JP2008257584A - Ram disk processing method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the compression rate of a RAM disk image while maintaining the compatibility of a RAM disk with the data format of an existing file system. <P>SOLUTION: In the RAM disk processing method for reading the RAM disk image compressed and stored in a secondary storage device in starting use of the RAM disk, storing it in a memory, and compressing and storing the RAM disk image to the secondary storage device in terminating the use of the RAM disk, an invalid area of the RAM disk is cleared prior to the compression storage processing of the RAM disk image. The clear processing is performed by continuously writing predetermined data 0' to the invalid area, for example, just before storing the RAM disk image to the secondary storage device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a RAM disk processing method and system, and more particularly to an operation process of a RAM disk that compresses a RAM disk image and stores it in a secondary storage device in an information processing apparatus such as an embedded device that has limited computer resources.

  Generally, in an information processing system, a recording medium such as a hard disk (HDD) or a compact flash (registered trademark) is used for storing data. However, these recording media have the following disadvantages: (1) the access speed is slow, (2) the medium itself may be damaged if a system failure occurs during access. As a technique for compensating for this drawback, a RAM disk using a random access memory (RAM) as a recording medium has been put into practical use.

  The RAM disk does not break the RAM, which is a recording medium, even if a system failure occurs, but has the disadvantage that data is lost each time the system is stopped. Therefore, when a RAM disk is used, an operation is performed in which the contents of the RAM disk are stored in another recording medium such as an HDD when the system is stopped, and the RAM disk is restored from the recording medium when the system is activated.

  For example, Japanese Patent Laid-Open No. 2003-122647 discloses a technique for saving the contents of a RAM disk in a secondary storage device when a failure is detected in the information processing apparatus. In particular, a device is devised to reduce the recording amount of the secondary storage device by compressing the RAM disk image and storing only the effective area of the RAM disk during the storage.

JP 2003-122647 A

  In a general file system, since only management information is deleted when a file is deleted, previously recorded data is left in an invalid area in the disk image. Therefore, if the method of compressing the RAM disk image described in Patent Document 1 is continuously used, the compression rate gradually decreases in order to compress the RAM disk image including the data remaining in the invalid area. There is. When the compression rate decreases, the data compression process (data modeling and encoding process) becomes complicated, and a secondary problem that the compression processing time increases occurs.

  Japanese Patent Application Laid-Open No. 2005-228561 describes another method for storing only the effective area of the RAM disk. Although this method does not cause the above problems, the created RAM disk image is stored in a format different from the file system image of the original RAM disk, so there is a problem that compatibility with other systems is lost. is there.

  In system maintenance of an embedded device that uses a RAM disk, the RAM disk image is read from the embedded device, the RAM disk image is mounted on another management terminal, the contents are updated, and then the updated RAM disk image is assembled. Operation to write back to the embedded device is being performed. If the RAM disk image is not compatible with other systems, the RAM disk image cannot be mounted on the management terminal, which hinders operation.

  In addition, when an emergency stop of the information processing device becomes necessary due to a power failure or battery shortage, it is necessary to quickly save the RAM disk to the secondary storage device, but in order to save only the effective area of the RAM disk The management area of the RAM disk needs to be checked, and an embedded device with low processor performance has a problem that processing takes time.

  An object of the present invention is to provide a RAM disk processing method and system capable of improving the compression rate of a RAM disk image while maintaining compatibility of the RAM disk with the data format of an existing file system.

The processing of the RAM disk according to the present invention (first invention) is preferably performed by reading out the RAM disk image compressed and stored in the secondary storage device when storing the RAM disk and storing it in the memory. Realized by clearing the invalid area of the RAM disk before compressing and saving the RAM disk image in the RAM disk processing method that compresses and saves the RAM disk image to the secondary storage device when the use of the RAM disk is terminated. Is done.
Preferably, the clear process is performed by continuously writing predetermined data, for example, zero 0 ', in the invalid area immediately before saving the RAM disk image to the secondary storage device.
Preferably, the clearing process is performed by dividing the invalid area by an arbitrary capacity and continuously writing predetermined data while using the RAM disk.
Preferably, the clear process is performed by continuously writing predetermined data to an invalid area of the RAM disk when deleting a file or reducing a file size.

The RAM disk processing method (second invention) according to the present invention is preferably a first device (for example, an information processing device) that uses a RAM disk and a second device (for example, a management terminal) that manages a RAM disk image. ) Are connected via a network, the first device reads the RAM disk image from the second device when it starts using the RAM disk, stores it in the memory, and stores the RAM disk image when it ends the use of the RAM disk. In a method of processing a RAM disk that is read from a memory and stored in a second device,
When the RAM disk usage rate is less than the first reference value, the first device performs a process of clearing the invalid area of the RAM disk and a process of compressing the RAM disk image,
When the RAM disk usage rate is less than the second reference value, the second device performs a process of clearing the invalid area of the RAM disk and a process of compressing the RAM disk image,
When the RAM disk usage rate is equal to or greater than the second reference value, the RAM disk processing method for storing the RAM disk image in the second device without compressing the RAM disk image without performing the process of clearing the invalid area of the RAM disk. Composed.

In the RAM disk processing method according to the present invention (third invention), preferably, a first device that uses a RAM disk and a second device that manages a RAM disk image are connected via a network. The first device reads the RAM disk image from the second device when starting to use the RAM disk and stores it in the memory, and reads the RAM disk image from the memory when finishing using the RAM disk and transfers it to the second device. In the processing method of the RAM disk to be stored, the second device performs maintenance processing by updating the RAM disk image distributed to the first device in the second device, and after the maintenance processing is completed, the second device After clearing the invalid area of the RAM disk generated by the maintenance process, Configured as a processing method for RAM disk to store over di compression processing to.
The present invention can also be understood as an information processing system and program for executing the first to third processes.

According to the present invention, when a RAM disk image is stored in a secondary storage device, the RAM disk image compression ratio is improved while maintaining the compatibility with the existing system by clearing the invalid area of the RAM disk. It is possible.
Also, by executing the clear process of the invalid area separately for each capacity while using the RAM disk, the clear process can be omitted when saving the RAM disk image, and the RAM disk image save process is accelerated. can do.
In addition, the RAM disk compression ratio is improved by clearing the invalid area of the RAM disk when deleting the file and reducing the file size, and by setting all the invalid areas to be cleared when saving the RAM disk image. Can do.

Further, according to the second invention, the invalid area clear process and the RAM disk image compression process are performed in the first apparatus or the second apparatus according to the utilization rate of the RAM disk, or the RAM disk By storing the RAM disk image without compressing it without clearing the invalid area, the RAM disk can be operated in consideration of the balance between the network load and the compression processing time.
According to the third invention, the second device performs maintenance by updating the RAM disk image to be distributed to the first device in the second device, and after the maintenance process is completed, the second device By compressing and saving the RAM disk image after clearing the invalid area of the RAM disk generated in the maintenance process, the compression rate of the RAM disk can be improved.

[Example 1]
Hereinafter, an embodiment will be described with reference to the drawings.
FIG. 1 shows a configuration of an information processing system in one embodiment. The configuration of the information processing apparatus 1 shown in the figure shows various functions realized by executing the program. The configuration of the hardware of the information processing apparatus 1 is shown in FIG. First, referring to FIG. 15, an information processing apparatus 1 includes a CPU 1501 that executes a related program to realize a predetermined processing function, and a memory 1502 that stores a program to be executed and a RAM disk image related to the present invention. , A secondary storage device 1503 such as an HDD for storing a RAM disk image and various programs, a device adapter 1504 for connecting devices, and a communication interface unit 1505 for connecting to an external network. The hardware configuration of the information processing apparatus 1 is the same in the first to fourth embodiments described later.

  Next, referring to FIG. 1, a user application (UAP) 3 is executed by the CPU 1501 to control the device 13 and process data acquired therefrom. For example, the UAP 3 drives the device 13 in accordance with an instruction from a higher-level device (not shown) connected to the external network 11, and returns the processing result to the higher-level device. The device 13 is various devices driven via the serial driver 12, and specifically, is an RFID reader / writer, a temperature sensor, an infrared sensor, or the like. The information processing apparatus 1 can communicate with the external network 11 via the network driver 10.

The RAM disk image 8 is stored in the secondary storage device 2, and the CPU 1501 reads the RAM disk image 8 stored in the secondary storage device 2 at the time of startup into the memory 1502 via the disk driver 9, and the RAM disk image 7 is configured. The RAM disk image 8 includes various files used by the OS (Operating System), the USP 3 and the file system 5.
The storage processing unit 4 mounts the RAM disk image 8 from the secondary storage device 2 to the memory 1502 when the information processing device 1 is started, and unmounts the RAM disk 7 when the information processing device 1 is stopped. A process of saving the RAM disk image in the secondary storage device 2 via the driver 9 is performed. In this embodiment, a characteristic process is performed when the RAM disk is unmounted.

Normally, when the CPU 1501 performs data processing, the UAP 3 accesses the RAM disk 7 via the file system 5. The file system 5 interprets the data stored in the RAM disk 7 so that the UAP 3 can use the RAM disk 7 as a tree-structured file system. Further, the file system 5 stores the frequently used data in the cache 6 when accessing the RAM disk 7, thereby reducing the number of accesses to the RAM disk 7.
Since the information processing apparatus 1 controls the device 13, it may be called a device control terminal, and its name is not specified.

FIG. 2 shows the memory configuration of the RAM disk 7 and the cache 6.
The RAM disk 7 includes a file system management area 71, a file management area 72, and a data block area 73. The file system management area 71 is an area for storing management information of the file system itself such as the disk size, the number of free data blocks, and the volume name. The file management area 72 is an area for recording attribute information of each file such as a file size, a file update date and time, and a file access right. The data block area 73 is an area for storing the contents of each file.

The memory structure of the cache 6 is the same as that of the RAM disk 7 and comprises a file system management area 61, a file management area 62, and a data block area 63. Since only the data related to the actually accessed file is stored in the cache 6, the size of the file management area 62 and the data block area 63 is smaller than the area of the corresponding RAM disk 7. Since the file system management area 61 copies the file system management area 71 of the RAM disk 7 as it is, the area sizes are equal.
Here, since an invalid area is generated in the file management area 72 and the data block area 73 when a file is deleted or updated, a clear process as described later is performed. However, since all the system management information held in the file system management area 71 is basically valid, the clear process is not performed on this area.

FIG. 3 shows a memory configuration of the file management area 72 in the RAM disk 7.
The file management area 72 has a structure in which a plurality of file management information 75 follows the bitmap 74. The file management information 75 has a one-to-one correspondence with the file and includes attribute information 76 and a block list 77. The attribute information 76 records attribute information of each file such as file size, file update date and time, and file access right. The block list 77 holds the address of the data block 79 in which the file contents are recorded. When the file size increases, one file normally uses a plurality of data blocks 79, so the block list 77 is configured to record the positions of the plurality of data blocks.

  The bitmap 74 is a bitmap indicating whether each entry of the file management information 75 in the file management area 72 is valid or invalid. That is, if the Nth bit of the bitmap 74 is 1 (valid), the Nth entry in the file management information 75 is valid. For example, if the file is deleted, the file management information 75 corresponding to the deleted file becomes invalid, so that the file system 5 changes the corresponding bit of the bitmap 74 from 1 (valid) to 0 (invalid).

FIG. 4 shows a memory configuration of the data block area 73 in the RAM disk 7.
The data block area 73 has a configuration in which a bit map 78 is followed by a plurality of data blocks 79. The contents of the file are recorded in the data block 79 and referred to from the block list 77 in the file management information 75.
The bitmap 78 is a bitmap indicating whether each entry of the data block 79 is valid or invalid. That is, if the Nth bit of the bitmap 78 is 1 (valid), the Nth entry in the data block area 73 is valid. For example, if the file is deleted or the file size is reduced, the data block used by the file becomes invalid, so that the file system 5 changes the corresponding bit of the bitmap 78 from 1 (valid) to 0 (invalid). Changed to

  Hereinafter, a procedure in which the storage processing unit 4 stores the RAM disk image of the RAM disk 7 in the secondary storage device 2 when the information processing apparatus 1 is stopped will be described. When the file system 5 reduces the file size or deletes the file, it simply sets the bit of the bitmap 74 in the file management area 72 and the bit of the bitmap 78 in the data block area 73 to 0 (invalid). 75 and data block 79 are not cleared. Therefore, the previously used data remains in the invalid area (the invalid file management information 75 and the data block 79) of the RAM disk 7, and if the RAM disk 7 is compressed as it is, it remains in the invalid area. Since the data is also compressed, the compression rate decreases. Therefore, the storage processing unit 4 checks the contents of the RAM disk when the system is stopped, and performs zero clear processing on the invalid area. Since the compression rate of data cleared to 0 is very good, this improves the compression rate of the entire RAM disk 7 and shortens the compression processing time.

Next, the operation of the storage processing unit 4 when the information processing system is stopped will be described with reference to the flow of FIG.
When the stop processing of the information processing apparatus 1 is started, the storage processing unit 4 requests the file system 5 to unmount the RAM disk 7. The file system 5 writes back the data stored in the cache 6 that needs to be written back to the RAM disk 7, and then unmounts the RAM disk (S10).
In the following processing operation, the storage processing unit 4 accesses the RAM disk 7. At this time, the storage processing unit 4 directly accesses the RAM disk 7 without going through the file system 5. For example, in the case of a UNix system, the RAM disk 7 is directly accessed by accessing a device file corresponding to the RAM disk.

  The storage processing unit 4 sequentially checks the bits recorded in the bitmap 74 in the file management area 72 of the RAM disk 7 (S11). If the bit is 0, the corresponding file management information 75 is invalid, so the entry of the file management information 75 is cleared. That is, if the Nth bit of the bitmap 74 is 0 (invalid), 0 ′ is written in the memory area used by the entry of the Nth file management information 75. If the bit is 1, the corresponding file management information 75 is valid, so the 0 clear process is not performed (S12, S13). The storage processing unit 4 repeats the processing of S11 to S13 until the processing of the last bit of the bitmap 74 is completed (S14).

Subsequently, the storage processing unit 4 sequentially checks the bits recorded in the bitmap 78 in the data block area 73 of the RAM disk 7 (S15). If the bit is 0, the corresponding data block 79 is invalid. As a result, the entry of the data block 79 is cleared to 0. That is, if the Nth bit of the bitmap 78 is 0 (invalid), 0 ′ is written into the memory area used by the Nth data block 79. If the bit is 1, the corresponding data block 79 is valid, so the 0 clear process is not performed (S16, S17). The storage processing unit 4 repeats the processing of S15 to S17 until the processing of the last bit of the bitmap 78 is completed. (S18)
With the above processing, all invalid areas in the RAM disk 7 are cleared to zero. Finally, the storage processing unit 4 compresses the data on the RAM disk 7 and stores it as the RAM disk image 8 in the secondary storage device 2 (S19). Thus, the storage processing of the RAM disk 7 by the storage processing unit 4 is completed.

In this embodiment, the clear process is performed by writing 0 'as predetermined data in the invalid area. However, the predetermined data is not limited to 0' as long as it is a simple pattern. For example, -1 ' May be written. The same applies to the following embodiments.
In the above example, the zero clear process is performed on the invalid areas of both the file management area 72 and the data block area 73, but only one of them may be performed to reduce the processing time. Moreover, you may implement partially, without performing all the 0 clear processes with respect to each invalid area | region.
In the above example, the process is performed when the system is stopped normally. However, the process may be performed when an emergency stop of the system is necessary due to a shortage of the remaining battery level or a system failure.

In the above example, by defragmenting the RAM disk 7 between steps S10 and S11, the compression rate of the RAM disk 7 in S19 is further improved. The defragmentation process is a process for eliminating the fragmentation in the RAM disk 7. By this, invalid areas of the disk area are connected, so that the compression rate of the RAM disk 7 is improved. However, since the defragmentation process generally takes time, it is preferably performed only when the processor performance of the CPU 1501 of the information processing apparatus 1 is good or it may take some time to stop the system. Here, an existing tool can be used for the defragmentation process.
In this embodiment, when an existing file system corresponding to the cache function is used, a cache may be created even for a RAM disk. However, a RAM disk using a RAM as a recording medium may not require a cache. Good.

[Example 2]
In the first embodiment, since the invalid area 0 clear process of the RAM disk is performed when the system is stopped, the system stop process may take time. In the second embodiment, the invalid area of the RAM disk is divided and the zero clear process is performed during system operation, so that the invalid area 0 clear process of the RAM disk when the system is stopped becomes unnecessary or reduced. As a result, the speed of the system stop process can be increased.

FIG. 6 shows the configuration of the information processing apparatus 1 in this embodiment.
The difference from the first embodiment is that a disk checker 14 is added. Since the operation of the information processing apparatus 1 in the present embodiment is substantially the same as that in the first embodiment, differences will be described below.
The disk checker 14 is periodically started during the system operation of the information processing apparatus 1, and clears the invalid area of the RAM disk by several blocks while referring to the cache 6. Therefore, when the system is stopped, most or all invalid areas of the RAM disk 7 are already cleared to zero. When the system is stopped, the storage processing unit 4 unmounts the RAM disk 7 and immediately compresses the RAM disk 7 and stores it in the secondary storage device 2. That is, S19 is performed after S10 in FIG. 5, and the processing of S11 to S18 is omitted.

FIG. 7 shows the memory structure of the cache 6.
Since the cache 6 is partially copied from the RAM disk 7, it is substantially the same as the memory configuration of the RAM disk 7 shown in FIGS. The file management area 62, the bitmap 64, and the file management information 65 of the cache 6 correspond to the file management area 72, the bitmap 74, and the file management information 75 of the RAM disk 7. Similarly, the data block area 63, the bitmap 68, and the data block 69 of the cache 6 correspond to the data block area 73, the bitmap 78, and the data block 79 of the RAM disk 7.

  However, a management number 65a and a management number 69b are added to the file management information 65 and the data block 69 in order to indicate which part of the RAM disk is a copy. The management number 65 a added to the file management information 65 indicates what number of the file management information 75 recorded in the file management area 72 in the RAM disk 7 corresponds to the file management information 65. The management number 69 b added to the data block 69 indicates the number of the data block 79 that is recorded in the data block area 73 in the RAM disk 7.

  In addition, in order to indicate whether or not each file management information 65 and data block 69 needs to be written back to the RAM disk 7, a Dirty bit 65b and a Dirty bit 69c are added to the file management information 65 and the data block 69. Yes. If it is necessary to write back, 1 is set in the dirty bit 65b and the dirty bit 69c, and 0 is set if it is not necessary to write back. If the file management information 65 or the data block 69 becomes invalid due to file deletion or file size reduction, the file system 5 discards the memory occupied by these entries without writing them back even if these entries are Dirty. To do.

  As for the bitmap 64 and the bitmap 68, all information is copied from the RAM disk 7 to the cache 6, and is a complete copy of the bitmap 74 and the bitmap 78 in the RAM disk. Therefore, the validity / invalidity of the file management information 65 and the data block 69 can be determined by referring to the bitmap 64 and the bitmap 68 in the cache 6. Since the file system 5 writes these back to the RAM disk 7 whenever the bitmap 64 and the bitmap 68 are changed, the Dirty flag is not added to the bitmap 64 and the bitmap 68. Of course, in order to make the write-back process more efficient, a Dirty flag may be added to them.

  The disk checker 14 is periodically activated, and refers to the bitmap 64 and the bitmap 68 to clear 0 the invalid file management information 75 and the data block 79 in the RAM disk 7. Since the invalidated area is not written back from the cache 6 to the RAM disk 7, the disk checker 14 does not clear the file management information 65 and the data block 69 in the cache 6 to zero.

With reference to FIG. 8, the zero clear processing operation of the invalid area of the RAM disk will be described.
This process is a process periodically performed by the disk checker 14. The disk checker 14 holds two variables therein: a file management area index number and a data block area index number. The file management area index number is a bit number to be checked in the bitmap 64 of the file management area 62. The data block area index number is a bit number to be checked in the bitmap 68 of the data block area 63.

When the disk checker 14 is activated, it requests the file system 5 to lock the access to the RAM disk 7 and the cache 6 (S20). As a result, access from the UAP 3 to the RAM disk 7 is temporarily blocked.
Next, the disk checker 14 checks the bit of the file management area index number for the bitmap 64 in the file management area 62 of the cache 6 (S21). If the bit is 0 (invalid), the corresponding file management information 75 in the file area 72 of the RAM disk 7 is cleared to 0 (S22, S23). The disk checker 14 increments the file management area index number, and repeats the processes of S21 to S23 until it checks a certain number. When the file management area index number exceeds the final bit number of the bitmap 64, it is reset to 0 (S24, S25).

  Next, the disk checker 14 checks the bit of the data block area index number for the bitmap 68 in the data block area 63 of the cache 6 (S26). If the bit is 0 (invalid), the corresponding data block 79 in the data block area 73 of the RAM disk 7 is cleared to 0 (S27, S28). The disk checker 14 increments the data block area index number, and repeats the processing of S26 to S28 until it checks a certain number. When the data block area index number exceeds the final bit number of the bitmap 68, it is reset to 0 (S29, S30).

Next, the disk checker requests the file system 5 to unlock the access to the RAM disk 7 and the cache 6. Thereby, access to the RAM disk 7 from the UAP 3 is resumed. Thus, the RAM disk invalid area 0 clear process by the disk checker 14 is completed.
In the above example, the processing of the disk checker 14 is periodically executed. However, the disk checker 14 may cooperate with the OS scheduler to execute the above-described processing when the system is in an idle state. Good.

[Example 3]
In the second embodiment, since the invalid area 0 clear process of the RAM disk is periodically performed, the zero clear process of all invalid areas may not be completed when the system is stopped. In this embodiment, the file system 5 clears the invalid area to 0 when an invalid area is generated in the RAM disk 7 due to file deletion or file size reduction. This ensures that all invalid areas of the RAM disk are cleared to 0 when the system is stopped, and the compression rate of the RAM disk is improved.

The configuration of the information processing apparatus 1 in the present embodiment is the same as that in the first embodiment. That is, when the system is stopped, the storage processing unit 4 unmounts the RAM disk 7 and immediately compresses the RAM disk 7 and stores it in the secondary storage device 2.
The operation of the file system 5 in this embodiment is different from those in the first and second embodiments. Hereinafter, the processing operation of the file system 5 will be described focusing on the differences. When the file system 5 deletes a file stored in the RAM disk 5 or reduces the file size, the invalid area generated in the RAM disk is cleared to zero.

With reference to FIG. 9, the zero clear processing operation of the invalid area of the RAM disk by the file system 5 will be described.
When the UAP 3 instructs the file system 5 to delete the file or reduce the file size, the file system 5 checks the block list 77 in the file management information 75 corresponding to the file, and the data recorded in the block list 77. Necessary ones of the blocks are deleted from the block list 77. That is, in the case of file deletion, the addresses of all data blocks described in the block list 77 are deleted. When the file size is reduced, the address of the data block corresponding to the reduced portion is deleted. Then, the file system 5 sets the bit corresponding to the deleted data block to 0 (invalid) for the bitmap 78 in the data block area 73. The bit number of the bit to be 0 'is
([Address of deleted data block] − [start address of data block]) / [size of data block 79] Note that the processing in this step is the same as the operation of a general file system (S40).

Next, the file system creates a list of data blocks deleted in S40 (S41), and clears all the data blocks 79 described in the list to zero. The processing in this step is a processing operation characteristic of the present embodiment (S42, S43).
In the case of file size reduction, the file system 5 completes the processing. In the case of file deletion, since it is necessary to invalidate the file management information 75 corresponding to the file to be deleted, the process proceeds to the next step (S44).

The file system 5 sets the bit indicating the file management information 75 corresponding to the file to be deleted to 0 (invalid) for the bitmap 74 in the file management area 72. The bit number of the above bit is calculated from ([address of file management information 75]-[start address of file management information]) / [size of file management information 75]. Note that the processing in this step is the same as the operation of a general file system (S45).
The file system 5 clears 0 the file management information 75 corresponding to the file to be deleted. The processing in this step is a processing operation characteristic of the present embodiment (S46). This completes the file deletion or file size reduction process.

In the above example, the file system 5 performs processing on the RAM disk 7, but if a part of the file management area 72 or data block area 73 to be processed exists in the cache 6, It is necessary to perform processing on both of the RAM disks 7. In this case, the process of setting the bit of the bitmap to 0 (invalid) (S40, S45) is performed on the bitmaps of both the cache 6 and the RAM disk 7, but the invalid area 0 clearing process (S41 to S43, S46). ) Is performed only for the data block 79 and the file management information 75 in the RAM disk 7. The data block 69 and the file management information 65 in the cache 6 are discarded by the file system 5 when these entries become invalid, and need not be cleared to zero.
[Example 4]
The built-in device as the device 13 has a small capacity of the built-in secondary storage device and may not be able to store a RAM disk image. Therefore, in this embodiment, the information processing apparatus itself does not hold the RAM disk image in the secondary storage device, and a plurality of information processing apparatuses download and use the RAM disk image from the management server when the RAM disk use starts. When the use is finished, the RAM disk image is uploaded to the management server.

  By compressing the RAM disk image, the network load associated with uploading / downloading the RAM disk image can be reduced. However, when the invalid area in the RAM disk decreases, the effect of compressing the data of the RAM disk image decreases, and the increase in the compression processing time becomes remarkable particularly in an embedded device having low performance. Therefore, in this embodiment, the apparatus for compressing the RAM disk image is switched in accordance with the usage rate of the RAM disk. If the usage rate of the RAM disk is equal to or higher than the reference value, the RAM disk image is stored without being compressed. As a result, the operation considering the balance between the network load and the compression processing time becomes possible.

FIG. 10 shows the configuration of the information processing system in this embodiment.
This system is configured by connecting a plurality of information processing apparatuses 101 to 10 n (all may be collectively referred to as information processing apparatus 1) to the management server 16 via the network 11. The management server 16 stores the RAM disk images 801 to 80n (may be collectively referred to as the RAM disk image 80) of the plurality of information processing apparatuses 101 to 10n existing in the system in the secondary storage device 20. The management DB 22 holds a correspondence relationship between each RAM disk image 80 and the identifier of the information processing apparatus 1, and the management program 17 manages the RAM disk image 80 in cooperation with the management DB 22. The storage processing unit 4 of the information processing apparatus 1 downloads the RAM disk image from the management server 16 via the external network 11 when the information processing apparatus 1 is started up, and uploads the RAM disk image to the management server 16 when the information processing apparatus is stopped. To do. The identifier of the information processing apparatus 1 may be anything as long as it can identify the information processing apparatus 1. For example, the MAC address of the network interface assigned to the information processing apparatus 1 may be used. In FIG. 10, illustration of devices connected to the information processing apparatus is omitted.

Next, a processing operation for downloading a RAM disk image from the management server 16 to the information processing apparatus 1 will be described with reference to FIG.
For example, when the information processing apparatus 101 is activated, the storage processing unit 4 transmits a request message including the identifier of the information processing apparatus 1 to the management server 16 to request a RAM disk image held by the management server 16. Upon receiving this request message, the management program 17 searches the management DB 22 for a RAM disk image corresponding to the identifier included in the request message, and transmits the RAM disk image 801 to the information processing apparatus 101 (S50).

  The management program 17 determines whether or not the RAM disk image T3 is compressed at the start of transmission of the RAM disk image T3, and transmits compression information indicating whether or not the RAM disk image T3 is compressed to the management terminal 1. Subsequently, the management program 17 transmits the RAM disk image T3 to the management terminal 1. The storage processing unit 4 receives the compression information, and determines whether or not the received RAM disk image is compressed (S51).

  The storage processing unit 4 performs processing for downloading a RAM disk image and creation of the RAM disk 7 in a pipeline manner. That is, if the RAM disk image is not compressed, the storage processing unit 4 repeatedly downloads the RAM disk image and copies it to the RAM disk 7 several bytes at a time (S52). On the other hand, if the RAM disk image is compressed, the storage processing unit 4 repeatedly downloads the RAM disk image, decompresses the compressed data, and copies the data to the RAM disk 7 by several bytes (S53). Of course, when there is sufficient free memory in the information processing apparatus 1 or when the information processing apparatus 1 includes the secondary storage device 1503 having a sufficient capacity, the entire RAM disk image is temporarily stored in the memory or the secondary storage device 1503. After downloading, the RAM disk 7 may be created.

  When the download of the RAM disk image is completed, the storage processing unit 4 mounts the RAM disk 7 (S54). In this example, the compression information and the RAM disk image are transmitted. In addition to the above data, the hash value of the RAM disk image calculated in the management server 16 is transmitted from the management server 16 to the information processing apparatus 1. The apparatus 1 may be configured to separately calculate a hash value of the received disk image, compare these two hash values, and redo the download process if they do not match. As a result, data alteration due to communication failure or the like can be prevented.

Next, a process of uploading a RAM disk image from the information processing apparatus 1 to the management server 16 will be described with reference to FIG.
When the information processing apparatus 1 starts the stop process, the storage processing unit 4 unmounts the RAM disk 7 and obtains the usage rate of the RAM disk 7. The storage processing unit 4 checks the bitmap 74 in the file management area 72 and regards the number of bits that are 0 as “the number of invalid file management information 75”. Further, the bitmap 78 in the data block area S73 is checked, and the number of bits that are 0 is regarded as “the number of invalid data blocks 79”. And the capacity of the invalid area,
[Number of invalid file management information 75] × [size of file management information 75] + [number of invalid data blocks 79] × [size of data blocks 79].
The utilization rate of the RAM disk 7 can be calculated by 1− [capacity of invalid area] / [total capacity of RAM disk].
In this example, the number of invalid file management information 75 and the number of invalid data blocks 79 are calculated by checking the bitmap 74 and the bitmap 78. These pieces of information may be held and used (S60).

  When the usage rate of the RAM disk 7 is calculated, processing for switching the compression processing of the RAM disk image is performed next in accordance with the usage rate of the RAM disk 7. That is, the obtained utilization rate of the RAM disk 7 is compared with a predetermined reference value (for example, 50%) (S60). As a result, if the utilization rate is smaller than the reference value, the storage processing unit 4 will be described in S11 to S18. In this procedure, the invalid area is cleared to 0 (S62), and the RAM disk image that has been cleared to 0 is compressed and transmitted to the management server 16. At this time, the storage processing unit 4 transmits the compression information indicating that the RAM disk image is compressed and the identifier of the information processing apparatus 1, and then transmits the compressed RAM disk image. Preferably, the RAM disk image compression and transmission processing are performed in a pipeline manner. That is, compression processing and transmission processing of the RAM disk image are performed every several bytes. As a result, even when the information processing device 1 has little free memory, a RAM disk image having a large capacity can be transmitted to the management server 16 (S63).

  On the other hand, if the usage rate of the RAM disk 7 is equal to or greater than the reference value (50%) (S60), the storage processing unit 4 manages the compression information indicating that the RAM disk image is not compressed and the identifier of the information processing apparatus 1. After the transmission to the server 16, the RAM disk image is transmitted as it is without being compressed (step 64). In the processes of S63 and S64, the hash value of the RAM disk image calculated in the information processing apparatus 1 is transmitted to the management server 16 in the same manner as the process described in the RAM disk image download process. The hash values calculated separately in the management server 16 may be compared, and processing may be performed so that uploading is performed again if they do not match.

Next, a processing operation in which the management server 16 receives a RAM disk image from the information processing apparatus 1 will be described with reference to FIG.
When the system shown in FIG. 10 is cited, the management program 17 of the management server 16 indicates that the RAM disk utilization rate is lower than the reference value (for example, 80%) when the RAM disk image received from the information processing apparatus 1 is not compressed. If it is smaller, the RAM disk image is compressed and stored in the secondary storage device 1503. Preferably, when the management server 16 sets the reference value for compression to be larger than the reference value for the information processing apparatus 1 to perform compression, the compression processing is performed within the information processing apparatus 1 when the compression rate is high and the compression processing time is short. On the contrary, when the compression rate is low and the compression processing time is long, the compression processing is performed in the management server 16. As a result, the operation considering the balance between the network load and the compression processing time becomes possible.

  The management program 17 of the management server 16 receives the compressed information and the identifier of the information processing apparatus 1 from the information processing apparatus 1. The management program 17 determines whether the RAM disk image is compressed from the compression information. Further, the management program 17 accesses the management DB 22 and obtains the RAM disk image 8 to be stored from the identifier of the information processing apparatus 1. Subsequently, the management program 17 receives the RAM disk image (S70).

If the RAM disk image is compressed, the received RAM disk image is stored in the RAM disk image 80i obtained in S70, and the process is terminated (S71, S76). If the RAM disk image is not compressed, the management program 17 obtains the usage rate of the RAM disk image in the same procedure as S60 (S72). If the usage rate is smaller than a reference value (for example, 80%), the invalid area of the RAM disk is cleared to 0 by the same procedure as S62 (S74), the RAM disk data is compressed, and the RAM disk image obtained in S70 The process is saved at T3 (S75, S76).
On the other hand, if the usage rate is equal to or greater than the reference value (80%), the RAM disk image is not compressed and stored in the RAM disk image T3 obtained in S70, and the process is terminated (S73, S76).

Next, the maintenance process operation of the RAM disk image will be described with reference to FIG.
In the system of FIG. 10, for example, system maintenance is performed by batch updating the RAM disk images 801 to 80n in the management server 16. At the time of maintenance, the management program 17 sequentially mounts the RAM disk image T3 that needs to be updated on its own file system, and updates the file in the RAM disk image T3. In this process, a file is created / deleted / updated in the RAM disk image T3, so that an invalid area is newly generated in the RAM disk. Therefore, after the update process is completed, the management program 17 checks the RAM disk images 801 to 80n, clears the invalid area to 0, compresses it, and saves it in the secondary storage device. This suppresses a decrease in the compression rate of the RAM disk image.

  Referring to FIG. 14, when system maintenance is started, the management program 17 selects a RAM disk image 80i that needs to be updated in accordance with an instruction from the administrator (S80). The above instructions may be performed one by one from the console screen of the management server 16 by the administrator, or may be automatically performed according to a script created in advance.

  If the RAM disk image 80i selected in S80 is compressed, the management program 17 expands the RAM disk image 80i (S81, S82), and mounts the expanded RAM disk image 80i on its own file system ( S83). If the RAM disk image 80i is not compressed, the management program 17 mounts the RAM disk image 80i as it is on its own file system (S81, S83).

  Next, the management program 17 accesses the file system in the RAM disk image 80i and performs maintenance on the RAM disk image 80i. In this processing step, application installation / uninstallation / update, consistency check of setting files and registry information, presence / absence of a program not intended by the user, such as a computer virus, is performed (S84).

Next, the management program 17 unmounts the RAM disk image 80i (S85), and obtains the usage rate of the RAM disk image in the same procedure as S60 (S86). If the utilization rate is smaller than the reference value (80%), the RAM disk image selected in S80 is cleared after the invalid area of the RAM disk is cleared to 0 by the same procedure as S62 (S88) and the RAM disk image is compressed. The data is stored in 80i and the process is terminated (S89, S90).
On the other hand, if the usage rate is equal to or higher than the reference value (80%), the RAM disk image is not compressed and stored in the RAM disk image 80i obtained in S80, and the process is terminated (S87, S90).

1 is a configuration diagram of an information processing system in Embodiment 1. FIG. 1 is a diagram illustrating a configuration of a RAM disk and a cache according to Embodiment 1. FIG. FIG. 3 is a diagram illustrating a configuration of a file management area 72 in a RAM disk according to the first embodiment. 3 is a diagram showing a configuration of a data block area 73 in a RAM disk according to Embodiment 1. FIG. FIG. 3 is a flowchart showing a RAM disk compression / storage processing operation according to the first embodiment. FIG. 6 is a configuration diagram of an information processing system according to a second embodiment. The figure which shows the structure of the file management area | region in a cache, and a data block. FIG. 10 is a flowchart showing a zero clear processing operation of an invalid area of a RAM disk in the second embodiment. FIG. 10 is a flowchart showing a zero clear processing operation of an invalid area of a RAM disk in the third embodiment. FIG. 10 is a configuration diagram of an information processing system according to a fourth embodiment. FIG. 10 is a flowchart showing a RAM disk image download processing operation according to the fourth embodiment. FIG. 10 is a flowchart showing an operation of uploading a RAM disk image according to the fourth embodiment. FIG. 15 is a flowchart showing a RAM disk image reception processing operation in the management server 16 according to the fourth embodiment. FIG. 15 is a flowchart showing a RAM disk image maintenance processing operation in the management server 16 according to the fourth embodiment. 1 is a hardware configuration diagram of an information processing apparatus 1 in Embodiment 1. FIG.

Explanation of symbols

1: Information processing device 2, 20, 1503: Secondary storage device 3: User application (UAP) 4: Storage processing unit 5: File system 6: Cache 7: RAM disk 8, 801 to 80n: RAM disk image 13: Device 14: Disc checker
16: Management server 20: Secondary storage device 22: Management DB 17: Management program

Claims (12)

When the use of the RAM disk is started, the RAM disk image compressed and stored in the secondary storage device is read from the RAM disk and stored in the memory, and when the use of the RAM disk is finished, the RAM disk image is stored in the secondary storage. A method of processing a RAM disk for compressing and storing in a device, wherein the invalid area of the RAM disk is cleared before the RAM disk image is compressed and stored. 2. The RAM disk processing method according to claim 1, wherein the clear process is performed by continuously writing predetermined data in the invalid area immediately before the RAM disk image is stored in the secondary storage device. . 2. The method of processing a RAM disk according to claim 1, wherein the clearing process is performed by dividing the invalid area by an arbitrary capacity and continuously writing predetermined data while using the RAM disk. 2. The RAM according to claim 1, wherein the clearing process is performed by continuously writing predetermined data into an invalid area of the RAM disk when deleting a file or reducing a file size. Disc processing method. A first device that uses the RAM disk and a second device that manages the RAM disk image are connected via a network, and the first device uses the RAM disk image as the second device when it starts using the RAM disk. In a RAM disk processing method of reading from a device and storing it in a memory, and reading out the RAM disk image from the memory and storing it in the second device when the use of the RAM disk is terminated,
When the usage rate of the RAM disk is less than the first reference value, the first device performs a process of clearing the invalid area of the RAM disk and a process of compressing the RAM disk image,
When the usage rate of the RAM disk is less than a second reference value, the second device performs a process of clearing the invalid area of the RAM disk and a process of compressing the RAM disk image,
When the usage rate of the RAM disk is equal to or greater than the second reference value, the RAM disk image is stored in the second device without being compressed without performing the process of clearing the invalid area of the RAM disk. A method for processing a RAM disk, which is characterized. A first device that uses the RAM disk and a second device that manages the RAM disk image are connected via a network, and the first device uses the RAM disk image as the second device when it starts using the RAM disk. In a RAM disk processing method of reading from a device and storing it in a memory, and reading out the RAM disk image from the memory and storing it in the second device when the use of the RAM disk is terminated,
The second device performs maintenance processing by updating the RAM disk image distributed to the first device in the second device,
After the maintenance process is completed, the second device clears the invalid area of the RAM disk generated by the maintenance process, and then compresses and stores the RAM disk image. Processing method. In an information processing system that loads and uses a RAM disk image from a secondary storage device that stores a RAM disk image including at least a file,
A storage processing unit that includes a memory that stores the loaded RAM disk image and a CPU that executes a program, and that stores at least the RAM disk image in the secondary storage device by executing the program by the CPU And a file system for managing files contained in the RAM disk stored in the memory,
When the use of the RAM disk ends, the storage processing unit clears the invalid area of the RAM disk, compresses the cleared RAM disk image, and stores it in the secondary storage device An information processing system characterized by this. 8. The information processing system according to claim 7, wherein the storage processing unit continuously writes predetermined data in the invalid area before storing the RAM disk image in the secondary storage device. A disk checker unit that executes in cooperation with the file system, and the disk checker unit divides the invalid area into arbitrary capacity and writes predetermined data continuously while using the RAM disk. The information processing system according to claim 7. 8. The file system according to claim 7, wherein the file system continuously writes predetermined data in an invalid area of the RAM disk when deleting a file or reducing a file size. Information processing system. The RAM disk has a file system management area for storing management information of the file system, a file management area for recording attribute information of each file, and a data block area for storing the contents of each file,
11. The storage processing unit performs an invalid area clear process in at least one of the file management area and the data block area in the RAM disk loaded in the memory. One of the information processing systems. A program executed in an information processing apparatus that loads and uses a RAM disk image from a secondary storage device that stores a RAM disk image including at least a file, and unloads the RAM disk image into the secondary storage device A RAM disk storage processing program that clears an invalid area of the RAM disk and compresses the cleared RAM disk image.

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