JP2000227865A - Device and method for recording and reproducing information for segment cache system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate a processing speed at the time of read and write by improving the use efficiency of a cache memory by setting a cache area to a segment of optimum segment size reflected with logical features at the time of actual reading/writing from a host computer to a disk. SOLUTION: A CPU 7 sends an instruction to a read/write control part on the basis of respective managing data, for example, and during the idle time of processing, data are read out of a cache memory and written onto a disk. Besides, the CPU 7 has the functions of a disk analytic part 7a for analyzing the logical format of the disk and a cache setting part 7b for setting the segment of the cache memory on the basis of the logical format of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a segment cache type information recording / reproducing apparatus and a segment cache type information recording / reproducing method, and more particularly, to a segment cache type information recording characteristic in a structure setting portion of each segment of a cache memory. The present invention relates to a reproducing apparatus and an information recording / reproducing method of a segment cache system.

[0002]

2. Description of the Related Art Generally, an information recording / reproducing device such as an optical disk device is used as an external recording device of a host computer in an information processing device. In recent years, a cache memory is provided in the middle, and data transfer is performed via the cache memory to speed up data recording and reproduction. ing. In particular, in an optical disk apparatus using an optical disk as a recording medium, since writing to the recording medium takes a lot of time, a disk cache memory for temporarily storing recording data and reproduction data is generally provided.

As a device provided with such a cache memory, for example, in a storage control device disclosed in Japanese Patent Application Laid-Open No. 2-122345, when a data read request is made, the data is sent together with the data requested by the host computer. A so-called read-ahead type cache memory device has been proposed in which data of a further block is pre-read in advance. According to this configuration, in the data requested by the host computer, the data stored in the cache memory is transferred from the cache memory to the host computer without being read from the recording medium, thereby shortening the access time in the read processing. It is possible to further improve the hit rate of the cache memory at the time of reading by the pre-reading process.

Further, in order to improve the access time at the time of write processing, an apparatus having a write-back type cache memory which writes data to a cache memory and then writes the data to a recording medium during an idle time of processing by a CPU has been proposed. Proposed.

In such an information recording / reproducing apparatus, a ring buffer system in which a storage area is used continuously and repeatedly is generally used as a cache memory, so that the data is stored in the cache memory during a write process and a read process. Cannot search for the data that is being saved. Therefore, in some cases, there is a problem that the effect of the cache cannot be sufficiently exhibited.

In view of this, Japanese Patent Application Laid-Open No. 3-176726 proposes a device provided with a segment cache type cache memory which divides a storage area of the cache memory into a plurality of segments for use. By using such a segment cache type cache memory, for example, at the time of read processing, data stored in the cache memory at the time of previous write processing can be searched, and when there is applicable data, the data is read from the cache memory. The processing speed can be improved by transferring the data to the host computer.

In the cache memory of the segment cache system disclosed in Japanese Patent Application Laid-Open No. 3-176726, segment division is determined by tracks of a recording medium.
The number of segments to be divided, the size of each segment, and the like are not considered so much, and there is a problem that sufficient performance cannot be obtained in some cases, such as when random write commands are continuously received.

Japanese Patent Laid-Open Publication No. Hei 10-63578 has a cache memory for temporarily storing data to be read from or written to a disk. The cache memory has a segment cache type cache memory area divided into a plurality of segments. An information recording / reproducing apparatus has been proposed in which a segment cache area is provided to improve the processing speed. The segment cache area is
The number of segments is set so as to be an optimum number of segments determined according to conditions such as the capacity of the main memory of the CPU, and is fixed. The size of each segment is set according to the capacity of the segment cache area. Split,
Sufficient performance is obtained for random write commands.

[0009]

However, in Japanese Patent Laid-Open Publication No. Hei 10-63578, the number of segments is set to a predetermined integer in advance, so that the size of the segment set in the cache memory is simply the size of the cache memory. It is a fixed size divided by the above predetermined integer, and since the structure of the segment does not have logical characteristics when the host computer actually reads and writes to the disk, it is appropriate for the data to be read and written. There is a problem that the size of the segment is not used, the capacity of the cache memory cannot be used effectively, and a sufficient effect of the cache memory cannot be obtained.

The present invention has been made in view of the above circumstances, and has been made in consideration of the above circumstances. When a cache memory of a segment cache system is used, the optimum characteristics which reflect the logical characteristics when a host computer actually reads and writes data on a disk are used. It is an object of the present invention to provide an information recording / reproducing apparatus capable of setting a cache area in a segment having a large segment size, increasing the use efficiency of a cache memory, and improving the processing speed at the time of reading and writing.

[0011]

According to the present invention, there is provided an information recording / reproducing apparatus of a segment cache system in which a storage area is divided into a plurality of segments, and data transferred between an upper host computer and a recording medium in each segment. A cache memory of a segment cache system for temporarily storing data, and cache memory management means for controlling reading and writing of data from and to the cache memory, and managing and searching for data stored in the cache memory. In the information recording / reproducing apparatus of the segment cache system for performing recording / reproducing of data, the cache memory management means comprises: an analyzing means for analyzing a logical format of the recording medium; Setting means for setting the structure Constructed.

In the information recording / reproducing apparatus of the segment cache system according to the present invention, the analyzing means analyzes a logical format of the recording medium, and the setting means sets the structure of each segment of the cache memory based on an analysis result of the analyzing means. When using a segment cache cache memory, the cache area is set to a segment with the optimal segment size that reflects the logical characteristics when the host computer actually reads from and writes to the disk. It is possible to increase the use efficiency of the cache memory and improve the processing speed at the time of reading and writing.

According to the information recording / reproducing method of the segment cache system of the present invention, a storage area is divided into a plurality of segments, and each segment temporarily stores data transferred between a host computer and a recording medium in each segment. In the information recording / reproducing method of reading / writing data from / to the cache memory, managing and retrieving data stored in the cache memory, and recording / reproducing information on / from the recording medium, the logical format of the recording medium is An analysis step for analyzing and a setting step for setting the structure of each segment of the cache memory based on the analysis result of the analysis means are provided.

In the information recording / reproducing method of the segment cache system according to the present invention, the analyzing step analyzes a logical format of the recording medium, and the setting step performs a structure of each segment of the cache memory based on an analysis result of the analyzing step. When using a segment cache cache memory, the cache area is set to a segment with the optimal segment size that reflects the logical characteristics when the host computer actually reads from and writes to the disk. It is possible to increase the use efficiency of the cache memory and improve the processing speed at the time of reading and writing.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 11 relate to a first embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of an information recording / reproducing apparatus, and FIG. 2 is a functional block diagram showing functional blocks of a CPU in FIG. FIG. 3 is a diagram showing a logical format of the disk of FIG. 1, FIG. 4 is a flowchart showing a flow of a main process of the CPU of FIG. 1, FIG. 5 is a flowchart showing a detailed flow of a segment size updating process of FIG. FIG. 6 is a first explanatory view for explaining the operation of the information recording / reproducing apparatus of FIG. 1, and FIG.
FIG. 8 is a second explanatory diagram for explaining the operation of the information recording / reproducing apparatus of FIG. 1, FIG. 8 is a first flowchart showing a detailed flow of a modification of the segment size updating process of FIG. 4, and FIG.
FIG. 10 is a second flowchart showing a detailed flow of a modified example of the segment size updating process. FIG. 10 is an explanatory diagram for explaining the operation of the information recording / reproducing apparatus according to the modified example of the segment size updating process of FIGS. FIG. 11 is a diagram showing a modification of the configuration of the cache memory of FIG.

In the present embodiment, an example of the configuration of a magneto-optical disk drive device that performs recording and reproduction using a magneto-optical disk is shown as an example of an information recording / reproducing device. The present invention can also be applied to an information recording / reproducing device such as a device, a floppy disk device, or an optical card device.

(Construction) As shown in FIG. 1, an information recording / reproducing device 1 which is a magneto-optical disk drive device is connected to a host computer via an interface cable and controls the exchange of commands and data by SCSI (protocol control). A SCSI control unit 2 that performs
A disk control unit 5 connected to the control unit 2 for controlling data exchange with a disk 4 serving as a recording medium rotated by a spindle motor 3, a cache memory 6 for temporarily storing data to be read from and written to the disk 4, A CPU 7 for controlling the operation of each part of the apparatus;
And a main memory 10 serving as a work area for storing data during operation of the CPU 7, and a read / write head 11 for controlling a recording / reproducing head 11 for recording / reproducing data on / from the disk 4. / Write control unit 12.

The capacity of the cache memory 6 is, for example, 1 MB.
= 800H Block (= Sector), a segment cache system in which the entire data area as a cache memory is divided into a plurality of segments, each of which is a plurality of rooms having the same size, and data to be read from and written to the disk 4 is temporarily stored. Is used as a cache memory area (segment cache area) 24 of the.

The main memory 10 stores a drive management data area in which variables (stack area, global variables, etc.) are stored when the operation program of the CPU 7 is executed, and management data (tag table, segment information, etc.) in the segment cache area. And a read / write management data area for storing a read / write parameter queue related to a read / write command.

In the above configuration, a command transferred from a host computer (not shown) is sent to the CPU 7 via the SCSI controller 2. For example, when the command is a write command, the CPU 7 stores the write data in the segment cache area 24 of the cache memory 6 and stores management data related to the write data in the segment cache management data area of the main memory 10. Further, the management data relating to the write command is stored in the read / write management data area of the main memory 10.

When the CPU 7 receives all the data,
The completion of the write command processing is returned to the host computer via the SCSI control unit 2, and an instruction is sent to the disk control unit 5 and the read / write control unit 12 based on the management data. Data is read from the disk 6 and data is written to the disk 4.

As shown in FIG. 2, the CPU 7 analyzes a logical format of the disk 4 by a disk analyzing unit 7a and a cache setting unit 7b that sets a segment of the cache memory 6 based on the logical format of the disk 4.
It has the function of

Here, as shown in FIG. 3, the disk 4 has a physical format of, for example, FAT 16
This is an MB disk, and the size of a cluster (1 logical block: cluster in FAT16) of data handled by the host computer is, for example, 8 sectors. The disk 4 is logically formatted in the FAT mode, and has a Boot Sector, FAT1, FAT2, and RAT.
Each of a D file management area 21 composed of an auto directory and a user area 22 is provided (see FIG. 1).

(Operation) In accordance with the operation program stored in the firmware program storage section 9, the CPU 7 first performs initial setting of each parameter value used for control in step S1, as shown in FIG.
To initialize the apparatus (by rotating the spindle motor 3 so that the recording / reproduction to / from the disk 4 can be performed by the head 11).

Then, in step S3, the segment size of the cache memory 6 is updated.

Thereafter, it is checked in step S4 whether there is any unwritten write cache data in the segment cache 24, and if there is unwritten write cache data, a write process (Write_Cache) to the disk 4 is performed in step S5.

If there is no unwritten write cache data in step S4, it is checked in step S6 whether a command has been received (whether or not the flag cmd = 1). If there is a command to be received and executed, in step S7 After performing the command execution process (CMD_Exe), the command is terminated in step S8, the flag is cleared (cmd = 0), and the process returns to step S4 to repeat the process.

Next, the updating of the segment size of the cache memory 6 in step S3 will be described. As shown in FIG. 5, a Boot Sector is read from the disk 4 in step S11, and the disk analyzer 7a checks the cluster size of the disk 4.

Then, in step S12, the cache setting unit 7b checks the disk 4
Is set as one segment size of the cache memory 6, and the number of segments is calculated by dividing the memory size of the cache memory 6 by the one segment size.

In step S13, the calculated number of segments is compared with a predetermined maximum number Max. If the number of segments is larger than the predetermined maximum number Max, the load of the segment management process increases. Is set to an integer N times (for example, twice) the cluster size of the disk 4, and the memory size of the cache memory 6 is divided by the one segment size to calculate the number of segments, and the process proceeds to step S4 in FIG.

If the number of segments is equal to or smaller than the predetermined maximum number Max in step S13, the number of segments is compared with the predetermined minimum number Min in step S15. If the number of segments is equal to or larger than the predetermined minimum number Min, step S4 in FIG.
If the number of segments is smaller than the predetermined minimum number Min, the size of one segment may be large and the cache memory 6 may not be used efficiently.
By dividing one cluster size by 16 into a size obtained by dividing the cluster size of the disk 4 by an integer N, and dividing the memory size of the cache memory 6 by this one segment size,
After calculating the number of segments, the process proceeds to step S4 in FIG.

That is, in this embodiment, first, the size of the segment of the cache memory is made equal to the size of this cluster. The number of segments is determined by dividing the capacity allocated to the segment cache in the size of the cache memory by the size of the segment.

At this time, if the number of segments becomes too large, which causes inconvenience in the management and use of the segment cache (for example, a shortage of memory for managing the segment cache and an excessively long time for management and search of the segment). ), The number of segments is limited to an arbitrary value. In this case, by adjusting the size of the segment to an integral multiple of the size of the cluster, the number of segments is adjusted to be equal to or less than an arbitrary value.

When the size of the cluster is too large and the number of segments is not sufficient (random W /
R may be slower), or the size of data that is actually read or written is often smaller than the size of the cluster (the use efficiency of the cache (segment) memory is reduced (data starts from the beginning of the cluster). Is used for the size of the data)) sets the segment size to 1 / integer of the cluster size. At this time, the number of segments may be multiplied by an integer or may be increased to an arbitrary value.

Thus, the size or number of segments can be optimized for the logical format of the disk. In addition, by the optimization, the use efficiency of the segment increases, and the speed of reading and writing data can be increased.

The file management area Boot Se
ctor, FAT1, FAT2, Root Direct
Tory is separately managed and used as a segment that matches each size or is 1 / integer size of each size, and the user area is obtained by subtracting the segment capacity required for the file management area from the segment cache capacity. The remaining capacity may be managed and used based on the size and number of segments determined by the method according to the present embodiment. As a result, the size and number of segments can be optimized over the entire disk.

If the size of the data actually read or written is often larger than the size of the cluster (whether the segment management is wasteful or overhead), the size of the segment is made an integral multiple of the size of the cluster. May be set. At this time, the number of segments is reduced.

(Effect) As shown in FIG. 6B, conventionally, for example, when the segment size is determined on the basis of a track, for example, cache memory size = 256 KB = 512 sectors 1 track = 25 logical blocks = 12.5 KB segments Number = 256 KB / 12.5 KB = 201 1 data (file size) = 5 logical blocks = 2.5
If KB, the effective part of the cache memory 6 used at the time of random read / write is 2.5 KB × 20 = 50 KB, and 256 KB−50 KB = 206 KB is a waste area.

In this embodiment, under the same conditions and 1 segment size = 8 logical blocks = 4 KB, the number of segments = 256 KB / 4 KB = 64, 2.5 KB × 64 = 160 KB, and 256 KB−160 KB = 96 KB is wasteful. Area.

By setting one segment size of the cache memory 6 according to the logical format (cluster size) of the disk 4 as in the present embodiment, in the above calculation example, the area of 206 KB-96 KB = 110 KB is used more effectively. can do.

Even when the data size is large, the size of one segment is determined based on the cluster size as in the present embodiment. However, in the conventional method (for example, when one segment size is determined based on the track), there is a possibility that a waste area of a maximum of 24 logical blocks is generated. Therefore, in this embodiment, the cache memory can be used more effectively.

Further, in recent years, the size of one logical block (cluster) of data handled by the host computer changes as the capacity of the disk increases, but in the present embodiment, one segment size is determined based on the cluster size. Therefore, the use efficiency of the cache memory can be improved even for disks having different capacities.

As shown in FIG. 7A, in the disk 4, if the first sector including the file management area and the user area which can be read and written by the host computer is LBA = 0, the host computer An unreadable / writable area or a surplus area smaller than the size of a cluster in which no segment is created occurs. The segment logical block address (segment LBA: first LBA of the segment) is 0 and an integral multiple of the segment size (= the number of sectors per segment).

For this reason, for example, as shown in FIG.
When (segment size) = (cluster size), random writing (clustering is performed for 6 blocks from the beginning of the cluster) of a small capacity file of 6 sectors (cluster = data smaller than 8 sectors) is performed. If so, there is a possibility that 1 file = 2 segments in the cache memory 6, and the cache memory 6 may be used wastefully.

Therefore, as a modification of the first embodiment, the processing shown in FIG.
An example will be described in which a segment size is set by a process of determining how to set a segment LBA according to a BA (LBA of the first cluster). That is, in this modification, the segment LBA is (the head LBA of the user area) ±
(Segment size).

As shown in FIG. 8, the same processing as steps S11 to S16 in FIG. 5 is performed in the modification of the first embodiment. In this modification, in step S11, a Boot Sector is read from the disk 4, the disk analysis unit 7a checks the cluster size of the disk 4, and checks the start LB of the user area 22.
Check A. In step S12, the cache setting unit 7b sets the cluster size of the disk 4 confirmed in step S11 as one segment size of the segment of the cache memory 6, and divides the memory size of the cache memory 6 by the one segment size to obtain the number of segments. Is calculated, and the first LBA of the user area is set as the reference LBA.

In the modification of the first embodiment, when a W / R command is received from the host computer after step S3 in FIG. 4, the request LBA of the W / R command is confirmed as shown in FIG. In step S21, the request LB
A is compared with the reference LBA, and if the required LBA is equal to or greater than the reference LBA, the segment LBA is determined in step S22 as: segment LBA = reference LBA + ｛ (request LBA− reference
LBA) / one segment size ｝ × one segment size, and the process proceeds to step S4 in FIG. 4 (however, the underlined portion of the above expression is truncated to the decimal point).

If the required LBA is smaller than the reference LBA in step S21, the segment LBA is determined in step S23.
Segment LBA = reference LBA- ｛ (reference LBA- request
(LBA) / 1 segment size ｝ × 1 segment size, and the process proceeds to step S4 in FIG. 4 (however, the underlined portion of the above expression is rounded up to the decimal point).

By performing the processing shown in FIG. 9, the processing shown in FIG.
As shown in FIG. 10 (a) showing a disk and FIG. 10 (b) showing a cache memory, for example, random writing of a small capacity file of 6 sectors (cluster = data smaller than 8 sectors) ( When writing is performed for 6 blocks from the beginning of the cluster), 1 file = 1 segment in the cache memory 6, and twice as many files as in FIG. 7 can be stored in the cache, so that writing can be performed at higher speed. it can. In other words, optimization is performed by matching the relationship between the cluster and the segment LBA,
It is possible to increase the use efficiency of the segment and read / write data at high speed.

In this modification, in the segment including LBA = 0, the head of the segment may be an unused area (= cannot be read / written by the host computer).

Further, a C file management area 23 is provided in the cache memory 6 (see FIG. 1), and a Boot Secto is stored in the C file management area 23 of the cache memory 6.
r, FAT1, FAT2, Root Director
y and FAT management is performed, as shown in FIG. 11, Boot Sector is set to Boot Sector.
One segment is secured for the size, and FAT1 / FAT
No. 2 secures one segment for FAT1 / FAT2 size (FAT1 / FAT2 uses the same segment because the same data is written), and Root Direct
The ory may secure one segment for the size of the Root Directory, and the remaining segment cache 24 may secure a segment for the cluster size. By doing so, the FAT management is easy and the disk 4
The relationship between the logical format and the cache memory 6 can be optimized.

FIG. 12 is a flowchart showing a detailed flow of the segment size updating process according to the second embodiment of the present invention.

Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components will be denoted by the same reference numerals and description thereof will be omitted.

This embodiment is an embodiment in which the size of the data of the file read and written by the host computer is monitored, and the size and number of the segments are changed at any time according to the tendency of the data size. is there.

In the present embodiment, steps S4 to S4 in FIG.
It is executed in parallel with S8, checks the size tendency of the write file at the time of W / R, and dynamically changes the structure setting of the segment. That is, as shown in FIG. 12, the size of the data of the file of the read / write command (W / R command) is continuously monitored in step S31.

Then, in step S32, it is determined whether or not the size of the data of the file is less than 1/2 of the cluster size. If the size of the data of the file is less than 1/2 of the cluster size, , Step S3
3 = 1/2 the size of one cluster size
The number of segments is set to twice the size of one cluster size, and the process returns to the point where the interrupt from step S4 to step S6 in FIG. 4 is accepted. If not, the process proceeds to step S34.

In step S34, it is determined whether the size of the file data is biased to about twice or four times the cluster size, and the size of the file data is biased to about twice or four times the cluster size. If there is, the size of the segment is set to 2
4 and the number of segments is set to l / 2 of the size of one cluster, and the process returns to the point where the interrupt from step S4 to step S6 in FIG. 4 is accepted. Otherwise, the process proceeds to step S36.

In step S36, it is determined whether the size of the file data is biased to about one or three times the cluster size, and the size of the file data is biased to about one or three times the cluster size. If so, the size and number of the segments are returned to the values at the time of one cluster size in step S37, and the process returns to the place where the interruption from step S4 to S6 in FIG. 4 is accepted. Otherwise, the data size (file size) is random. Therefore, the size and the number of the segments are kept at the current values, and the values are stored in step S4 in FIG.
Then, the process returns to the point where the interrupt of S6 is accepted.

Thus, it is possible to always set the size and the number of segments that are optimized for the read / write tendency of the host computer.

In this embodiment, the size and number of the segments are set to 1/2 times, 1 times, or 2 times, but may be set to 1/4 times, 4 times, or the like. The condition may be a method other than this embodiment.

Each embodiment of the present invention uses FAT32, N
The same applies to other formats such as TFS and HFS. The confirmation of the logical format of the disk may be performed on the host computer side, and the host computer may instruct the disk cache device to instruct the logical format.

[0063]

As described above, according to the information recording / reproducing apparatus of the segment cache system of the present invention, the analyzing means analyzes the logical format of the recording medium, and the setting means analyzes the logical format of the cache memory based on the analysis result of the analyzing means. Because the structure of each segment is set, when using a cache memory of the segment cache system, the cache area is allocated to a segment of the optimal segment size that reflects the logical characteristics when the host computer actually reads and writes to the disk. This setting has the effect of increasing the use efficiency of the cache memory and improving the processing speed during reading and writing.

As described above, according to the information recording / reproducing method of the segment cache system of the present invention, the analyzing step analyzes the logical format of the recording medium, and the setting step performs each segment of the cache memory based on the analysis result of the analyzing step. When using a cache memory of the segment cache method, the cache area is set to a segment having an optimal segment size that reflects the logical characteristics when the host computer actually reads from and writes to the disk. Thus, the use efficiency of the cache memory can be improved, and the processing speed at the time of reading and writing can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an information recording / reproducing device according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram showing functional blocks of a CPU in FIG. 1;

FIG. 3 is a diagram showing a logical format of the disk shown in FIG. 1;

FIG. 4 is a flowchart showing a flow of a main process of a CPU in FIG. 1;

FIG. 5 is a flowchart showing a detailed flow of a segment size update process in FIG. 4;

FIG. 6 is a first diagram illustrating the operation of the information recording / reproducing apparatus of FIG. 1;
Illustration of

FIG. 7 is a second diagram illustrating the operation of the information recording / reproducing apparatus of FIG. 1;
Illustration of

FIG. 8 is a first flowchart showing a detailed flow of a modification of the segment size updating process of FIG. 4;

FIG. 9 is a second flowchart showing a detailed flow of a modification of the segment size updating process of FIG. 4;

FIG. 10 is an explanatory diagram illustrating the operation of an information recording / reproducing apparatus according to a modification of the segment size updating process of FIGS. 8 and 9;

FIG. 11 is a diagram showing a modification of the configuration of the cache memory of FIG. 1;

FIG. 12 is a flowchart showing a detailed flow of a segment size update process according to the second embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2 ... SCSI control part 3 ... Spindle motor 4 ... Disk 5 ... Disk control part 6 ... Cache memory 7 ... CPU 7a ... Disk analysis part 7b ... Cache setting part 9 ... Firmware program storage part 10 ... Recording / reproduction Head 11: Read / write control unit 21: D file management area 22: User area 24: Segment cache

Claims (8)

[Claims] 1. A segment cache type cache memory for dividing a storage area into a plurality of segments, and temporarily storing data transferred between a host computer and a recording medium in each segment, and data for the cache memory. Read and write control,
A cache memory management unit that manages and searches data stored in the cache memory; and a segment cache type information recording / reproducing apparatus that records / reproduces information on / from the recording medium. An information storage device for analyzing the logical format of the recording medium; and a setting device for setting a structure of each segment of the cache memory based on an analysis result of the analysis device. Playback device. 2. The information recording / reproducing apparatus according to claim 1, wherein the setting unit sets the size of each segment of the cache memory based on an analysis result of the analysis unit. 3. The information recording of the segment cache system according to claim 1, wherein said setting means sets a relationship between each segment of said cache memory and a logical block address based on an analysis result of said analyzing means. Playback device. 4. The setting unit monitors the size of data read / written to / from the recording medium, and determines the size of each segment of the cache memory or the size of the cache memory based on the tendency of the size of the data read / written. 2. The information recording / reproducing apparatus according to claim 1, wherein the size and the number of each segment are set. 5. A read / write control of data to / from a segment cache type cache memory in which a storage area is divided into a plurality of segments and each segment temporarily stores data transferred between a host computer and a recording medium. An information recording / reproducing method for managing and retrieving data stored in a cache memory and recording / reproducing information on / from the recording medium, comprising: an analyzing step of analyzing a logical format of the recording medium; A setting step of setting the structure of each segment of the cache memory based on the result. 6. The information recording / reproducing method according to claim 5, wherein the setting step sets a size of each segment of the cache memory based on an analysis result of the analysis step. 7. The information recording according to claim 5, wherein the setting step sets a relationship between each segment of the cache memory and a logical block address based on an analysis result of the analysis step. Playback method. 8. The setting step monitors a size of data read / written to / from the recording medium, and determines a size of each segment of the cache memory or a size of the cache memory based on a tendency of the size of the data read / written. 6. The information recording / reproducing method according to claim 5, wherein the size and the number of each segment are set.