JP2004005423A - File data storage managing method, file data storage device, program executing processing for storing file data, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently store real-time file data, having large capacity with suppressing fragmentation generated by repeatedly storing and erasing file data having small capacity. <P>SOLUTION: A unit is constituted from a block, depended on a physical storage unit and also a plurality of contiguous blocks. This unit is configured to capacity, to assure real-time processing. The real-time file data, such as video data are stored in units. The data to be processed in non-real-time are stored in units of the block. A unit management table is arranged, and whether the unit is available at recording is recognized, on the basis of the unit management table. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a file data storage management method, a file data storage device, a program for executing a process for storing file data, and a storage medium, and more particularly to a method capable of efficiently storing real-time file data and non-real-time file data. It is.
[0002]
[Prior art]
When storing data constituting one file (hereinafter, referred to as file data) in a storage medium, a method of allocating file data to blocks obtained by dividing a storage area of the storage medium into a predetermined same capacity is adopted. In this file storage method, use / non-use of each block is managed by a block management table.
[0003]
The storage of file data is performed by searching for unused blocks by referring to the block management table and allocating a plurality of unused blocks for data storage according to the capacity of the file data. At this time, a file configuration table indicating which block is used to store the file information is created. As this file configuration table, for example, a FAT (File \ Allocation \ Table) is used. The FAT defines the physical connection of the blocks making up the file. Specifically, using a unique block number assigned to a block, a table is created for all blocks in the storage area, in which the block numbers are associated with the numbers of the blocks logically following the blocks. .
[0004]
[Problems to be solved by the invention]
When storing file data having a capacity equal to or greater than the block length, for example, data having a large storage capacity such as video and audio, the file data is stored over a plurality of blocks. Here, if data is intermittently stored in physically discontinuous areas on the storage medium, when these data are processed in real time and read out, it is necessary to smoothly perform access depending on the moving time of the drive head. And it may be difficult to perform continuous data processing. Therefore, in consideration of storage of such large-volume data that is processed in real time, it is desirable to set the capacity of one block to be large and to secure a physically continuous area as much as possible.
[0005]
On the other hand, the data capacity of a file varies depending on the type of the file, and there is also a file having a very small data capacity such as a very small document file.
[0006]
However, in the current file storage method, file data is stored in block units, so that two or more file data cannot be stored in one block. Therefore, if the capacity of the block is set too large, the free space in each block in which actual data is not stored but data of another file cannot be stored increases. There is a problem that the use efficiency of the area is significantly reduced.
[0007]
On the other hand, if the capacity of the blocks is made too small, the number of linked blocks becomes very large when recording large-capacity file data, and there is a concern that the access performance when reading these data may be degraded. You.
[0008]
In addition, if data is repeatedly stored and erased due to frequent input / output of data, it becomes difficult to secure a physically continuous free area, and so-called fragmentation (fragmentation) occurs. obtain.
[0009]
FIG. 14 shows an example of file data allocation to a storage medium, a block management table at that time, and a use state of each block. In the block management table of FIG. 1, 1 indicates a state where the block is used, and 0 indicates a state where the block is unused. A hatched portion 30x in the figure is a used block, and a plain portion 30y is an unused empty block. In FIG. 14, empty blocks are scattered, and fragmentation has occurred.
[0010]
On the other hand, for example, as shown in FIG. 15, the management table can be configured so that four blocks are regarded as one block. By increasing the data volume handled in the block management table in this way, the above-described fragmentation problem can be solved to some extent. However, in this case, as described above, the use efficiency of the storage area is significantly reduced.
[0011]
Therefore, the present invention solves such a problem and, while allocating file data suitable for storage and reproduction of a real-time file, simultaneously suppresses the occurrence of fragmentation, thereby efficiently storing small-sized file data. It is an object to provide a data storage method that can be reproduced.
[0012]
[Means for Solving the Problems]
According to the present invention, a unit is composed of a plurality of continuous blocks, and the attributes of the unit are managed by a unit attribute table. The unit attribute table includes the usage status of each unit and information defining whether real-time data can be stored.
[0013]
When the file data to be stored is real-time data, an unused unit capable of storing real-time data is searched by referring to the unit attribute table, and the file data is stored in the block included in the searched unit. Is done. Further, when the stored file data is non-real-time data, the unit attribute table is referred to to search for a unit in which non-real-time data is already stored in some blocks in the unit. The file data is stored in an unused block included in the acquired unit.
[0014]
As described above, the number of unused units can be increased by changing the recording process depending on whether the file data to be stored is real-time data or non-real-time data. Will be able to do it.
[0015]
One aspect of the present invention is, for example, a block management table for managing whether data is stored in a block, a unit attribute table for managing attributes of a unit composed of a plurality of continuous blocks, And a data storage process for storing file data based on the attribute table.
[0016]
Here, the unit attribute table includes the usage status of each unit and information defining whether or not real-time data can be stored. Further, when the file data to be stored is real-time data, the data storage process refers to the unit attribute table to search for an unused unit capable of storing real-time data, and includes the unit included in the searched unit. When this file data is stored in a block and the stored file data is non-real-time data, a unit in which the non-real-time data is already stored in some blocks in the unit is referred to by referring to the unit attribute table. , And storing the file data in an unused block included in the unit obtained by the search.
[0017]
Another aspect of the present invention provides, for example, a unit for generating a block management table for managing whether data is stored in a block, and a unit for managing attributes of a unit composed of a plurality of continuous blocks. It can be understood as a file data storage device including a unit for generating an attribute table and a unit for executing processing for storing file data based on the unit attribute table.
[0018]
Still another aspect of the present invention provides, for example, a process of generating a block management table that manages whether data is stored in a block, and forming a unit from a plurality of continuous blocks, and It can also be grasped as a program for executing a process including a process of generating a unit attribute table for managing attributes and a process including a data storage process of storing file data based on the unit attribute table.
[0019]
Still another aspect of the present invention provides, for example, at least, in addition to main data, at least a block management table for managing whether data is stored in the block, and an attribute of a unit constituted by a plurality of continuous blocks. Can be grasped as a storage medium in which a unit attribute table for managing is stored.
[0020]
As an improvement of each of the above aspects, the attribute management table may further include information defining a rank of a write and / or read rate for each unit. At this time, when the file data to be stored is real-time data, the data storage processing in each aspect refers to the unit attribute table to store unused file data satisfying the write and / or read rate required for the file data. A process of searching for the unit and storing the file data in the block included in the searched unit.
[0021]
With this configuration, it is possible to efficiently sort and record various real-time file data having different required bit rates on the recording area, so that the use efficiency of the recording area can be further improved. The advantage of this can be further achieved.
[0022]
The above and other objects and novel features of the present invention will become more fully apparent from the following description of the embodiments when read with reference to the accompanying drawings.
[0023]
“Block” in the claims of the present invention corresponds to “block” in the embodiment. A “unit” in the claims of the present invention corresponds to a “unit” in the embodiment. Further, the “block management table” in the claims of the present invention corresponds to the “block management table 210” in the embodiment. The “unit attribute table” in the claims of the present invention corresponds to the “unit management table 211” in the embodiment. Further, the “storage medium” in the claims of the present invention corresponds to “the hard disk drive 118 (hard disk built therein)” in the embodiment.
[0024]
However, the following embodiments are merely one embodiment of the present invention, and the meanings of the terms of the present invention and each component are not limited to those described in the following embodiments. Absent.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0026]
A. First embodiment
FIG. 1 is a block diagram showing an overall configuration of a digital recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, signal lines indicated by thick lines are signal lines indicating the flow of video and / or audio data, and signal lines indicated by thin lines are signal lines indicating the flow of control signals.
[0027]
The digital recording / reproducing apparatus includes an antenna 100, an external input terminal 101, tuners 102 and 103, a selector 104, A / D converters 105 and 106, MPEG2 video encoders 107 and 108, audio encoders 109 and 110, a multiplexer / demultiplexer 111, MPEG2 Video decoder 112, audio decoder 113, D / A converter 114, buffer memories 115 and 116, hard disk drive controller module 117, hard disk drive 118, system controller 119, memory 120, user interface 121, graphic controller 122, television monitor 123, Real-time clock module 124, digital input 125, digital And a Toputto 126, LED 127.
[0028]
Referring to FIG. 1, for example, a signal wave of a television broadcast received by antenna 100 is given to tuners 102 and 103 simultaneously.
[0029]
The tuner 102 selects a signal wave of one channel designated by the user from the signal waves received by the antenna 100, demodulates the signal wave into an analog television signal including a video signal and an audio signal, and inputs the signal to one input of the selector 104. Give to. The other input of the selector 104 is connected to an external input terminal 101 to which various external television signal sources such as a video tape recorder (VTR) and a camcorder can be connected.
[0030]
The selector 104 selects one of the output from the tuner 102 and the input from the external input terminal 101 and supplies the selected signal to the A / D converter 105 and also to one input of the graphic controller 122. Generally, the selector 104 selects the input from the external input terminal 101 when some external signal source is connected to the external input terminal 101, and selects the output of the tuner 102 when not connected.
[0031]
The A / D converter 105 converts the video signal and the audio signal of the analog television signal output from the selector 104 into digital signals, respectively, supplies the digital video signal to the MPEG2 video encoder 107, and converts the digital audio signal into an audio encoder. Give to 109.
[0032]
The MPEG2 video encoder 107 compresses the provided digital video signal and provides the same to the multiplexer / demultiplexer 111, and the audio encoder 109 compresses the provided digital audio signal and provides the same to the multiplexer / demultiplexer 111. The multiplexer / demultiplexer 111 multiplexes the supplied video signal stream and audio signal stream and converts them into an MPEG2 system stream.
[0033]
On the other hand, the tuner 103 selects a signal wave of one channel designated by the user from the signal waves received by the antenna 100, demodulates the signal wave into an analog television signal including a video signal and an audio signal, and performs A / D conversion. It is provided to the converter 106 and to another input of the graphic controller 122.
[0034]
The A / D converter 106 converts the video signal and the audio signal of the analog television signal output from the tuner 103 into digital signals, respectively, supplies the digital video signal to the MPEG2 video encoder 108, and converts the digital audio signal into an audio encoder. Give to 110.
[0035]
The MPEG2 video encoder 108 compresses the given digital video signal and provides it to the multiplexer / demultiplexer 111, and the audio encoder 110 compresses the given digital audio signal and provides it to the multiplexer / demultiplexer 111. The multiplexer / demultiplexer 111 multiplexes the supplied video signal stream and audio signal stream and converts them into an MPEG2 system stream.
[0036]
A hard disk drive (hereinafter, HDD) 118 having a built-in hard disk as an example of a randomly accessible storage medium is detachably attached to the digital recording / reproducing apparatus. In the following description, this single HDD 118 itself will be regarded as a writable and readable storage medium for convenience. The writing of data to the HDD 118 and the reading of data from the HDD 118 are executed by the HDD controller module 117 as described later.
[0037]
A first data bus including a buffer memory 115 in the middle and a second data bus including a buffer memory 116 in the middle are provided between the multiplexer / demultiplexer 111 and the HDD controller module 117. A system data channel is provided.
[0038]
Further, digital data from another device externally connected via a digital input 125 can be input to the buffer memory 115, while digital data from the buffer memory 116 can be input to another external device via a digital output 126. Can be output to other devices.
[0039]
Therefore, as will be described later, the exchange of the MPEG2 system stream data between the multiplexer / demultiplexer 111, the HDD controller module 117, the digital input 125 and the digital output 126 via the buffer memories 115 and 116. Will be done.
[0040]
The multiplexer / demultiplexer 111 demultiplexes the MPEG2 system stream received from the buffer memories 115 and 116 into a video signal stream and an audio signal stream, and outputs the former to the MPEG2 video decoder 112 and the latter to the audio decoder 113. Give to.
[0041]
The MPEG2 video decoder 112 decodes the supplied video signal stream and supplies it to the D / A converter 114, and the audio decoder 113 decodes the supplied audio signal stream and supplies it to the D / A converter 114. The D / A converter 114 converts the applied signals into analog signals, respectively, and supplies an analog television signal including a video signal and an audio signal to another input of the graphic controller 122.
[0042]
The graphic controller 122 selects one of the analog television signals supplied from the selector 104, the tuner 103, and the D / A converter 114, and selects a television monitor connected to the outside of the digital recording / reproducing apparatus. Give to 123.
[0043]
The operations of the multiplexer / demultiplexer 111 and the graphic controller 122 are controlled by control signals provided from the system controller 120.
[0044]
When this digital recording / reproducing apparatus is connected to another external apparatus via a digital input 125 and a digital output 126, a control signal from the system controller 119 is transmitted via the digital input 125 to another thin line. The control signal is supplied to a system controller (not shown) of the apparatus, and a control signal from the system controller is supplied to the system controller 119 of the digital recording / reproducing apparatus via a digital output 126 (thin line).
[0045]
A user interface 121, a memory 120, and a real-time clock module 124 are connected to the system controller 119.
[0046]
The basic operation principle of the digital recording / reproducing apparatus according to the present invention shown in FIG. 1 such as storage, reproduction, and erasure will be described later in detail in relation to a file storage method for the hard disk drive 118.
[0047]
Next, information stored in a hard disk as a storage medium in the present embodiment will be described.
[0048]
As shown in FIG. 2, when data is stored as a file on a hard disk serving as a storage medium, data to be stored such as video and audio (hereinafter referred to as main data 20) and the main data 20 are configured as a file. Necessary management information (hereinafter referred to as metadata 21) is stored in the hard disk.
[0049]
The metadata 21 is composed of three pieces of information: a block management table 210, a unit management table 211, and file management information 212. In the digital recording / reproducing apparatus, the metadata 21 is generated at the time of initial setting of a storage medium, and each time data is recorded or erased. Will be updated to
[0050]
Hereinafter, each of the management information will be described with reference to FIG.
[0051]
FIG. 3 is a diagram schematically illustrating a recording method using a unit management table.
[0052]
<Block management table>
The block management table 210 manages the use status of each block. The entries 210a, 210b, 210c, 210d,... Constituting the block management table 210 correspond to the blocks of the storage areas 30a, 30b, 30c, 30d,. In this case, "1" is shown, and in the case of an unused block, "0" is shown.
[0053]
<Unit management table>
The unit management table 211 manages the use state of each unit when the storage area of the HDD 118 is regarded as an address space in units and numbered in order.
[0054]
The unit is composed of entries 211a, 211b,... For example, the entry 211a is an entry of a unit corresponding to the entries 210a, 210b, 210c, 210d on the block management table 210. The unit management table 211 shows unit status information indicating whether or not a real-time file can be stored for the unit, and unit usage status information indicating the usage status of the unit.
[0055]
Here, whether or not a real-time file can be stored in the unit is determined, for example, by monitoring a storage / reproduction operation by a special command for executing read / write, similarly to the determination in the second embodiment described later, in real time. This is done by determining whether storage / reproduction is guaranteed.
[0056]
The unit status information and the unit use status information of each unit are divided as shown in FIG. In the unit use status information, “unused” refers to a state in which all blocks constituting the unit can be stored. The “RT full use” refers to a state in which all blocks constituting the unit are continuously used for storing a real-time file. Further, "partially using the NRT" means a state in which a part of the blocks constituting the unit is used for storing a non-real-time file. “All use of NRT” means a state in which all the blocks constituting the unit are used for storing the non-real-time file.
[0057]
Since the unit has a size necessary for real-time processing, there is no state where the unit is partially used by the real-time file. Also, neither real-time file nor non-real-time file exists in the unit. Therefore, when the unit is "partially used for NRT", only the non-real-time file can be stored in the remaining blocks.
[0058]
<File management information>
Returning to FIG. 2, the file management information 212 is management information for the main data 20 to be recognized as a file.
[0059]
In the file management information 212 of the file corresponding to the main data 20, link information of blocks constituting the main data 20 is recorded. Specifically, attribute information (not shown in the figure) regarding the main data 20 and start address information of the block are stored in the order of reference.
[0060]
The attribute information includes information indicating whether the main data 20 is data to be processed in real time.
[0061]
In the real-time file 201 (see FIG. 3), main data 20 to be processed in real time, such as an MPEG2 system stream created by the multiplexer / demultiplexer 111, is stored as the above-described unit data.
[0062]
Therefore, the total capacity of the real-time file 201 is always an integral multiple of the unit capacity. Also, in the HDD 118 that performs recording in block units, the start address of the real-time file 201 must be an address corresponding to a unit boundary. This is because in the unit management table 211, the storage space is regarded as an address space for each unit.
[0063]
The file management information 212 indicating the file configuration of the real-time file 201 stores link information of a block corresponding to the unit to which the real-time file 201 is assigned.
[0064]
In the case of the non-real-time file 202, since the main data 20 that does not need to be processed in real time is stored as data in block units, the total capacity of the non-real-time file 201 is an integral multiple of the block unit capacity.
[0065]
The file management information 212 indicating the file configuration of the non-real-time file 202 stores link information of a block to which the non-real-time file 202 is allocated, similarly to the real-time file.
[0066]
<Unit capacity>
Next, a description will be given of the capacity of a unit required for simultaneously handling a plurality of stream data in real time in the digital recording / reproducing apparatus.
[0067]
First, the capacity C of the buffer memories 115 and 116, the unit block length L of writing / reading, the worst case data transfer rate Bhdd between the HDD controller module 117 and the HDD 118, the rate Bsys of the MPEG2 system stream, and the HDD 118 Of the seek time with the worst value Tw will be described.
[0068]
However, the worst value Tw of the seek time is not the time required only for the seek of the head but the seek time, the rotation waiting time, and the head switching time required from the start of the seek to the actual start of data writing / reading. , The time required for error correction such as ECC / EDC, etc., and the time considering all worst values of group delay.
[0069]
Assuming that the number of streams to be processed simultaneously is N, the following equation must be satisfied in order to maintain the real-time properties of all the streams.
Bhdd × Ts> N × (Tw + Ts) × Bsys (1)
[0070]
Here, Ts is a time required for writing / reading the unit block length L of writing / reading to / from the HDD 118, and is represented by Ts = L / Bhdd.
[0071]
In the above equation (1), in the case of data reading, the amount of data read in a unit block in a certain stream is determined by the N seek times and the N data writes required to process N streams. This means that it is necessary to design so as not to be consumed within the sum of the time and the read time.
[0072]
Further, in the case of writing data, the amount of data stored in the buffer memories 115 and 116 during the time required to process N streams should be N × (Tw + Ts) × Bsys in the worst case. Means
[0073]
Therefore, the capacity C of the buffer memories 115 and 116 needs to satisfy the following equation.
C> N × (Tw + Ts) × Bsys (2)
[0074]
By performing a design that satisfies the above equations (1) and (2), it becomes possible to simultaneously process N streams in real time. However, N must be set within a range that satisfies Bhdd> N × Bsys.
[0075]
When data of a real-time file is transferred from the HDD 118 to the buffer memories 115 and 116, processing can be performed most efficiently by reading the data in units. At this time, the unit capacity Usize can be expressed by the following equation.
Usize = L ... (3)
[0076]
Here, as described above, since Ts = L / Bhdd, the following equation can be obtained as a conditional equation for the Usize capacity by substituting this relational equation and equation (3) into equation (1).
Usize> N × (Tw + (Usize / Bhdd)) × Bsys (4)
[0077]
Video data and audio data for a certain period of time are stored in a unit having this capacity. In the apparatus of this embodiment, MPEG-2 encoded video data (Group of Pictures: GOP) and corresponding audio data are multiplexed by a multiplexer / demultiplexer 111 to form a system stream.
[0078]
If the number of pictures in one GOP is 15, the reproduction time of one unit is as follows.
5 * (15/30) = 2.5 seconds
[0079]
Here, it is verified whether or not reproduction of each of these parameters is guaranteed in units.
[0080]
From the above definition, if the unit length of writing / reading is L = 27552512 bytes, the rate Bsys of the MPEG2 system stream is
Bsys = L / 2.5 = 1110004 bytes / second
It becomes.
[0081]
In this digital recording / reproducing apparatus, assuming that the number of streams is N = 2, the worst value of the seek time is Tw = 50 ms, and the worst case data transfer rate between the HDD controller module 118 and the HDD 119 is Bhdd = 5 MB / sec. ,
Ts = L / Bhdd = 550ms
Holds. Therefore, the left side Bhdd * Ts of the equation (1) is
Bhdd * Ts = 5 × 10⁶* 550 × 10^-3= 2.7 × 10⁶
The right side N * (Tw + Ts) * Bsys of the equation (1) is
N * (Tw + Ts) * Bsys = 2 * (50 + 550) × 10^-3* 1101004 = 1.32 × 10-⁶
Which satisfies the above equation (1). Therefore, reproduction of data in units of units is guaranteed with these defined parameters.
[0082]
Next, file read (read) and write (write) operations will be described with reference to flowcharts.
[0083]
FIG. 4 is a flowchart illustrating a file data read operation.
[0084]
First, when a file is opened by an application (step S1), file management information of the file is read, and link information in the file management information is referred to. As described above, the link information specifies the start address of each block that stores the file information in the reference order. The reading of the file information is performed by referring to the link information in order from the beginning, acquiring the start address of each block, and sequentially reading data from the block on the storage area indicated by the acquired start address. Here, the reference position of the link information is managed by a pointer.
[0085]
First, a pointer is set at the head of this link information (step S2), and the start address of the first block storing the file information is obtained. Then, data is read from the block on the storage area indicated by the start address (step S3).
[0086]
Next, it is determined whether or not this block is the last logical block constituting the file (step S4). If it is the last, the file is closed (step S5), and the read operation is terminated. On the other hand, if there is a block that follows the logical block constituting the file rather than the last block, the pointer indicating the reference position of the link information is advanced by one (step S2), and the next block storing the file information is advanced. Is obtained. Then, data is read from the block on the storage area indicated by the block start address (step S3).
[0087]
The above data reading is repeated until it is determined in step S4 that the block indicated by the pointer is the last block. Thereby, all the file information is read from the storage medium.
[0088]
FIG. 5 is a flowchart illustrating a write operation of a real-time file.
[0089]
When the application opens the real-time file (step S11), first, an unused unit is searched with reference to the unit management table 211 (step S12).
[0090]
The unused unit obtained as a result of the search is newly assigned to a unit for storing a file, and the main data 20 to be stored is sequentially stored in a series of blocks corresponding to the unit. At this time, the unit use status information in the unit management table 211 corresponding to the unit used for storage is changed from “unused” to “RT all used”. Further, the block management table 211 is updated so that the flag of the block used for storage is changed to “1”. Further, link information of each block used for recording is added to the file management information 212 (step S13).
[0091]
Next, it is determined whether or not data to be stored remains (step S14). If there is no data to be stored, the file is closed (step S15), and the process ends. On the other hand, if data to be stored remains, an unused unit is further searched (step S12). Then, the data is stored in the unit obtained by the search (step S13). The above data storage processing is repeated until it is determined in step S14 that there is no data to be stored.
[0092]
FIG. 6 is a flowchart illustrating a non-real-time file write operation.
[0093]
When the application opens the non-real-time file (step S21), first, the unit management table 211 is searched for whether or not an NRT partially used unit exists (step S22). If there is no NRT partially used unit as a result of the search, an unused unit is searched again by referring to the unit management table 211 (step S24). Then, the block corresponding to the obtained unused unit is allocated as a block for storing the main data 20.
[0094]
Further, the unit use status information of the unit management table 211 corresponding to the unit used for storage is changed from “unused” to “partially used NRT” (step S25).
[0095]
On the other hand, if there is an NRT partially used unit as a result of the search in step S22, an unused block in the obtained NRT partially used unit is allocated as a block for storing main data 20 (step S23). . Here, when all the unused blocks in the NRT partially used unit are used by storage, the unit usage status information of this unit is changed from “NRT partially used” to “NRT fully used”.
[0096]
Then, the main data 20 is stored in the unused block allocated in step S23 or S24, and the block management table 210 is updated so that the flag of the block used for storage is changed to “1”. Further, link information of the block used for storage is added to the file management information 212 (step S26).
[0097]
Next, it is determined whether or not data to be stored remains (step S27). If there is no data to be stored, the file is closed (step S28), and the process ends. On the other hand, if there is data to be stored, an unused unit and an unused block are further searched, and the process of storing data in the block obtained by the search (steps S22 to S26) is repeated.
[0098]
FIG. 7 is a flowchart illustrating a real-time file deletion operation.
[0099]
When the application selects a real-time file to be deleted (step S31), the first block among the blocks storing the selected real-time file is obtained with reference to the link information of the file management information 212. Further, a unit corresponding to the block is calculated from the unit size information in the unit management table 211 (step S32). Then, the data stored in this block is sequentially erased.
[0100]
When the data stored in the block is erased in this way, the block management table 210 indicating the use status of the block changes from “1” indicating that the block is being used to “0” indicating that it is not used. Is changed to Further, when data is erased for all blocks in one unit, the unit use status information in the unit management table 211 indicating the use status of this unit is changed from "RT all use" to "unused" (step). S33).
[0101]
Then, it is determined whether or not data to be deleted remains (step S34). If there is no data to be deleted, the management information of this file is deleted from the file management information 212 (step S35), and the processing is performed. Is terminated.
[0102]
On the other hand, if data to be deleted remains, the pointer to the link information of the file management information 212 is advanced by one, the next block is obtained, and the block corresponding to the block is obtained from the unit size information in the unit management table 211. A unit is calculated (step S32). Then, similarly to the above, the block management table 210 and the unit management table 211 are updated (step S33). This updating process (steps S32 and S33) is repeated until it is determined in step S34 that there is no data to be deleted.
[0103]
FIG. 8 is a flowchart illustrating the operation of deleting a non-real-time file.
[0104]
When the application selects a non-real-time file to be deleted (step S41), the first block among the blocks storing the selected non-real-time file is acquired with reference to the link information of the file management information 212.
[0105]
Next, the block management table 210 indicating the use status of this block is changed from “1” indicating that the block is being used to “0” indicating that it is not used (step S43). Further, the use status of other blocks included in the unit corresponding to this block is checked (step S44), and when all the blocks constituting the unit are unused, unit management indicating the use status of this unit is performed. The unit use status information in the table 211 is changed to "unused" (step S46).
[0106]
When a part of the block constituting the unit is used, the unit use status information of the unit management table 211 indicating the use status of the unit is changed to “NRT partial use”. (Step S45).
[0107]
Next, it is determined whether or not data to be deleted remains (step S47). If the result of the determination is that there is no data to be deleted, the management information of this file is deleted from the file management information 212 ( Step S48), the process ends. On the other hand, when data to be deleted remains, the pointer indicating the link information of the file management information 212 is advanced by one, and the next block is obtained (step S42). Then, similarly to the above, the block management table 210 and the unit management table 211 are updated (steps S43 to S46). This updating process (steps S42 to S46) is repeated until it is determined in step S47 that there is no data to be deleted.
[0108]
FIG. 9 is a flowchart illustrating the initialization operation of the storage medium.
[0109]
When a storage medium is used for the first time in the present apparatus, the management data used for managing the storage area, specifically, the block management table 210 in the metadata 21, the unit, so that the storage medium can be used in the present apparatus. A management table 211 is generated, and initial settings are made.
[0110]
The application specifies the capacity of the unit and the number of units, and the unit management table 211 is initialized according to the application (step S51).
[0111]
In the block management table 210, “0” is set to “unused” for all blocks (step S52).
[0112]
In the unit management table 211, “RT usable unit” indicating that a real-time file can be stored is set as status information for all units, and all units constituting the unit are used as unit usage status. Is set to "unused" indicating that the can be stored (step S52).
[0113]
As described above, in the present embodiment, when managing the storage location of the main data in the storage medium, in addition to the block depending on the physical storage unit used in the conventional file storage method, it is processed in real time. A unit that is a recording unit suitable for storing data to be stored is used.
[0114]
This unit is set to a capacity that guarantees real-time processing, and is composed of a plurality of continuous blocks. Units and blocks are uniquely associated with each other by calculation using unit size information in the unit management table. Even if a real-time file such as video data stored in step (1) is stored in units, the file data can be read out in blocks by using only the block management table 210 without making the unit management table 211 essential.
[0115]
In addition, for data processed in a non-real time manner, data is stored in block units as in the conventional case, but the unit management table is also updated in accordance with the block usage status at this time.
[0116]
As described above, by changing the storage unit according to the attribute of the data, the storage medium can be used efficiently, and the occurrence of fragmentation of the storage area can be suppressed.
[0117]
B. Second embodiment
By the way, in the above embodiment, the unit management table defines only two types of units, “RT usable unit” and “RT unusable unit”, according to whether the unit is used or not used. . However, while data recording / erasing is repeated, a defect area occurs which cannot be compensated by error correction. As a result, even if the unit is unused, there may be a case where the unit cannot be used for storing and reproducing the real-time file.
[0118]
That is, a storage area such as a hard disk is usually provided with an alternative area in order to cope with the occurrence of a defective area. When a defective area occurs, data is allocated to the substitute area.
[0119]
However, the replacement area is usually physically separated from the series of storage areas. Therefore, when data is stored in the alternative area, extra time such as seek and rotation is required during storage and reproduction. Therefore, even if a unit is in an unused state, if a defective area exists in the unit, a write / read rate necessary for storage / reproduction of a real-time file may not be guaranteed. For this reason, even if the unit is unused, if a defective area occurs, the unit may not be used as it is as an RT usable unit.
[0120]
On the other hand, for example, in digital broadcasting, the bit rate for HD (High Definition) broadcasting is about 24 Mbps, and the bit rate for SD (Standard Definition) broadcasting is about 8 Mbps. Therefore, when a defective area occurs in a predetermined unit, even if the unit cannot be used for HD broadcasting, it may be usable for SD broadcasting at a lower rate. For this reason, even if the writing / reading rate of a unit is reduced due to the occurrence of a defective area, it is not appropriate to make the unit "RT unusable" uniformly.
[0121]
Therefore, in the present embodiment, a rank division of the write / read rate is assigned to each unit, and this rank division is included in the unit management table. Then, when writing a real-time file, a unit that can guarantee the transfer rate of the file is selected as a target unit by referring to the rank division.
[0122]
Each unit is initially ranked at the highest rate rank. Then, at the time of subsequent writing / reading, it is determined whether or not the transfer rate of the real-time file can be guaranteed. If the transfer rate cannot be guaranteed here, the rank is changed to a rank lower than the transfer rate of the file.
[0123]
Whether or not the transfer rate of the real-time file can be guaranteed is determined using, for example, a special command used when an HDD (hard disk drive) is used for AV data storage. This command is a command for emphasizing real-time property, and is a command for executing time-limited read and write.
[0124]
<Read / write command with time limit>
The definition of time here is that the HDD always returns a response to the host within the specified time. When these commands are used, the processing priority on the HDD side is as follows.
[0125]
1. Completes input / output of data normally within the specified time and notifies the host.
2. When an error occurs in the middle and a retry or alternative processing is required;
If it can be processed within the specified time, execute it. If the time exceeds the specified time, the error is ignored, the input / output processing for the specified number of sectors is completed within the specified time, and the host is notified. In this case, the host is notified in the form of "error occurred but input / output completed", and error information is recorded in a log.
3. When the I / O processing does not end even if the generated error is ignored;
Interrupt the processing within the specified time and notify the host in the form of a "time-out error". Originally, it is assumed that a response is returned within the specified time. However, as an exception, read / write is performed at least once, and no response is made within the specified time only when the specified time is already exceeded at this point. It is fine. However, it is necessary to notify the host that "the specified time is over".
[0126]
As described above, when the unit on the storage medium of the HDD has a defect, the real-time property in data access of the part is reduced. Therefore, if the unit status information for each unit is provided with a rank division of the bit rate that can be guaranteed by the unit, by referring to this, data of various bit rates are allocated to the appropriate units, thereby real-time In addition, it is possible to realize storage that guarantees the performance and effectively uses the storage medium.
[0127]
Hereinafter, a more specific configuration and control of such an embodiment will be described.
[0128]
<Replacement of media>
When there is a defect on the medium of the HDD which is a storage medium, a replacement block is usually assigned.
[0129]
In the case of an optical disk or the like, the position, the number, and the like of the substitute blocks are determined as standards, but in the case of an HDD, only the command interface is defined, and the internal structure differs for each drive vendor. Therefore, the substitution processing sequence, the substitution block position, the overhead time when reading and writing the substitution block, and the like are not specified. This poses a problem in real-time processing, and will be described below.
[0130]
<Relationship between physical address and logical address and fragmentation>
FIG. 13 shows a relationship among a physical address, a logical address, and a defective block management list on a medium. Hereinafter, the processing procedure of a defective block and the accompanying fragmentation will be described.
[0131]
When a hard disk is taken as an example, usually, at the start of use, the continuity of the logical address accessed from the host may be considered to be the continuity of the physical address on the medium. Originally, defective sectors already existing at the time of product shipment are replaced at the time of shipment, but are omitted here for simplicity.
[0132]
A substitute block for a late defective block is prepared on the disk. In the case of a hard disk, its number and physical position are not specified, and, for example, a substitute block area is arranged on the innermost circumference of the disk. Naturally, there is no mapping to a logical address for this area.
[0133]
As shown in FIG. 13, for example, when the logical block A is determined to be a defective block, the drive remaps the physical block A corresponding to the logical block A to the substitute block B + 1. That information is registered in the defect list.
[0134]
As described above, when the replacement processing of the defective block is performed, in the unit corresponding to the block in which the replacement processing is performed, even though the logical address is continuous, the logical block A is physically non-consecutive. State, and seek occurs before and after the block. This is a cause that is fatal for real-time processing.
[0135]
<Correlation between real-time guarantee of AV stream and alternative processing>
The following is an example of real-time processing of an AV stream.
[0136]
Assuming that the worst case transfer rate a (MB / s), the worst case (seek time + rotation waiting time) b (sec), the unit size c (MB), and the AV stream bit rate d (MB / s),
The worst case unit access (read / write) time is
y = c / a (sec),
The playback time of an AV stream in units of
z = c / d (sec)
It becomes.
[0137]
The relationship in the real-time processing of one AV stream is as follows.
y + b <z, that is, y <z−b
[0138]
The relationship in the real-time processing of two AV streams is as follows.
2 * (y + b) <z, that is, y <z / 2−b
[0139]
The relationship in real-time processing when n units of a unit are arranged in a substitute block in one AV stream is as follows.
y + (n + 1) b <z, that is, y <z− (n + 1) b
[0140]
In a unit alternately accessed by two AV streams, a relationship in real-time processing in a case where a total of n locations are arranged in a substitute block in any two units continuously accessed is as follows.
2y + (n + 2) b <z, that is, y <z / 2− (n + 2) b / 2
[0141]
As described above, the greater the number of alternative processes, the longer the unit access time. Then, when the threshold value is exceeded, the real-time property is broken.
[0142]
Therefore, it is necessary to disable a unit at a certain point where the number of replacement blocks increases.
[0143]
<Unit management table>
The unit management table 211 manages the use state of each unit when the storage area of the HDD 118 is regarded as an address space in units and numbered in order.
[0144]
As shown in FIG. 3, the unit is composed of entries 211a, 211b,... For example, the entry 211a is an entry of a unit corresponding to the entries 210a, 210b, 210c, 210d on the block management table 210. The unit management table 211 defines unit status information indicating whether or not a real-time file can be stored for the unit, and unit usage information indicating the usage status of the unit.
[0145]
The unit status information and the unit use status information of each unit are divided as shown in FIG.
[0146]
As in the first embodiment, the unit usage status information indicates four statuses of “RT full use”, “unused”, “NRT partial use”, and “NRT full use”.
[0147]
The unit status information indicates either “RT usable unit” or “RT unusable unit”. Here, the “RT usable unit” refers to a state in which real-time information can be recorded. The "RT unusable unit" refers to a state in which real-time information cannot be recorded.
[0148]
The “RT usable unit” further includes, for example, “a unit usable in an RT stream up to 30 Mbps”, “a unit usable in an RT stream up to 15 Mbps”, and an “RT stream up to 5 Mbps” depending on the bit rate of the real-time stream. It is divided into three stages of "usable unit".
[0149]
As described above, for example, in digital broadcasting, the bit rate for HD broadcasting is about 24 Mbps, and the bit rate for SD broadcasting is about 8 Mbps. In this case, a unit that cannot be used for storing an HD broadcast program may be usable for storing an SD broadcast program. When recording an analog broadcast, three different bit rates, for example, a high-quality recording mode of 10 Mbps, a standard recording mode of 6 Mbps, and a long-time recording mode of 3 Mbps are assumed. Also in this case, a unit that cannot be used in the high-quality recording mode may be usable in the standard recording mode or the long-time recording mode.
[0150]
The unit is an area that can be continuously recorded on the physical medium, but when a defective block is found, the block is reallocated to an alternative area. In this case, even if it is logically continuous, physically, a boundary occurs there, and seek and rotation wait time is required. This can be fatal to real-time processing in some cases.
[0151]
Therefore, in the initial state, the unit can be used at the highest bit rate rank as real-time processing, but as the use continues, the bit rate supported by the unit changes, so whether the system side can be used or not. Is checked, and if it is determined that it cannot be used, it is necessary to disable real-time information recording.
[0152]
The check on the system side can be executed, for example, by performing a read or write in a unit unit using a time-limited command with the above-mentioned time limit. The parameter of the time limit is a limit time during which the real-time processing does not fail according to the bit rate.
[0153]
By using this command, a unit whose time limit has been exceeded is unavailable at that bit rate, and the rank of the bit rate is set to a rank lower than the bit rate of the command.
[0154]
Here, the bit rate of the command is obtained by dividing the data size to be read and written by the command by the time limit. A unit that cannot be used even at the lowest bit rate is regarded as a unit that cannot record real-time information.
[0155]
FIG. 11 is a flowchart illustrating a file read operation according to the second embodiment.
[0156]
First, when a file is opened by an application (step S61), the link information stored in the file management information 212 of the file is referred to. At this time, the reference position of the link information is managed using the pointer. The block start address is obtained from the link information at the position indicated by the pointer, and data is read from the block on the storage area indicated by the block start address by a time-limited AV command (step S62).
[0157]
Next, it is determined whether or not “specified time over” has occurred by the read command with time limitation (step S63). As a result, when an “over time” error occurs, the corresponding bit rate rank in the unit status information of the unit management table 211 corresponding to the used unit is changed to a rank lower than the bit rate of this command. (Step S64).
[0158]
Then, it is determined whether or not the block being read is the last logical block constituting the file (step S65). If it is the last, the file is closed (step S66), and the read operation is terminated.
[0159]
If there is a block in which the block being read is not the last block of the logical block constituting the file, the pointer indicating the reference position of the link information is advanced by one, and the block start address is obtained from the next link information. Data is read from the block on the storage area indicated by the block start address (step S62). This reading process (steps S62 to S64) is repeated until it is determined in step S65 that the block being read is the last block.
[0160]
FIG. 12 is a flowchart illustrating a real-time file write operation according to the second embodiment.
[0161]
When the application opens the real-time file (step S71), first, the unit management table 211 is searched for an unused unit that can be used at the write bit rate. (Step S72).
[0162]
The unit obtained as a result of the search is newly assigned to a unit for storing a file, and the main data 20 to be stored is stored in a series of blocks corresponding to the unit by a time-limited write command. At this time, the unit use status information in the unit management table 211 corresponding to the unit used for storage is changed from “unused” to “RT all used”. Further, the block management table 211 is updated so that the flag of the block used for storage is changed to “1”. Further, link information of each block used for recording is added to the file management information 212 (step S73).
[0163]
Next, it is determined whether or not "specified time over" has occurred by the time-limited write command in step S73 (step S74). As a result, when an “over time” error occurs, the corresponding bit rate rank in the unit status information of the unit management table 211 corresponding to the used unit is changed to a rank lower than the bit rate of the command ( Step S75).
[0164]
Next, it is determined whether or not data to be stored remains (step S76). If there is no data to be stored, the file is closed (step S77), and the process ends. On the other hand, when data to be stored remains, the processing from step S72 is further repeated.
[0165]
In a read operation and a write operation, assuming that there is no read error or write error, respectively, if a "time limit exceeded" error occurs in a time-limited command, it may be determined that the block is already in a fragmented state. it can. Therefore, in this case, the corresponding bit rate rank in the unit status information is set to a rank lower than the bit rate of the command.
[0166]
The operation for initializing the storage medium according to the second embodiment is performed in the same manner as the operation for initializing the storage medium according to the first embodiment (FIG. 9). Here, in step S52, "RT usable unit (up to bit rate aMbps)" indicating that a real-time file having the highest bit rate can be stored is further set as the state information.
[0167]
As described above, according to the present embodiment, similarly to the first embodiment, in addition to the merit that the real-time file and the non-real-time file can be written smoothly and efficiently, there is a further demand. Various real-time file data having different bit rates can be efficiently sorted and recorded on the same HDD, and therefore, there is an advantage that the usage efficiency of the HDD can be further improved.
[0168]
It is needless to say that the present invention is not limited to the above embodiment. In the above-described embodiment, a digital recording / reproducing apparatus for recording / reproducing MPEG data has been described as an example. However, a digital recording / reproducing apparatus for recording / reproducing only audio data or recording / reproducing data obtained via the Internet may be used. It can be widely used for recording and playback devices.
[0169]
The programs for generating the various management tables shown in FIGS. 2 and 10 and for executing the processes shown in FIGS. 4 to 9, 11 and 12 are the same as those in the form preinstalled in the HDD control module 117. , Or from a storage medium such as a CD-ROM, or from an application server via the Internet.
[0170]
In addition, the update timing of the metadata, the configuration timing of the metadata file, and the like can be appropriately changed.
[0171]
【The invention's effect】
According to the file recording management method of the present invention, it is possible to perform file allocation suitable for reproducing a real-time file, and to suppress the occurrence of fragmentation of a storage area due to small-sized data, thereby improving the use efficiency of the storage area. Can be done.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a recording / reproducing apparatus according to a first embodiment.
FIG. 2 is a view showing the structure of recording information according to the first embodiment;
FIG. 3 is a diagram schematically showing a recording method according to the first embodiment.
FIG. 4 is a flowchart of a read operation according to the first embodiment;
FIG. 5 is a flowchart of a write operation according to the first embodiment;
FIG. 6 is a flowchart of a write operation according to the first embodiment;
FIG. 7 is a flowchart of a deletion operation according to the first embodiment.
FIG. 8 is a flowchart of a deletion operation according to the first embodiment.
FIG. 9 is a flowchart of an operation of initializing the storage medium according to the first embodiment;
FIG. 10 is a diagram showing a structure of recording information according to a second embodiment.
FIG. 11 is a flowchart of a read operation according to the second embodiment;
FIG. 12 is a flowchart of a write operation according to the second embodiment.
FIG. 13 is a diagram showing a relationship among a physical address, a logical address, and a defective sector list on a medium.
FIG. 14 is a diagram showing a file configuration in a conventional file recording method.
FIG. 15 is a diagram showing a file configuration in a conventional file recording method.
[Explanation of symbols]
30, 30a-30d block
201 @ Real-time file 1
202 @ Non-real-time file 2
210 block management table
210a to 210d Entry in block management table
211 Unit management table
211a, 211b @ Unit management table entry

Claims (24)

A file data storage management method for storing file data in a storage area divided into a plurality of blocks,
A file data storage management method characterized by storing file data based on a unit attribute table for managing attributes of a unit composed of a plurality of continuous blocks. 2. The device according to claim 1, further comprising a block management table for managing whether data is stored in the block,
The unit attribute table includes a use status of each unit and information that specifies whether real-time data can be stored,
The data storage processing includes:
If the stored file data is real-time data, the unit attribute table is referred to, an unused unit capable of storing the real-time data is searched, and the file data is stored in the block included in the searched unit. And
When the stored file data is non-real-time data, the unit attribute table is searched for a unit in which non-real-time data is already stored in some blocks in the unit, and the unit is obtained by this search. And storing the file data in unused blocks included in the unit. In claim 2,
In the data storage processing, when file data to be stored is non-real-time data, a unit in which non-real-time data is already stored in some blocks in the unit cannot be acquired by referring to the unit attribute table. File data storage management, comprising: searching for an unused unit by referring to the unit attribute table; and storing the file data in the block included in the unit obtained by the search. Method. 4. The unit attribute table according to claim 2, wherein the unit attribute table further includes information defining a rank of a write and / or read rate for each unit,
When the file data to be stored is real-time data, the data storage processing refers to the unit attribute table to search for an unused unit that satisfies a write and / or read rate required for the file data. And storing the file data in the block included in the searched unit. 5. The rank of the write / read rate of the unit according to claim 4, wherein when writing or reading the file data, writing or reading to or from the unit cannot be performed at a writing and / or reading rate required for the file data. And a rate rank changing process for changing the rank of the file data to a rank lower than the rank of the write / read rate requested for the file data. 6. The file data storage management method according to claim 2, further comprising a link table that defines a link of a block used for storing the file data for each file data. The capacity Usize of the unit according to any one of claims 2 to 6,
Usize> N × (Tw + (Usize / Bhdd)) × Bsys,
(However, the minimum data transfer rate Bhdd with respect to the storage device means, the bit rate Bsys of the data stream, the worst value Tw of the seek time in the storage means, and the number of streams to be simultaneously processed are N). File data storage management method. A file data storage device that stores file data in a storage area divided into a plurality of blocks,
Means for generating a block management table for managing whether data is stored in the block,
Means for generating a unit attribute table for managing attributes of a unit composed of a plurality of continuous blocks,
Means for storing file data based on the unit attribute table,
The unit attribute table includes a use status of each unit and information that specifies whether real-time data can be stored,
The means for storing the data comprises:
If the stored file data is real-time data, the unit attribute table is referred to, an unused unit capable of storing the real-time data is searched, and the file data is stored in the block included in the searched unit. And
When the stored file data is non-real-time data, the unit attribute table is searched for a unit in which non-real-time data is already stored in some blocks in the unit, and the unit is obtained by this search. A file data storage device for storing the file data in unused blocks included in the unit. In claim 8,
When the file data to be stored is non-real-time data, the unit for storing the data refers to the unit attribute table, and the non-real-time data is already stored in some blocks in the unit. When a unit cannot be obtained, an unused unit is searched by referring to the unit attribute table, and the file data is stored in the block included in the unit obtained by the search. apparatus. 10. The unit attribute table according to claim 8 or 9, wherein the unit attribute table further includes information defining a rank of a write and / or read rate for each unit,
The means for storing the data, when the file data to be stored is real-time data, refers to the unit attribute table, and stores the unused unused data satisfying the write and / or read rate required for the file data. A file data storage device which searches for a unit and stores the file data in the block included in the searched unit. 11. The rank of the write / read rate of the unit according to claim 10, wherein, when writing or reading the file data, if writing or reading to or from the unit cannot be performed at a writing and / or reading rate required for the file data. File data storage device, further comprising means for executing a process of changing the rank of the file data to a rank lower than the rank of the write / read rate requested for the file data. The file data storage device according to any one of claims 8 to 11, further comprising means for generating a link table that specifies a link of a block used for storing the file data for each file data. The capacity Usize of the unit according to any one of claims 8 to 12,
Usize> N × (Tw + (Usize / Bhdd)) × Bsys,
(However, the minimum data transfer rate Bhdd with respect to the storage device means, the bit rate Bsys of the data stream, the worst value Tw of the seek time in the storage means, and the number of streams to be simultaneously processed are N). File data storage device. A program for executing a process for storing file data in a storage area divided into a plurality of blocks,
Constructing a unit from a plurality of continuous blocks, and generating a unit attribute table for managing attributes of each unit;
Storing a file data based on the unit attribute table. 15. The method according to claim 14, further comprising: generating a block management table for managing whether data is stored in the block.
The unit attribute table includes a use status of each unit and information that specifies whether real-time data can be stored,
The data storage step includes:
If the stored file data is real-time data, the unit attribute table is referred to, an unused unit capable of storing the real-time data is searched, and the file data is stored in the block included in the searched unit. And
When the stored file data is non-real-time data, the unit attribute table is searched for a unit in which non-real-time data is already stored in some blocks in the unit, and the unit is obtained by this search. A step of storing the file data in an unused block included in the unit. 16. The data storage step according to claim 15, wherein when the stored file data is non-real-time data, the non-real-time data is already stored in some blocks in the unit with reference to the unit attribute table. When the unit cannot be acquired, the unit attribute table is searched for an unused unit by referring to the unit attribute table, and the file data is stored in the block included in the unit acquired by the search. Program to do. 17. The unit attribute table according to claim 15, wherein the unit attribute table further includes information defining a rank of a write and / or read rate for each unit,
When the file data to be stored is real-time data, the data storage step refers to the unit attribute table to search for an unused unit that satisfies a write and / or read rate required for the file data. And storing the file data in the block included in the searched unit. 18. The rank of the write / read rate of the unit according to claim 17, wherein when writing or reading the file data, writing or reading to or from the unit cannot be performed at a writing and / or reading rate required for the file data. The program further comprises a rate rank changing step of changing the file rank to a rank lower than the rank of the write / read rate requested for the file data. 19. The program according to claim 15, further comprising a step of generating a link table that specifies a link of a block used for storing the file data for each file data. 20. The unit according to claim 15, wherein a capacity Usize of the unit is:
Usize> N × (Tw + (Usize / Bhdd)) × Bsys,
(However, the minimum data transfer rate Bhdd with respect to the storage device means, the bit rate Bsys of the data stream, the worst value Tw of the seek time in the storage means, and the number of streams to be simultaneously processed are N). Program to do. A storage medium in which file data is stored in a storage area divided into a plurality of blocks,
A block management table that manages whether data is stored in the block,
A storage medium storing a unit attribute table for managing attributes of a unit formed of a plurality of continuous blocks. 22. The storage medium according to claim 21, wherein the unit attribute table includes a use status of each unit and information specifying whether real-time data can be stored. 23. The storage medium according to claim 22, wherein the unit attribute table further includes information defining a rank of a writing and / or reading rate for each unit. 24. The storage medium according to claim 22, wherein the storage medium further stores a link table that specifies a link of a block used for storing the file data for each file data.

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