JPH1078899A - Information recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store large-capacity information at low cost and shorten the total transfer time by selecting a storage device and storing large-capacity data, and also selecting a suitable storage device according to an access state as judgement reference and storing data whose capacity is relatively small. SOLUTION: It is judged (601) whether the capacity of target data is larger than a threshold value and when the capacity is larger, a tape library is set (602) in a local storage device. Then the access frequency A of the target data is compared (604) and (607) with the access frequencies B and C of a semiconductor memory and a magnetic disk, and when the access frequency A is larger than B, the semiconductor memory is set as the local storage device and the magnetic disk is set as another storage device (605). When the access frequency A is larger than C, the magnetic disk is set as the local storage device and the optical library is set as another storage device (608). When the access frequency A exceeds C, the optical library is set as the local storage device (609).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus, and more particularly, to an information recording / reproducing apparatus capable of efficiently recording and reproducing information in a video editing system.

[0002]

2. Description of the Related Art Hierarchical storage systems are conventionally known as large-capacity external storage devices. The hierarchical storage system is a storage in which a plurality of external storage devices having different characteristics, such as a semiconductor memory, a magnetic disk device, an optical disk device, and a magnetic tape device, are hierarchically combined. It can be complemented to.

[0003] As a storage system of the above type, for example, "Epoch-2" of Epoch Systems, USA
FiREX9000 system ". This product hierarchically combines cache memory, magnetic disk drives, magneto-optical disk jukeboxes (MO, WORM) and tape jukeboxes. The file with the oldest access history in multiple file servers and workstation disks connected via a network
By automatically moving to the och-2 storage server, the disk capacity of each server or workstation can be used for activation data. The movement of data between the Epok-2 storage server and the client will be described with reference to FIG.

[0004] A file system usage level called "Water marks" is set for each client. Every day, at the staging interval 901 set by selecting the time of low load, the usage level of the client's file system is set to “LWM (low water mar
k) Automatically stage out until 902 is reached. When the usage ratio of the file system suddenly reaches “HWM (high water mark)” 903, the system automatically stages out some files to reduce the required space. To secure.

[0005] In the Epock-2 storage server, active data is recorded in a cache memory and a magnetic disk drive, inactive data or archive data is recorded in an optical disk jukebox, and backup data is recorded in a tape jukebox or a magneto-optical disk. Also, in order to efficiently store the online catalog of all backup transactions, the latest catalog is stored on a high-speed magnetic disk, and the old catalog is automatically moved to a second storage medium (optical disk). When an old catalog is referred to, it is automatically returned from the optical disk to the magnetic disk.

[0006]

The above-mentioned conventional hierarchical storage system is designed on the assumption that reading or writing of small-capacity data such as code data is repeatedly performed.

However, in a video editing system, a small amount of data of several KB to several MB such as management information is repeatedly read or written, and a large capacity exceeding several GB like video information. Data may be sequentially read or written at high speed in some cases. When the above-described Epok-2 storage server method is applied to such a video editing system, a very large amount of data is moved to the magnetic disk when reading the video information, and the magnetic disk is hardly used thereafter. It is occupied by data that is never accessed. On the other hand, data such as management information that is constantly and repeatedly accessed is staged out on the optical disc. In this case, the data migration time increases, and the hierarchical storage system may not be used efficiently.

An object of the present invention is to provide a high-speed data access even when data to be stored is randomly accessed with a small capacity and data that is sequentially accessed with a large capacity such as moving picture information. To provide an information recording / reproducing apparatus using a hierarchical storage system capable of performing the following.

[0009]

In order to achieve the above-mentioned object, according to the present invention, a storage device group having two or more different types of storage devices, and input / output of information based on a request from an external information device. In the information recording / reproducing apparatus having the controller, the controller determines one of the storage devices (a storage device suitable for large-capacity, sequentially accessed data) in a storage device group for a large amount of data based on a data capacity as a criterion. ) Is selected and stored, and when storing data that is relatively small in data capacity and is randomly accessed, one of the storage devices in the storage device group is selected and stored based on the access state to the data. By doing so, each data is controlled to be stored in a storage device suitable for the characteristics.

The controller includes, for example, a data input / output interface and a SCSI (Small Computer System Int.)
erface), a CPU, and the C
A high-speed memory (for example, a semiconductor memory) for storing a program for determining the operation of the PU and temporary data and management information at the time of control operation, and a storage device group includes, for example,
Various external storage devices having different characteristics such as a semiconductor memory, a magnetic disk, an optical disk, or a magnetic tape (library) are included. Each of these storage devices is connected to the controller by a bus.

Further, the controller writes the data by selecting an optimum external storage device based on the capacity of the data to be stored, the number of accesses in a unit time, and the like. In this case, one piece of data is continuously written in a series of storage areas in the storage device, and management information such as the data capacity, the used external storage device, and its address is stored in the semiconductor memory in the controller. These pieces of management information are copied to the nonvolatile storage device periodically or aperiodically. In addition, in order to avoid that the empty areas in the external storage device are scattered in small pieces, and that new storage information is not divided and stored at remote locations, the stored data in the external storage device is periodically or aperiodically stored. To make efficient use of storage capacity.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of an information recording / reproducing apparatus according to the present invention.

The information recording / reproducing apparatus includes a data input / output interface 101, a CPU 102, a semiconductor memory 103,
Controller 10 including bus interface 104 and the like
5, a plurality of external storage devices having different characteristics such as a semiconductor memory 106, a magnetic disk 107, an optical library 108, and a tape library 109; these external storage devices (106, 107, 108, 109) and the controller 105; And a bus 110 for connecting the.

The semiconductor memory 103 inside the controller 105 stores the external storage devices (106, 107, 1).
08, 109), an index information storage area 111 for storing management information related to data in the storage area, a work area 112 for temporarily storing data during a control operation,
And a program area 113 executed by the CPU 102. If the semiconductor memory 103 has a sufficient storage capacity, a part of the storage area of the semiconductor memory 103 is used instead of the semiconductor memory 106 as an external storage device. Conversely, when the storage capacity of the semiconductor memory 103 is insufficient, a part of the semiconductor memory 106 provided as an external storage device is used instead of the semiconductor memory 103 inside the controller.

Data (or command) 114 sent from the upper part of the controller is input / output interface 101
(115). The CPU 102 determines a data transfer method based on the program and various information (111, 112, 113) stored in the controller 105, and sends the data or command to the bus interface 104 (116). These data or commands are sent from the bus interface 104 to an external storage device (for example, the semiconductor memory 106) designated by the CPU 102 via the bus 110.

When a read command is given to the semiconductor memory 106, data read from the semiconductor memory is transferred in the order of 117, 116, 115 and 114.
When a write command is given to the semiconductor memory 106, if the continuous free space of the semiconductor memory is smaller than the capacity of the write data, the number of accesses per unit time of the data stored in the semiconductor memory is reduced. Small data is transferred to the magnetic disk 107 (118), thereby forming a continuous free area in the semiconductor memory 106, and thereafter, write data is transferred from the bus interface 104 to the semiconductor memory 106 (11).
7). These controls are performed by the CPU 102.

The CPU 102 executes the following every time data is accessed.
The index information area 111 is rewritten. Also, in preparation for occurrence of an abnormality such as a power failure, the contents of the index information area 111 in the semiconductor memory 103 are stored in a non-volatile storage device (such as the magnetic disk 107, the optical library 108, or the tape library 109) periodically or non-periodically. Is saved. Also, the file data is moved in the external storage device so that the new storage information is not divided and stored at a remote location, so that the free space is scattered in pieces in various storage devices. An instruction for continuation is issued periodically or aperiodically. Information necessary for making these determinations is stored in the index information area 111. Details of the processing performed by the CPU 102 will be described later with reference to FIGS.

FIG. 4 shows the structure of the index information area 111. Each time a data access request is generated, the index information area 111 includes management information necessary for determining an optimal storage device for the data. Further, in the index information area 111, for all data,
The title of the data, the data capacity, the type of the storage device in which the data is stored, the start address of the data block, and the time of access to the data generated within a unit time are stored. The access time within the unit time records the access time generated within the unit time registered in advance, and the number of accesses within the unit time is calculated by counting the access time. In addition to the items described above, information specific to the video editing system, for example, the last change time, the last changer's name, and the like may be stored in the index information area. The information in the index information area 111 may be stored in a text format, or may be stored in a bit on / off state defined in advance for each item.

FIGS. 2, 3 and 10 are diagrams for comparing the characteristics (characteristics) of various external storage devices used for the hierarchical storage. Numerical values in parentheses in FIG.
4 shows values calculated based on the numerical values in FIG.

FIG. 2 shows the relationship between storage capacity (total capacity) and cost for each storage device (semiconductor memory, magnetic disk, optical library, tape library). For example, it can be seen that the tape library has the highest cost among the above four types of storage devices when the total capacity is several GB, but has the lowest cost when the total capacity is 1,000 GB or more. For each storage device, there is a range of total capacity that is more economical than other storage devices, and in order from those for small capacity, the order of semiconductor memory, magnetic disk, optical library, tape library is Become.

FIG. 3 shows the relationship between the data capacity of each storage device and the total transfer time.

Here, the total transfer time represents the time from the reception of a command to the end of data transmission, that is, the sum of the access time and the data transfer time. When the data capacity is several hundred MB or less, the tape library is the device having the longest total transfer time among the above four types of storage devices.
When the data capacity becomes several hundred MB or more, it becomes the second high-speed storage device following the semiconductor memory.

2 and 3, the semiconductor memory is a device having a very short total transfer speed irrespective of the data capacity. However, as the total capacity becomes large, the cost becomes high. Therefore, it can be said that the storage device is suitable for storing frequently accessed data. Compared with the above-mentioned semiconductor memory, the magnetic disk has a longer total transfer time in the entire data capacity range, but has a lower cost in the whole data capacity range. Is suitable for storing data having a relatively large number of accesses. For the same reason, the optical library is suitable for storing data having a larger data capacity than a magnetic disk and a relatively small number of accesses per unit time.

2 and 3, the tape library has a total transfer time shorter than that of the optical library when the data capacity exceeds several hundred MB, but the cost is lower than that of the optical library when the total capacity is 1000 GB or more. ing. Therefore, when storing a large number of large data having a data capacity not less than a certain threshold,
Tape libraries are suitable for both cost and total transfer time. The threshold in this case is represented by the following equation.

Threshold [B] = {A_tape−A_opt) / (V_tape−V
_opt)} * (V_opt) * (V_tape) where A_tape: tape library access time [s] V_tape: tape library transfer speed [B / s] A_opt: optical library access time [s] V_opt: optical library access time Transfer speed [B / s] Note that the above threshold is the total transfer time of the tape library and optical library (data capacity is C [B], access time is A
[S], and if the transfer rate is V [B / s], it can be expressed as C / V + A).

Using the numerical example shown in FIG. 10, the threshold value is about 271 MB. Therefore, a tape library is suitable for storing data having a capacity of 271 MB or more, regardless of the number of accesses within a unit time.

FIG. 5 is a flowchart showing a control procedure of the controller.

When an access request is issued to certain data (step 501), the access time is changed (5).
02). This means that if there is a description of the time of access outside the unit time, it is deleted, and the current access time is added. It is determined whether the access request is for reading (50).
3) In the case of a read request, read is performed (50).
4) In the case of a write request, the data storage location is determined without doing anything. At this time, as will be described in detail with reference to FIG. 6, the storage location is changed if necessary (505: "Process 1").

FIG. 6 shows the details of "processing 1".

It is determined whether or not the capacity of the data (target data) for which the access request has occurred is larger than the above-described threshold (601). If it is larger, a tape library is set in its own storage device (602), and FIG. "Process 3" described in detail later is performed (603). Here, the “own storage device” is a storage device selected by the controller to store target data. On the other hand, as will be described later, if there is no free space for storing the target data in the self-storage device, it is necessary to move a part of the data stored in the self-storage device to another storage device to make free space in the self-storage device. Occurs. This other storage device is called “other storage device”.

On the other hand, if the capacity of the target data is not larger than the threshold, the number of accesses A per unit time of the target data is compared with the minimum value B of the number of accesses per unit time of the semiconductor memory (604). If the access count A is larger than B, the self-storage device = semiconductor memory and the other storage device = magnetic disk are set (605), and “Process 2” described in detail in FIG. 7 is performed (606). If the number of accesses A is not larger than B, the number of accesses A of the target data per unit time is compared with the minimum value C of the number of accesses of the magnetic disk per unit time (607). After setting the self-storage device = magnetic disk and the other storage device = optical library (608), "Process 2" is performed (606). If the number of accesses A is not larger than C, the self-storage device = optical library is set (609), and then "process 3" is performed (603).

FIG. 7 shows the details of "processing 2".

It is determined whether or not the target data exists in the self-storage device (701). If the target data exists, the process is terminated. If the target data does not exist in the self-storage device, it is determined whether or not a free area corresponding to the capacity Mo of the target data exists in the self-storage device (7).
02) If it exists, the target data is stored in a free area of its own storage device (703), and then this processing is terminated. In the determination step 702, if a free area corresponding to the capacity of the target data exists as a discontinuous partial area in the self-storage device, the storage data in the self-storage device is moved, and Step 703 may be performed after an area is created.

In step 702, if there is no free area corresponding to the capacity Mo of the target data in the own storage device, the current free capacity Mv is stored in the own storage device.
And the capacity Md of data having the number of accesses smaller than the number of accesses of the target data per unit time, and the sum M
Is greater than the capacity Mo of the target data (704). When the capacity M is larger than Mo, the data stored in the self-storage device is evacuated to the work area 112 in ascending order of the number of accesses per unit time so that the free capacity Mv is larger than the capacity Mo of the target data ( 708) After the target data is stored in the obtained free area of the storage device (709), this processing ends. Here, in order to create a continuous free area in the local storage device,
In step 708, the data may be moved within the self-storage device together with the above-described data saving. The saved data is stored in another storage device.

On the other hand, if the capacity M is smaller than Mo in step 704, the target data cannot be stored in its own storage device, so that the target data is stored in another storage device. First, it is determined whether the other storage device is an optical library (705). If the other storage device is an optical library, the optical library is set as it is as its own storage device (707), and the process 3 is performed (603). In step 705, if the other storage device is not an optical library, that is, if the other storage device is a magnetic disk, the own storage device is replaced with a magnetic disk.
The other storage device is set to the optical disk (706), and the process 2 is performed again (606).

FIG. 8 shows the details of the "process 3".

It is determined whether or not the target data exists in the self-storage device (801). If the target data exists, the process is terminated. If the target data does not exist, it is determined whether or not there is a free area corresponding to the capacity of the target data in the self-storage device (802). If there is a free area, the target data is stored ( After 804), this process ends. If the free area exists as a discontinuous partial area, the data may be moved in the own storage device to form a continuous free area, and then the target data may be stored.
If there is no free space corresponding to the capacity of the target data, an error display indicating that the capacity is exceeded is output, the processing is interrupted (803), and the operation according to the operation of the operator thereafter is performed.

In the above embodiment, an example of a control operation in which data is moved within a storage device or between storage devices upon a data access request (read or write) has been described. The movement of data between the storage devices may be performed periodically independently of the data access request. The same applies to the operation of writing information in the semiconductor memory 103 to the nonvolatile storage device.

[0040]

According to the present invention, a large amount of information can be stored at low cost by automatically selecting a storage device in accordance with the capacity and access frequency of target data.
The total transfer time can also be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an information recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a cost and a total capacity of a storage device.

FIG. 3 is a diagram illustrating a relationship between a total transfer time of a storage device and a data capacity.

FIG. 4 is a diagram showing a structure of an index information area in the present invention.

FIG. 5 is a flowchart illustrating an example of a control procedure of a controller according to the present invention.

FIG. 6 is a flowchart showing details of processing 1 in FIG. 5;

FIG. 7 is a flowchart showing details of a process 2 in FIG. 6;

FIG. 8 is a flowchart showing details of a process 3 in FIG. 6;

FIG. 9 is a diagram illustrating an example of data movement of a conventional hierarchical storage.

FIG. 10 is a comparison diagram showing characteristics of various external storage devices.

[Explanation of symbols]

101: data input / output interface, 102: CP
U, 103: semiconductor memory, 104: bus interface, 105: controller, 106: semiconductor memory, 1
07: magnetic disk, 108: optical library, 109:
Tape library, 111: index information, 11
2: work area, 113: program, 901: staging interval, 902: LWM, 903: HWM.

Claims (4)

[Claims] An information recording / reproducing apparatus comprising: a storage device group including two or more different types of storage devices; and a controller for inputting and outputting information to and from the storage device group based on a request from an external device. If there is a data storage request from an external device, the controller selects a predetermined storage device from the storage device group using the data capacity as a criterion, and the data capacity does not reach the criterion. When storing data, one of the storage devices in the group of storage devices is selected based on the access state of the data as a criterion. If the capacity of the selected storage device is insufficient, the one of the storage devices is selected. An information recording / reproducing apparatus, wherein the data is stored in the one storage device by saving a part of the data already delivered to the storage device. 2. The information recording / reproducing apparatus according to claim 1, wherein the storage devices in the storage device group include a semiconductor memory, a magnetic disk, an optical disk library, and a tape library. 3. The optical library according to claim 2, wherein the access time of the optical library is A_opt, the transfer speed of the optical library is V_opt,
When the access time of the tape library is A_tape and the transfer speed of the tape library is V_tape, the amount of data accessed is {(A_tape -A_opt) / (V_tape-V_opt)}
An information recording / reproducing apparatus characterized in that when the value is larger than a threshold value represented by the formula of V_opt * V_tape, the information is stored in a tape library. 4. The data storage system according to claim 3, wherein data already stored in the tape library is continuously stored in the tape library irrespective of the number of accesses within a predetermined period of time in the past. Information recording characterized in that data already stored in the optical disk library is moved so that the data is stored in the semiconductor memory, the magnetic disk, and the optical disk library in ascending order of the number of accesses within a fixed time in the past. Playback device.