt of a predetermined operation stop event, whether or not the information to be written in the disk is stored in the nonvolatile memory, the operation stop processing section transferring the information to the disk when the information is stored in the nonvolatile memory; and 
         [0043]    an operation start processing section which judges, upon receipt of a predetermined operation start event, whether or not the information to be written in the disk is stored in the nonvolatile memory, the operation start processing section transferring the information to the disk when the information is stored in the nonvolatile memory. 
         [0044]    In the second disk apparatus according to the invention, when the write information is stored in the nonvolatile memory in turning off the power, the write information is transferred to the disk. When the write information is stored in the nonvolatile memory in turning on the power, the write information is transferred to the disk. Therefore, even when the power is turned off because a power cord is mistakenly removed or a battery voltage is decreased and thus, the electric power necessary for a power turn-off process cannot be supplied to the disk apparatus and the information cannot be transferred to the hard disk  101  or the transfer is interrupted, the write information stored in the nonvolatile memory can be transferred to the disk after the disk has reached a stable state of a predetermined number of revolutions since the power is turned on. In a conventional process performed in a disk apparatus including a volatile memory in which write information is stored, when the power is turned on again, the information on the disk is read to confirm the contents after the disk is stably rotated at the predetermined number of revolutions, and the necessary information is written in a buffer memory from the outside. Accordingly, the conventional process is not required in the disk apparatus, so that start-up time shortening and low power consumption can be achieved. 
         [0045]    A first electronic apparatus according to the invention is an electronic apparatus including a disk apparatus which makes access to a disk by rotating the disk while freely stopping the disk, information being written and read in the disk, the electronic apparatus being started up by boot information read from the disk apparatus in which the boot information necessary to start up the disk apparatus is stored, 
         [0046]    wherein the disk apparatus includes: 
         [0047]    a nonvolatile memory in which the boot information is stored; 
         [0048]    an operation stop processing section which reads, upon receipt of a predetermined operation stop event, the boot information stored in the disk from the disk, the operation stop processing section checking the read boot information against the boot information stored in the nonvolatile memory, the operation stop processing section updating contents of the nonvolatile memory in order to store the same boot information as the boot information stored in the disk in the nonvolatile memory and writing flag information indicating that the same boot information as the boot information stored in the disk is stored in the nonvolatile memory when a difference exists as a result of the checking; and 
         [0049]    an operation start processing section which judges, upon receipt of a predetermined operation start event, whether or not the flag information is stored in the nonvolatile memory, the operation start processing section reading the boot information from the nonvolatile memory and starting up the device while deleting the flag information when the flag information is stored, the operation start processing section reading the boot information from the disk to start up the device and writing the boot information read from the disk in the nonvolatile memory when the flag information is not stored. 
         [0050]    The first electronic apparatus according to the invention includes the first disk apparatus according to the invention. Therefore, the device is never started up with the pre-update boot information, and it is not necessary to wait until the disk reaches the predetermined number of revolutions, so that low power consumption can be achieved while the device is started securely and rapidly with the latest boot information. 
         [0051]    In the first electronic apparatus according to the invention, preferably, the operation start processing section writes the boot information along with information indicating an address where the boot information is read on the disk when the boot information read from the disk is written in the nonvolatile memory, and 
         [0052]    the operation stop processing section refers to, upon receipt of the operation stop event, the nonvolatile memory to obtain the information indicating the address where the boot information is stored in the disk, the operation stop processing section reading the boot information stored in the disk from the address of the disk. 
         [0053]    Further, in the first electronic apparatus according to the invention, preferably, when an address where the boot information is stored in the disk is changed, the operation stop processing section stops working for rewriting the boot information stored in the nonvolatile memory into the same boot information as the boot information in the disk, and deletes the flag information or maintains the flag information in the deleted state. 
         [0054]    Furthermore, in the first electronic apparatus according to the invention, preferably, the boot information is comprised of master boot record information, boot sector information, and kernel information. 
         [0055]    A second electronic apparatus according to the invention is an electronic apparatus including a disk apparatus which makes access to a disk by rotating the disk while freely stopping the disk, information being written and read in the disk, the electronic apparatus being started up by boot information read from the disk apparatus in which the boot information necessary to start up the disk apparatus is stored, 
         [0056]    wherein the disk apparatus includes: 
         [0057]    a nonvolatile memory; 
         [0058]    a write processing section which tentatively stores information to be written in the disk in the nonvolatile memory, the write processing section transferring the information stored in the nonvolatile memory to the disk to delete the information stored in the nonvolatile memory in each time the information reaches a predetermined capacity in the nonvolatile memory; 
         [0059]    an operation stop processing section which judges, upon receipt of a predetermined operation stop event, whether or not the information to be written in the disk is stored in the nonvolatile memory, the operation stop processing section transferring the information to the disk when the information is stored in the nonvolatile memory; and 
         [0060]    an operation start processing section which judges, upon receipt of a predetermined operation start event, whether or not the information to be written in the disk is stored in the nonvolatile memory, the operation start processing section transferring the information to the disk when the information is stored in the nonvolatile memory. 
         [0061]    The second electronic apparatus according to the invention includes the second disk apparatus according to the invention. In a conventional process performed in a disk apparatus including a volatile memory in which write information is stored, when the power is turned on again, the information on the disk is read to confirm the contents after the disk is stably rotated at the predetermined number of revolutions, and the necessary information is written in a buffer memory from the outside. Accordingly, in the second electronic apparatus according to the invention, the conventional process is not required, so that start-up time shortening and low power consumption can be achieved. 
         [0062]    Thus, the present invention can provide the disk apparatus and the electronic apparatus including the disk apparatus in which start-up time shortening and low power consumption are achieved. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0063]      FIG. 1  is a perspective view schematically showing a notebook PC into which embodiments of both a hard disk apparatus according to a first aspect of the invention and a hard disk apparatus according to a second aspect of the invention are incorporated; 
           [0064]      FIG. 2  is a block diagram showing a schematic circuit of the notebook PC of  FIG. 1 ; 
           [0065]      FIG. 3  is a block diagram showing the hard disk apparatus of  FIG. 2 ; 
           [0066]      FIG. 4  shows areas of the hard disk of  FIG. 3 ; 
           [0067]      FIG. 5  shows a structure of a first nonvolatile memory area; 
           [0068]      FIG. 6  is a flowchart showing a process performed in the first nonvolatile memory area when the power is turned off in the hard disk apparatus of  FIG. 3 ; 
           [0069]      FIG. 7  is a flowchart showing a process performed in the first nonvolatile memory area when the power is turned on in the hard disk apparatus of  FIG. 3 ; 
           [0070]      FIG. 8  is a flowchart showing a process of writing information in a second nonvolatile memory area of the hard disk apparatus of  FIG. 3 ; 
           [0071]      FIG. 9  is a flowchart showing a process performed in the second nonvolatile memory area when the power is turned off in the hard disk apparatus of  FIG. 3 ; 
           [0072]      FIG. 10  is a flowchart showing a process performed in the second nonvolatile memory area when the power is turned on in the hard disk apparatus of  FIG. 3 ; and 
           [0073]      FIG. 11  is a block diagram showing a conventional hard disk apparatus incorporated into the notebook PC. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0074]    Embodiments of the invention will be described with reference to the drawings. 
         [0075]      FIG. 1  is a perspective view schematically showing a notebook PC into which embodiments of both the hard disk apparatus according to the first aspect of the invention and the hard disk apparatus according to the second aspect of the invention are incorporated. 
         [0076]    As described in detail later, a hard disk apparatus which is of the embodiments of both the hard disk apparatus according to the first aspect of the invention and the hard disk apparatus according to the second aspect of the invention are incorporated in a notebook PC  10  of  FIG. 1 . The hard disk apparatus makes access to a disc-shape hard disk (corresponding to an example of the disk of the invention), in which information including boot information necessary to boot the notebook PC  10  is written and read during the rotation of the hard disk, by rotating the hard disk while freely stopping the hard disk. The notebook PC  10  corresponds to examples of the first and second electronic apparatus according to the invention. 
         [0077]    The notebook PC  10  includes two housings: a main body unit  20  and a display unit  30 . The display unit  30  includes a display screen  31  which displays an image, and the display unit  30  is openably supported by a hinge portion  40 . 
         [0078]    A keyboard  21  is provided in an upper surface of the main body unit  20 . The main body unit  20  includes a glide point  22 , a left click button  23  and a right click button  24 , and a fingerprint sensor  25 . The glide point  22  detects finger contact and motion of a contact finger. The left click button  23  and the right click button  24  act as a left button and a right button of a mouse respectively. The fingerprint sensor  25  which detects a fingerprint is arranged between left click button  23  and the right click button  24 . 
         [0079]    A main circuit board on which circuits such as CPU for performing various processes are mounted is incorporated into the housing of the main body unit  20 . An end face  26  of a CD/DVD drive is exposed in a right side face of the main body unit  20 . CD or DVD is loaded in the CD/DVD drive while freely taken out, and the CD/DVD drive makes access to CD or DVD during the rotation by rotating CD or DVD loaded in the CD/DVD drive. An eject button  27  is provided in the end face  26 , and a CD/DVD drive tray slides to the outside of the main body unit by pressing the eject button  27 . 
         [0080]    In the right side face of the main body unit  20 , a media slot insertion port  28  is also provided at a position where a part of the media slot insertion port  28  vertically overlaps the CD/DVD drive. Various storage mediums such as SmartMedia® and xD card® are inserted into the media slot insertion port  28  while freely taken out, and the access to the storage medium is performed through the media slot. 
         [0081]    The display unit  30  includes the display screen  31 , and a hole  32  is made in a front face cover surrounding the display screen  31 . The hole  32  introduces sound to a microphone (not shown) arranged inside. 
         [0082]    The hinge portion  40  has a structure in which the display unit  30  is openably supported by the main body unit  20 . 
         [0083]    A speaker  29  is provided at the back of the hinge portion  40  in the main body unit  20 . 
         [0084]      FIG. 2  is a block diagram showing a schematic circuit of the notebook PC of  FIG. 1 . 
         [0085]    The notebook PC  10  of  FIG. 2  includes a CPU  41 , a main memory  42 , a hard disk apparatus  43 , a flexible disk drive  44 , a CD/DVD drive  45 , and a USB communication device  46 . As shown in  FIG. 1 , the notebook PC  10  also includes the display screen  31 , the keyboard  21 , the left and right click buttons  23  and  24 , the glide point  22 , and the fingerprint sensor  25 . The CPU  41  executes various programs. In the main memory  42 , the program stored in the hard disk apparatus  43  which is of the first disk apparatus and the second disk apparatus according to the embodiment of the invention is read and expanded to execute the program using CPU  41 . The various program and image data are stored in the hard disk apparatus  43 . A flexible disk  44 _ 1  is loaded in the flexible disk drive  44 , and the flexible disk drive  44  makes access to the loaded flexible disk  44 _ 1 . The CD/DVD drive  45  makes access to a CD/DVD  45 _ 1 . The USB communication device  46  is connected to a USB communication device included in a digital camera or the like, and the USB communication device  46  captures image data from the USB communication device. These components are mutually connected through a bus  48 . 
         [0086]      FIG. 3  is a block diagram showing the hard disk apparatus  43  of  FIG. 2 . 
         [0087]    The same components as those of the hard disk apparatus  100  of  FIG. 11  are designated by the same numerals, and only the different point will be described. 
         [0088]    The hard disk apparatus  43  of  FIG. 3  includes a nonvolatile memory  430  having both a first nonvolatile memory area  431  and a second nonvolatile memory area  432  and a buffer memory  450 . 
         [0089]    The first nonvolatile memory area  431  acts as the nonvolatile memory in the first disk apparatus of the invention, and the later-mentioned boot information is tentatively stored in the first nonvolatile memory area  431 . 
         [0090]    The second nonvolatile memory area  432  acts as the nonvolatile memory in the second disk apparatus of the invention, and the information written in the hard disk apparatus  43  is tentatively stored in the second nonvolatile memory area  432 . 
         [0091]    The information from the hard disk  101  is tentatively stored in the buffer memory  450 . 
         [0092]    The hard disk apparatus  43  of  FIG. 3  includes an interface control circuit  440 , and the interface control circuit  440  includes a first operation stop processing unit  441 , a first operation start processing unit  442 , a write processing unit  443 , a second operation stop processing unit  444  and a second operation start processing unit  445 . 
         [0093]    The first operation stop processing unit  441  and the first operation start processing unit  442  correspond to examples of the operation stop processing section and the operation start processing section in the first disk apparatus of the invention, respectively. The second operation stop processing unit  444  and the second operation start processing unit  445  correspond to examples of the operation stop processing section and the operation start processing section in the second disk apparatus of the invention, respectively. First the first operation stop processing unit  441  and the first operation start processing unit  442  will be described along with the first nonvolatile memory area  431  which acts as the nonvolatile memory in the first disk apparatus of the invention. 
         [0094]    When the power of the notebook PC  10  is turned off, the first operation stop processing unit  441  receives a predetermined operation stop event from the CPU  41  to read boot information stored in the hard disk  101  from the hard disk  101 , and the first operation stop processing unit  441  checks the boot information stored in the hard disk  101  against boot information stored in the first nonvolatile memory area  431 . When a difference point exists between the two pieces of boot information, the first operation stop processing unit  441  updates contents of the first nonvolatile memory area  431  such that the same boot information as the boot information stored in the hard disk  101  is stored in the first nonvolatile memory area  431 . The first operation stop processing unit  441  writes identification information (corresponding to an example of the flag information in the invention) in the first nonvolatile memory area  431 . The identification information indicates that the same boot information as the boot information stored in the hard disk  101  is stored in the first nonvolatile memory area  431 . 
         [0095]    Specifically, when the first operation stop processing unit  441  receives the operation stop event, the first operation stop processing unit  441  refers to the first nonvolatile memory area  431  to obtain information indicating an address where the boot information in the hard disk  101  is stored, and the first operation stop processing unit  441  reads the boot information in the hard disk  101  from the address of the hard disk  101 . 
         [0096]    When the address where the boot information in the hard disk  101  is stored is changed, the first operation stop processing unit  441  stops working for rewriting the boot information in the first nonvolatile memory area  431  to the same boot information as the boot information in the hard disk  101 , and deletes the identification information or maintains the identification information in the deleted state. 
         [0097]    On the other hand, when the power of the notebook PC  10  is turned on, the first operation start processing unit  442  receives a predetermined operation start event from the CPU  41  to judge whether or not the identification information is stored in the first nonvolatile memory area  431 . When the identification information is stored in the first nonvolatile memory area  431 , the first operation start processing unit  442  reads the boot information from the first nonvolatile memory area  431  to boot the notebook PC  10 , and deletes the identification information. When the identification information is not stored in the first nonvolatile memory area  431 , the first operation start processing unit  442  reads the boot information from the hard disk  101  to boot the notebook PC  10 , and writes the boot information read from the hard disk  101  in the first volatile memory area  431 . 
         [0098]    Specifically, in writing the boot information read from the hard disk  101  in the first nonvolatile memory area  431 , the first operation start processing unit  442  writes the boot information along with information indicating the address where the boot information is read on the hard disk  101 . 
         [0099]      FIG. 4  shows areas of the hard disk of  FIG. 3 . 
         [0100]    The hard disk  101  of  FIG. 4  includes a master boot record area and partitions areas  1 ,  2 ,  3 , and  4  which have boot sector areas respectively. 
         [0101]    The master boot record area is formed by a 512-byte data area, and the 512-byte data area includes a bootstrap loader area, partition table areas  1 ,  2 ,  3 , and  4 , and a boot signature (0×AA55) area. The bootstrap loader is a program for reading the partition tables  1 ,  2 ,  3 , and  4 . A boot flag for permitting OS start-up is stored in one of the partition tables  1 ,  2 ,  3 , and  4 , and the boot flag is read with the bootstrap loader. The OS is stored in a partition area corresponding to the partition table in which the boot flag is stored, and the OS is started up by reading the boot flag with the bootstrap loader. The boot signature (0×AA55) is information for confirming that OS stored in the partition area having a boot sector area is correct. 
         [0102]    The boot sector area is formed by a 512-byte data area, and the 512-byte data area includes a jump command area, a disk parameter area, a program code area, and a boot signature (0×AA55) area. The jump command is a command for jumping to the address of the OS stored in the partition area having the boot sector area. The disk parameter indicates an attribute of the partition.  FIG. 4  also shows a file area (kernel) possessed by the partition area. The pieces of information stored in the master boot record area, boot sector area, and file area are the boot information necessary to start up OS. 
         [0103]    When the boot signature (0×AA55) stored in the boot sector area possessed by the partition area corresponding to the partition table in which the boot flag is stored is correct, the OS is started up by jumping to the address of the OS stored in the partition area. 
         [0104]      FIG. 5  shows a structure of the first nonvolatile memory area  431 . 
         [0105]    The first nonvolatile memory area  431  includes a master boot record area  431 _ 1 , a boot sector area  431 _ 2 , and a file area (kernel)  431 _ 3 , where master boot record information, boot sector information and file area information, which constitute the boot information are stored, respectively. The first nonvolatile memory area  431  has an identification area  431 _ 4  for writing the identification information. 
         [0106]      FIG. 6  is a flowchart showing a process performed in the first nonvolatile memory area  431  when the power is turned off in the hard disk apparatus of  FIG. 3 . 
         [0107]    This process is performed, when the power of the notebook PC into which the hard disk apparatus of  FIG. 3  is incorporated is turned off. 
         [0108]    In step S 1 , the operation stop processing unit receives a predetermined operation stop event from the CPU, and the operation stop processing unit refers to the first nonvolatile memory area to receive the information indicating the address where the boot information is stored in the hard disk. 
         [0109]    In step S 2 , it is judged whether or not the address in the hard disk is changed. When it is judged that the address in the hard disk is not changed, the flow goes to step S 3 . In step S 3 , the boot information in the hard disk is read from the received address. In step S 4 , the read boot information in the hard disk is checked against the boot information stored in the first nonvolatile memory area. 
         [0110]    In step S 5 , it is judged whether or not the different point exists. When the different point exists, the flow goes to step S 6 . In step S 6 , contents of the first nonvolatile memory area is updated into the same boot information as the boot information in the hard disk. Then, the flow goes to step S 7 . On the other hand, when the different point does not exist, the flow goes directly to step S 7 . 
         [0111]    In step S 7 , the identification information is written in the first nonvolatile memory area. Then, the flow goes to step S 8 . 
         [0112]    When it is judged in step S 2  that the address is changed, the identification information is deleted or the identification information is maintained in the deleted state in step S 9 . Then, the flow goes to step S 8 . 
         [0113]    In step S 8 , the power is turned off to end the flow. 
         [0114]      FIG. 7  is a flowchart showing a process performed in the first nonvolatile memory area when the power is turned on in the hard disk apparatus of  FIG. 3 . 
         [0115]    This process is performed, when the power of the notebook PC into which the hard disk apparatus of  FIG. 3  is incorporated is turned on. 
         [0116]    In step S 11 , the operation start processing unit receives a predetermined operation start event from the CPU to judge whether or not the identification information is stored in the first nonvolatile memory area. When it is judged that the identification information is stored in the first nonvolatile memory area, the flow goes to step S 12 . In step S 12 , the boot information is read from the first nonvolatile memory area and the boot information is transferred to the CPU. In step S 13 , the identification information is deleted, and the flow is ended. 
         [0117]    On the other hand, when it is judged in step S 11  that the identification information is not stored in the first nonvolatile memory area, the flow goes to step S 14 . In step S 14 , the boot information is read from the hard disk and transferred to the CPU, and the boot information is written in the first nonvolatile memory area along with the information indicating the address where the boot information is read on the hard disk, and the flow is ended. 
         [0118]    Thus, in the hard disk apparatus  43  of  FIG. 3  which is of the embodiment of the first hard disk apparatus according to the invention, when the power is turned off, the boot information stored in the hard disk  101  is read and checked against the boot information stored in the first nonvolatile memory area  431 . When the different point exists, the contents of the first nonvolatile memory area  431  is updated such that the same boot information as the boot information in the hard disk  101  is stored in the first nonvolatile memory area  431 . The identification information indicating that the same boot information as the boot information in the hard disk  101  is stored is written in the first nonvolatile memory area  431 . Therefore, even if the boot information in the hard disk apparatus  43  is updated at the mid-course, the updated boot information and the identification information indicating that the boot information is updated are stored in the first nonvolatile memory area  431  before the power is turned off. In turning on the power, when the identification information is stored, the boot information is read from the first nonvolatile memory area  431  to boot the notebook PC  10 . Therefore, the notebook PC  10  can be rapidly booted with the updated boot information. The notebook PC  10  is never booted with the pre-update boot information, and it is not necessary to wait until the hard disk  101  reaches the predetermined number of revolutions, so that low power consumption can be achieved while the notebook PC  10  is started securely and rapidly with the latest boot information. 
         [0119]    In the hard disk apparatus  43 , when the boot information read from the hard disk  101  by the first operation start processing unit  442  is written in the first nonvolatile memory area  431 , the boot information is written along with information indicating the address where the boot information is read on the hard disk  101 . When the power is turned off, the first operation stop processing unit  441  refers to the first nonvolatile memory area  431  to obtain the information indicating the address where the boot information is stored in the hard disk  101 , and the first nonvolatile memory area  431  reads the boot information stored in the hard disk  101  from the address of the hard disk  101 . Therefore, in the hard disk apparatus  43 , the address of the boot information is written in the first nonvolatile memory area  431 . When the power is turned off, the address information is obtained by referring to the first nonvolatile memory area  431 , and the boot information in the hard disk  101  is read from the address and checked against the boot information stored in the first nonvolatile memory area  431 . When a difference is found in the check, the boot information stored in the first nonvolatile memory area  431  can be rewritten into the boot information read from the address. 
         [0120]    In the hard disk apparatus  43 , when the address where the boot information in the hard disk  101  is stored is changed, the first operation stop processing unit  441  stops the working for rewriting the boot information stored in the first nonvolatile memory area  431  into the same boot information as the boot information in the hard disk  101 , and deletes the identification information or maintains the identification information in the deleted state. Therefore, the process of reading the boot information stored in the hard disk  101  to boot the notebook PC  10  and of writing the boot information read from the hard disk  101  in the first nonvolatile memory area  431  is performed after the hard disk  101  has reached a stable state of a predetermined number of revolutions since the power is turned on. Even if the address of the boot information is changed, the same boot information as the boot information stored in the hard disk  101  cannot be written in the first nonvolatile memory area  431  because the electric power necessary for the power turn-off process cannot be supplied to the hard disk apparatus  43 . Accordingly, the notebook PC  10  can be normally booted like the case where the identification information is not written in the first nonvolatile memory area  431 . When the power is turned on again, the notebook PC  10  can be rapidly booted with the boot information written in the first nonvolatile memory area  431 . 
         [0121]    The boot information in the hard disk apparatus  43  includes the master boot record information, boot sector information, and kernel information, which are of the most basic information in the functions necessary to boot the notebook PC  10 . The master boot record information, boot sector information, and kernel information are stored in the first nonvolatile memory area  431 , so that the notebook PC  10  can be rapidly booted. 
         [0122]    Then, returning to  FIG. 3 , the second operation stop processing unit  444  and the second operation start processing unit  445  which are of examples of the operation stop processing section and the operation start processing section in the second hard disk apparatus of the invention, respectively, will be described along with the write processing unit  443  which is of an example of the write processing section in the second hard disk apparatus of the invention and the second nonvolatile memory area  432  which acts as the nonvolatile memory in the second hard disk apparatus of the invention. 
         [0123]    The write processing unit  443  of  FIG. 3  tentatively stores information to be written in the hard disk  101  in the second nonvolatile memory area  432 , and transfers the information stored in the second nonvolatile memory area  432  to the hard disk  101  to delete the information stored in the second nonvolatile memory area  432  when information to be written in the hard disk  101  reaches a predetermined capacity in the second nonvolatile memory area  432 . 
         [0124]    When the power of the notebook PC  10  is turned off, the second operation stop processing unit  444  receives a predetermined operation stop event from the CPU  41  to judge whether or not information to be written in the hard disk  101  is stored in the second nonvolatile memory area  432 . When the information to be written in the hard disk  101  is stored in the second nonvolatile memory area  432 , the second operation stop processing unit  444  transfers the information to the hard disk  101 . 
         [0125]    When the power of the notebook PC  10  is turned on, the second operation start processing unit  445  receives a predetermined operation start event from the CPU  41  to judge whether or not the information to be written in the hard disk  101  is stored in the second nonvolatile memory area  432 . When the information to be written in the hard disk  101  is stored in the second nonvolatile memory area  432 , the second operation start processing unit  445  transfers the information to the hard disk  101 . 
         [0126]      FIG. 8  is a flowchart showing a process of writing information in a second nonvolatile memory area of the hard disk apparatus of  FIG. 3 . 
         [0127]    The write process is performed after the power of the notebook PC  10  into which the hard disk apparatus  43  of  FIG. 3  is incorporated is turned on to start up the OS. 
         [0128]    In step S 21 , the write information is transferred from the CPU to the second nonvolatile memory area. 
         [0129]    In step S 22 , it is judged whether or not the write information stored in the second nonvolatile memory area has reached a predetermined capacity. When it is judged that the write information stored in the second nonvolatile memory area has not reached the predetermined capacity, the flow goes to step S 23 . In step S 23 , it is judged whether or not the write information from the CPU is finished. When it is judged that the write information from the CPU is not finished, the flow returns to step S 21 . On the other hand, when it is judged that the write information from CPU is finished, the flow is ended. 
         [0130]    In step S 22 , when it is judged that the write information reaches the predetermined capacity, the flow goes to step S 24 . In step S 24 , the write information in the second nonvolatile memory area is transferred to the hard disk. In step S 25 , the write information in the second nonvolatile memory area is deleted, and the flow is ended. 
         [0131]      FIG. 9  is a flowchart showing a process performed in the second nonvolatile memory area when the power is turned off in the hard disk apparatus of  FIG. 3 . 
         [0132]    This process is performed, when the power of the notebook PC  10  into which the hard disk apparatus  43  of  FIG. 3  is incorporated is turned off. 
         [0133]    In step S 31 , the second operation stop processing unit receives a predetermined operation stop event from the CPU to judge whether or not write information is stored in the second nonvolatile memory area. When it is judged that the write information is stored in the second nonvolatile memory area, the flow goes to step S 32 . 
         [0134]    In step S 32 , the write information of the second nonvolatile memory area is transferred to the hard disk, and the flow goes to step S 33 . 
         [0135]    In step S 31 , when it is judged that the write information is not stored in the second nonvolatile memory area, the flow goes directly to step S 33 . 
         [0136]    In step S 33 , the power is cut off to end the flow. 
         [0137]      FIG. 10  is a flowchart showing a process performed in the second nonvolatile memory area when the power is turned on in the hard disk apparatus of  FIG. 3 . 
         [0138]    This process is performed, when the power of the notebook PC  10  into which the hard disk apparatus  43  of  FIG. 3  is incorporated is turned on. 
         [0139]    In step S 41 , the operation start processing unit receives a predetermined operation start event from the CPU to judge whether or not the write information is stored in the second nonvolatile memory area. When it is judged that the write information is stored in the second nonvolatile memory area, the flow goes to step S 42 . 
         [0140]    In step S 42 , the write information of the second nonvolatile memory area is transferred to the hard disk, and the flow is ended. 
         [0141]    In step S 41 , when it is judged that the write information is not stored in the second nonvolatile memory area, the flow is directly ended. 
         [0142]    Thus, in the hard disk apparatus  43  of  FIG. 3  which is of the embodiment of the second hard disk apparatus according to the invention, when the write information is stored in the second nonvolatile memory area  432  in turning off the power, the write information is transferred to the hard disk  101 . When the write information is stored in the second nonvolatile memory area  432  in turning on the power, the write information is transferred to the hard disk  101 . Even when the power is turned off because the power cord is mistakenly removed or the battery voltage is decreased and thus, the electric power necessary for the power turn-off process cannot be supplied to the hard disk apparatus  43  and the information cannot be transferred to the hard disk  101  or the transfer is interrupted, the write information stored in the second nonvolatile memory area  432  can be transferred to the hard disk  101  after the hard disk  101  has reached a steady state of a predetermined number of revolutions since the power is turned on. In the conventional process performed in the hard disk apparatus including the volatile memory in which the write information is stored, when the power is turned on again, information on the hard disk is read to confirm the contents after the hard disk is stably rotated at the predetermined number of revolutions, and necessary information is written in the buffer memory from the outside. Accordingly, such conventional process is not required in the hard disk apparatus  43 , and thus start-up time shortening and low power consumption can be achieved. 
         [0143]    In the embodiments, the hard disk apparatus incorporated into the notebook PC is described by way of example. However, the invention is not limited thereto, but the invention can be applied to any hard disk apparatus being incorporated into or connected to a device to make access to a disk in which information including boot information necessary to start up the device is written and read during the rotation of the disk by rotating the disk while freely stopping the disk. 
         [0144]    In the embodiments, the electronic apparatus of the invention is applied to the notebook PC by way of example. However, the invention is not limited to thereto, but the electronic apparatus of the invention can generally be applied to any electronic apparatus including a disk apparatus making access to a disk in which information is written and read by rotating the disk while freely stopping the disk, the electronic apparatus being started up with boot information read from the disk apparatus in which the boot information necessary to start up the electronic apparatus is written.