JPH0431131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a virtual disk control method for an expanded storage device.

[Conventional technology]

2. Description of the Related Art Conventionally, information processing apparatuses have been known that are provided with an extended storage device that is capable of extremely high-speed data transfer between the main storage device and the main storage device. In such conventional information processing devices, the expanded storage device is used only as a temporary file, so the data held by the user is transferred at a much faster transfer speed than the expanded storage device. For example, it had to be used on a magnetic disk device because of its slow speed.

In view of these circumstances, a control method for an extended storage device that can also be used as a permanent file has been proposed (for example, in Japanese Patent Application No.
(See No. 178722). This is to make the data format on the expanded storage device similar to that of a magnetic disk device, and to simulate the expanded storage device as if it were a magnetic disk device when an input/output request is made.

FIG. 7 is an explanatory diagram of the control method according to the above proposal. When using the main storage device 6 and the expansion storage device 5 capable of high-speed data transfer as a virtual disk device, the user program 1, its object program 2, and the RTP (runtime input/output routine) included in the object program 2 A runtime package) 3 and an operating system (OS) 4 are involved. When used as a virtual disk device, it is necessary to temporarily transfer data stored in a magnetic disk device (not shown) to the extended storage device 5 via the main storage device 6.
This processing is performed by a normal utility program. Further, the processed results are outputted or stored again in a magnetic disk device, for example. In order to enable access as a high-speed virtual disk device without changing the user program 1, and to enable smooth processing of data evacuation, etc., the data format on the extended storage device 5 is set to the same format as a magnetic disk. It is said that User program 1
When the RTP 3 identifies that the request is for a virtual disk device in response to an input/output request to the virtual disk device, it passes control to the OS 4. OS
4 simulates the extended storage device as if it were a magnetic disk device, passes data to the program in response to input requests, and outputs the count part and key part as necessary in response to output requests. It is added to the beginning of the target data and stored on the extended storage device 5 via the main storage device 6.

[Problem that the invention seeks to solve]

By the way, when simulating the operation of a magnetic disk device, for example in search processing, it is necessary to refer to many records on the extended storage device. On the other hand, although extended storage devices can transfer data with the main storage device, they generally cannot be directly accessed by a processor. Therefore, according to the method of referencing records by transferring data from the expanded storage device to the main storage device on a record-by-record basis, data transfer between the expanded storage device and the main storage device is frequently required. , there is a problem that processing efficiency decreases.

The present invention solves these problems,
The purpose is to reduce the frequency of input/output between the extended storage device and the main storage device when simulating the operation of a magnetic disk device.

[Means for solving problems]

In order to achieve the above object, the present invention provides a virtual disk control method for an expanded storage device in an information processing apparatus having a main storage device and an expanded storage device capable of data transfer between the main storage device and the expanded storage device. When controlling the virtual disk of the expanded storage device by adjusting the data format on the storage device to the data format of the magnetic disk device and making it possible to access the expanded storage device as a virtual disk device, a virtual disk is created on the main storage device. A plurality of track image buffers are provided to hold the latest image for one track in a disk device, and when simulating the operation of a magnetic disk device when accessing a virtual disk device, data reference operations necessary for access are performed on the track image buffers. Input/output between the track image buffer and the extended storage device is performed on a track-by-track basis, and reading of track contents from the extended storage device to the track image buffer is necessary for any track image buffer. This is performed when the content of the track to be stored is not held, and the writing of the track content from the track image buffer to the extended storage device is performed when the content held in the track image buffer is changed to another track content. and when the simulation of the channel program for the virtual disk device has been completed, and even though the contents of the track held up to that point have been updated, they are not reflected in the expanded storage device. do.

[Effect]

Multiple track image buffers on the main storage device hold the latest images of multiple tracks of a virtual disk device, and when simulating the operation of a magnetic disk device, data necessary for access is referenced on this track image buffer. Operations such as search operations, read operations, and write operations are performed, and data transfer between the extended storage device and the main storage device is performed in units of tracks. Therefore, the input/output frequency between the expanded storage device and the main storage device is reduced by transferring in units of tracks compared to the case of transferring in units of records. Also, the track contents are read from the extended storage device to the track image buffer when the required track contents are not held in any of the track image buffers. The track contents are written when the contents held in the track image buffer are changed to different track contents, and when the simulation of the channel program for the virtual disk device is completed and the contents of the tracks held until then are changed. Since this is performed when the update has not been reflected in the extended storage device, the number of inputs and outputs between the extended storage device and the track image buffer is reduced, and simulation is performed more efficiently.

〔Example〕

FIG. 1 is a main part block diagram showing an example of an information processing device to which the present invention is applied, in which 10 is a main storage device, 11 is an expanded storage device used as a virtual disk device, and 12 is a main storage device 10 and expanded storage device. a transfer means for inputting and outputting data to and from the device 11;
13 is a processor having a simulation execution means 14; This simulation execution means 14 is executed by a simulation execution program of a processor.

The extended storage device 11 is managed based on the track capacity of a virtual disk device, which is divided by the dotted line in the figure, and each partition stores one track's worth of data in a format similar to that of a magnetic disk device. Ru.

The main storage device 10 is also provided with a plurality of track image buffers 15 having a capacity equal to the capacity of one track, that is, a partition of the extended storage device 11. Data input/output is performed in track units at high speed between the extended storage device 11 and the track image buffer 15 on the main storage device 10.

2 to 5 are flowcharts showing an example of virtual disk simulation processing performed by the simulation execution means 14, in which FIG. 2 is a seek process, FIG. 3 is a search process, FIG. 4 is a write process, and FIG. The figures each show the processing performed at the end of the simulation of the channel program.

When rewriting data on the virtual disk device, the simulation execution means 14 uses a channel program given by an object program, for example, a seek, search, write channel program, or a channel program that rewrites data of two consecutive records. Simulates the seek, search, write, and write channel programs, etc., and executes the same seek, search, write, etc. when reading data from the virtual disk device.
Implement simulations that match channel programs such as leads. Simulation is similarly performed when commands other than seek, search, read, and write are given, but in the following explanation, only the simulation processing related to the above commands will be explained.

In FIG. 1, a simulation of rewriting data on an extended storage device 11 used as a virtual disk device is performed, for example, as follows. That is, the simulation execution means 14 first
As shown in the figure, a search is made to see if there is a track image buffer on the main memory 10 that holds the contents of the track with the number specified by the seek command (S1), and if there is, the specified track is noted. Then, the seek process ends and the process moves to the next search process (S2, S7). However, if the designated track is not found in any of the current track image buffers, an appropriate track image buffer to be used to access the target track is selected (S3). Then, check whether the contents of the selected track image buffer have been updated but are not reflected in the extended storage device 11.
For example, the determination is made by referring to the identification flag provided for each track image buffer (S4), and if the flag is reflected, the content of the track specified for this selected track image buffer is determined, for example, by the arrow 302 in FIG. As shown in FIG. 7, the contents of the selected track image buffer are transferred from the extended storage device 11 (S6), and if they are not reflected, the contents of the selected track image buffer are transferred to the
As shown in 01, the content of the track specified in the selected track image buffer is written to the corresponding part of the extended storage device 11 and the identification flag corresponding to the track image buffer is reset (S5). Transfer from the extended storage device 11 as shown by arrow 302 in the figure (S6), and
The process moves to step S7.

In the search process, for example, as shown in FIG. 3, the simulation execution means 14 first searches for the record specified by the search command on the track image buffer that holds the track of interest (S10).
If the designated record is found, the search processing is ended with attention focused on the found record, and the process moves to read processing (S11, S19). On the other hand, if it is not found, search for a track image buffer that holds a track with the next track number of the track you are currently focusing on (S12), and if it is found, shift your attention to this next track and return to step S10 to repeat the above steps. A search for similar records is performed (S13, S18). If there is no more,
An appropriate track image buffer to be used to access the next track is selected (S14), and even though the contents of the selected track image buffer have been updated, they are not reflected in the extended storage device 11. The content of the next track is determined by the identification flag corresponding to that track image buffer (S15), and if it is reflected, the contents of the next track are transferred to this selected track image buffer (S17), and if it is not reflected, this track image buffer is The contents of the selected track image buffer are stored in the extended storage device 11.
After writing to the corresponding portion and resetting its identification flag (S16), the contents of the next track are transferred from the expanded storage device 11 to the selected track image buffer (S17), and the process moves to step S18.

In the write process, the simulate execution means 14 performs the process shown in FIG. 4, for example, and as shown by the arrow 303 in FIG. Rewrite with the contents of WBF1,
The identification flag corresponding to this track image buffer is reset (S20). Then, focusing on the next record, the write process ends (S21). if,
If the channel program includes consecutive write commands such as SHIK, SEARCH, WRITE, and WRITE, the write process shown in Figure 4 is executed again following the previous search process, and the write command of the record next to the record rewritten in step S20 is executed again. For example, the arrow 304 in FIG.
As shown in FIG. 2, the process of rewriting the buffer WBF2 with the contents specified by the subsequent write command is performed. Note that if the record to be rewritten by the subsequent write command is different from the track to which the record rewritten by the previous write command belongs, the target track can be moved to a track image back using the same method as explained for seek processing and search processing. Secure it on the front door and proceed with the process.

Next, a simulated operation when reading data from the extended storage device 11 used as a virtual disk device will be described. Channel programs for reading data from a virtual disk device include, for example, seek, search, read, etc., and the simulate execution means 14 executes the seek process in FIG. 2 and the search process in FIG. 3 in the same way as the rewriting process described above. Then, the record specified by the search command is searched on the track image buffer. Note that in this seek and search processing, as in the case of rewriting, if there is no track image buffer that holds the contents of the track of interest or there is no track image buffer that contains the record that is to be found, the predetermined location of the extended storage device 11 is If the contents of the track are transferred to the appropriate track image buffer, and the contents of the track originally stored in the track image buffer have been updated but are not reflected in the extended storage device 11, the above will occur. Before the transfer, processing is performed to transfer the contents of the track image buffer to the corresponding portion of the extended storage device 11. When the record specified by the seek and search processing is found, the read processing transfers the data of the record found by the search command to the buffer specified by the read command.

Now, when the simulation execution means 14 finishes the simulation processing of the channel program as described above, if there is a track image buffer whose identification flag is set as shown in FIG. For example, as shown by the arrow 305 in FIG. 6, the data is transferred to the corresponding portion of the extended storage device 11, and the corresponding identification flag is reset (S30). As can be seen from this process, even if the write command is a continuous channel program, the contents of the track image buffer are not reflected to the extended storage device every time one write command is processed.
Reflection processing is performed when the channel program ends.

As can be seen from the processing shown in FIGS. 2 and 3, even after the simulation of the command sequence is completed, the latest state of the tracks of the virtual disk device is maintained in the plurality of track image buffers 15, and the next Since these are referred to in the simulation, efficient simulation is possible in this respect as well. Furthermore, since the contents of the track image buffer are reflected in the extended storage device 11 when the simulation of the channel program ends, data loss in the event of a system failure is prevented.

〔Effect of the invention〕

As explained above, the present invention maintains the latest image of tracks in an extended storage device used as a virtual disk device during a track image buffer on the main storage device, and simulates the operation of the disk device when accessing the virtual disk device. When doing so, data reference operations necessary for access such as search, read, and write operations are performed on the track image buffer, and input/output between the extended storage device and the track image buffer is performed on a track-by-track basis. Therefore, the number of inputs and outputs between the main storage device and the extended storage device can be reduced accordingly, and furthermore, the track contents can be read from the extended storage device to the track image buffer by either track image buffer. This is done when the contents of the track you need are not retained.
Track contents are written from the track image buffer to the extended storage device only when the contents held in the track image buffer are changed to other track contents and when the simulation for the virtual disk device is completed, and the track contents are retained until then. This is done when the contents of a track that has been updated have not been reflected in the expanded storage device, so the number of inputs and outputs between the expanded storage device and the track image buffer can be reduced. Therefore, it is possible to perform simulation processing at high speed by minimizing the number of inputs and outputs between the extended storage device and the track image buffer while preventing data loss in the event of a system failure.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a main part showing an example of an information processing device to which the present invention is applied, FIG. 2 is a flowchart showing an example of a seek process performed by the simulation execution means 14, and FIG. 3 is a search process performed by the simulation execution means 14. FIG. 4 is a flow chart showing an example of a write process performed by the simulate execution means 14. FIG. 5 is a flow chart of a process performed by the simulate execution means 14 at the end of simulation of a channel program. FIG. 6 is a flow chart showing an example of a write process performed by the simulate execution means 14. FIG. 7 is an explanatory diagram of the rewriting operation of the device, and FIG. 7 is an explanatory diagram of the control method when the extended storage device 5 is used as a virtual disk device. In the figure, 10 is a main storage device, 11 is an expanded storage device, 12 is a transfer means, 13 is a processor, 1
4 is a simulation execution means, and 15 is a track image buffer.

Claims (1)

[Claims] 1. In a virtual disk control method for an expanded storage device in an information processing device having a main storage device and an expanded storage device capable of data transfer between the main storage device, the data format on the expanded storage device is changed to a magnetic disk device. In order to control the virtual disk of the extended storage device so that the expanded storage device can be accessed as a virtual disk device according to the data format of A plurality of track image buffers are provided to hold the data, and when simulating the operation of a magnetic disk device when accessing a virtual disk device, data reference operations necessary for access are performed on the track image buffer, and the data reference operation necessary for access is performed on the track image buffer. Input/output to/from the extended storage device is performed on a track-by-track basis, and track contents are read from the extended storage device to the track image buffer when the required track contents are not held in any of the track image buffers. The writing of track contents from the track image buffer to the extended storage device is performed when changing the contents held in the track image buffer to another track contents and when simulating a channel program for a virtual disk device. The extended storage device is characterized in that the processing is performed when the track is completed and the content of the track held until then is not reflected in the expanded storage device even though it has been updated. Virtual disk control method.