JPS6234227A - Auxiliary memory device - Google Patents

Abstract

PURPOSE:To attain the transfer of data with no seeking time required by providing a memory to store the information equivalent at least to several pieces of information stored in a disk type storage device. CONSTITUTION:A CPU 10 receives a data transfer request from a host CPU 2 and checks whether or not the corresponding data is included in an index table 14. If the table 14 contains the data, this data is stored in a data recording memory 12. Thus, the CPU 10 refers to the table 14 and reads the desired data out of the memory 12 to send it to the CPU 2. In this case, no seeking time is needed at all. If said data is not included in the table 14, the CPU 10 reads the desired data out of a magnetic disk device 8 to send it to the CPU 2 and also to store it in the memory 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an auxiliary memory device comprising a disk-type storage device and a disk controller that controls writing and reading from a host copier to the storage device.

[Prior Art] In recent years, disk-type auxiliary storage devices have become larger in capacity as storage density has increased. Along with this, the shape of the disk has become smaller. The miniaturization of this disk is
The drive device can be made smaller, and has advantages such as lower power consumption and lighter weight.

Incidentally, in order to downsize the drive device, it is necessary to downsize the magnetic head moving device as well. Therefore, stepping motors have conventionally been used as drive motors.

However, the performance of this motor is the travel time of the magnetic head (
There is a drawback that it takes time (hereinafter referred to as seek time). Since this seek time is caused by physical operations, it is difficult to shorten it.

Therefore, M! It is conceivable to provide a buffer memory for one sector in the disk controller that controls the data.

According to this, if the information to be accessed next is stored in the backup memory, data can be transferred to the post computer at high speed.

[Problems to be Solved by the Invention] However, this conventional approach is effective when reading data in a fixed order, but when accessing data randomly, it is necessary to buffer the next data in advance. Since it cannot be stored in memory, in that case the disk must be accessed directly. Therefore, there is a drawback that seek time is required and data transfer is slow.

The present invention has been made to solve the two drawbacks.
To provide an auxiliary memory device that can transfer frequently accessed information without directly accessing the disk, and thus without requiring seek time, even when data is accessed randomly. shall be.

[Means for Solving the Problems] The present invention provides an auxiliary memory device consisting of a disk-type storage device and a disk controller that controls writing, reading, and reading from a host copying device to the storage device. As a means for solving the problem, as shown in FIG. 1, there is provided a storage means capable of randomly accessing at least several pieces of information stored in the storage device, and information stored in the storage means. An index means for retaining the index of the index so that it can be referenced.

When there is a request to transfer information from the host computer, the 7th stage of the index is referred to, and if the information is stored in the storage means, the information is transferred from the 1st stage of the storage, and the information is stored. When the information to be written is sent from the host computer, the relevant information is read out from the storage device and transferred, and the information to be written is sent from the host computer by referring to the first stage of the index. When information is stored in the seventh storage stage, writing the information to the disk-type storage device and the storage means,
When the information is not stored.

A control means for controlling writing of the information in the storage device is characterized.

[Operation] In the above configuration, the storage means stores at least several pieces of information stored in the storage device in a randomly accessible manner. This memory can be rewritten by a control means described later. That is, when there is an access from the host computer, the information is accessed from this tl! f is stored in one stage. Furthermore, even if the information is stored for -.times., if it is not accessed thereafter, it is replaced by information that is accessed more frequently.

The 7th index stage holds the index of the information stored in the memory 1 stage so that it can be referenced.

For example, each piece of information is stored in a table format using the start address and the like as an index. This index is rewritten as the contents stored in the storage means are changed.

When information is accessed from the host computer, the control means first refers to the index to check whether the information is stored in the storage means. Refer to the first row of the index above.

When the information is stored in the storage means, if it is a request to transfer information, the information is transferred from the storage means;
When writing information, it acts to write the information into the disk-type storage device and the seven storage stages. Further, by referring to the indexing means, if the information is not stored, if it is a request to transfer information, the information is read from the storage device, transferred, and stored in the storage means; When writing information, control is performed to write the information into the storage device.

Due to this operation, the present invention stores information accessed by the host computer in a randomly accessible manner, so there is no need for seek time required when reading information from a disk, and the waiting time of the host computer is reduced. It can be eliminated. Furthermore, since not all information stored on the disk is stored, there is no need to set the capacity of the storage means excessively, which is economical.

- On the other hand, it is necessary to refer to the index every time there is an access, but since frequently accessed information is preferentially stored in the storage means, it is possible to reduce the seek time as a whole, which is much longer than the time required to refer to the index. can. Therefore, it is possible to speed up data transfer.

[Example] Embodiments of the present invention will be described with reference to the drawings.

<Configuration of Example> FIG. 2 shows an embodiment of the auxiliary memory device of the present invention.

In the embodiment shown in the figure, a node 6 connected to a host computer 2 via an input/output interface 4 includes a magnetic disk device 8, a central processing unit (hereinafter abbreviated as CPU) 10, and a data recording system. memory 12, index table 14, and direct memory access circuit (hereinafter referred to as D).
It is abbreviated as MA. ) IB.

The magnetic disk device 8 includes a main body 8a and a head control section 8b.
Data is exchanged between the host computers 2 and 2 under the control of the cPU to.

The data recording memory 12 constitutes a storage means that is a component of the present invention, and is made of, for example, a random access memory, has a storage capacity equivalent to at least several sectors of the magnetic disk device 8, and has a storage capacity of at least several sectors of the magnetic disk device 8. memory 12
is CPU10 by referring to the index table 14.
The configuration is such that the most recently read data is preferentially stored in the host computer 2 under the control of the host computer 2. That is,
When the first new data is read from the magnetic disk device 8 to the host computer 2 in a state where information is stored for the storage capacity, this new data is the oldest accessed data among the currently stored data. It is structured so that it is remembered in place of day and evening.

The index table 14 constitutes an index-L stage, which is a component of the present invention, and is composed of, for example, a random access memory, and includes a data recording memory 1 therein.
The storage start address in the magnetic disk device 8 and the storage start address in the data recording memory 12 of the data stored in the data storage device 2 are stored in a table format.

Further, the index table 14 is configured to place parameter information regarding the most recently accessed data at the top under the control of the CPU 1O. Therefore, when new data is sequentially read out, parameter information regarding the data that has been read up to that point is sequentially placed at the lower level. And data recording memory 1
When the storage capacity of the index table 2 becomes full, the lower data is discarded, and the newly accessed data is placed on the index table 14 and stored in the data recording memory 12.

The CPUIG constitutes a control means that is a component of the present invention. This CPU10 accepts each data read/write request command from the host computer 2, interprets it, and stores the corresponding data in magnetic disk drive according to the parameters sent at the same time. 18 or reading from the data recording memory 12, or magnetic disk device a
8 or controls when writing data into the data recording memory 12.

DMA1B is a circuit that directly transfers data between the magnetic disk device 8 and the data recording memory 12 without the intervention of the CPU10.

<Operation of the Embodiment> In the above configuration, a case will be described in which the host computer 2 requests the auxiliary memory device to transfer data.

In this case, first, a read command and parameters specifying data are sent from the host computer 2 to the auxiliary memory device via the input/output interface 4. As this parameter, for example, the storage address of the data in the magnetic disk device 8 is used. CPU10 is
These read commands and parameters are received from bus 6 and decoded. It also refers to the index table 14 to see if the storage address of the data exists.

Here, if the storage address of the data exists in the index table 14, the data is stored in the data recording memory 12. Therefore, CPU10
refers to the index table 14, reads the target data from the data recording memory 12, and sends it to the host computer 2 via the bus 6 and input/output interface 4.
send to In this case, no seek time is required.

On the other hand, the storage address of the data is the index.

If the CPU10 does not exist in the stable 14,
Reads the target data from the magnetic disk device 8 and transfers it to the bus 6.
and sent to the host computer 2 via the input/output interface 4. In this case, seek time is required. However, this type of state occurs only in the case of data that is accessed relatively infrequently, so in the case of data that is frequently accessed and rarely occurs, such a -sS state occurs only at the beginning, and may not occur later. rarely occurs.

By the way, the same data is stored in the data recording memory 12 at the same time or after the data is sent to the host computer 2. For this storage, the storage start address of the data in the magnetic disk drive 8 and the storage start address of the data recording memory 12 are set in the index table 14. As the storage start address in the data recording memory 12, the address of the lowest data to be discarded after this data is written is used.

Note that the data recording memory 12 is transferred from the magnetic disk device 8.
When transferring data to, the CPU 1O is not involved, and data can be transferred using DMA tilt. In this case, CPU10 causes DMA1B to hold the storage address of the data.

Next, a case will be described in which data is written from the host computer 2 to the auxiliary memory device.

In this case, first, a write command and a parameter specifying an address at which data is to be stored are sent from the host computer 2 to the auxiliary memory device via the input/output interface 4. CPU10 receives these write commands and parameters from bus 6 and decodes them. Then, DMAI& is caused to hold the storage address of the data. It also refers to the index table 14 to see if the storage address of the data exists.

Here, if the storage address of the data exists in the index table 14, the data is stored in the data recording memory 12. Therefore, CPU10
First, data from the host computer 2 is stored in the corresponding address of the magnetic disk device 8. At the same time, the index table 14 is referred to and target data is written to the corresponding address of the data recording memory 12.

Here, data may be written in the data recording memory 12 and then transferred from the data recording memory 12 to the corresponding address of the magnetic disk device @8.
In this case, when CPU10 interprets the command, the DMA
If the storage address of the data is held in the IEI, the data can be directly transferred later without the intervention of the CPU 10. In this case, no seek time is required.

On the other hand, if the storage address of the data does not exist in the index table 14, the CPU 10 stores the data from the host computer 2 at the corresponding address of the magnetic disk device 8. In this case, seek time is required. But like this! Since B if is a case of data that is accessed relatively infrequently, it occurs only rarely.

[Effects of the Invention] The present invention has the following features: 1. Even when data is randomly accessed, frequently accessed information can be transferred without directly accessing the disk, and therefore without requiring seek time. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an auxiliary memory device of the present invention, and FIG. 2 is a block diagram showing the configuration of an embodiment of the auxiliary memory device of the present invention. 2... Host computer 4... Input/output interface 6... Bus 8... Magnetic disk device 10... Central processing unit (CPU) 12... Data recording memory 14... Index table 16 ...Direct Memory Access Circuit (DMA) Applicant Computer Service Co., Ltd. Agent Patent Attorney Iwao Mishina Figure 1

Claims (1)

[Scope of Claims] An auxiliary memory device comprising a disk-type storage device and a disk controller that controls writing and reading from a host computer to the storage device, wherein at least several items of information stored in the storage device are provided. storage means that can store information in a randomly accessible manner; index means that retains an index of the information stored in the storage means so that it can be referenced; When the information is stored in the storage means, the information is transferred from the storage means, and when the information is not stored, the information is read from the storage device and transferred. When information to be stored and written in the storage means is sent from the host computer, the index means is referred to and if the information is stored in the storage means, the disk-type storage device and An auxiliary memory device comprising: control means for writing the information in the storage means and for controlling the writing of the information in the storage device when the information is not stored.