JP3125634B2 - Electronic computer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system having a disk cache, and more particularly to a computer system to which a disk cache can be easily added.

[0002]

2. Description of the Related Art A conventional control method of a disk cache system having a magnetic disk storage device and a cache memory is such that a cache memory is provided inside a magnetic disk storage device, and the cache memory control is performed within the same device. Such as a method of installing a dedicated disk cache device provided with a controller for performing cache control or a controller for performing cache control between the computer and the magnetic disk storage device. Mainly by hardware technology means.

Japanese Patent Application Laid-Open Nos. 63-066761 and 3-22445 relate to battery backup and data integrity of a cache memory provided in a magnetic disk storage device.
Japanese Patent Publication No. 045 describes a battery backup of a cache memory in a disk cache dedicated device and data integrity, and both relate to hardware technology.

When a disk cache system is realized by software means, any one of a main memory, a non-volatile memory, and a volatile memory with a battery for power backup is used as a cache memory, and the cache memory and the magnetic disk are used. Writing / reading to / from the storage device is controlled by a control program for the magnetic disk storage device.

[0005]

When a disk cache system is realized by hardware, a dedicated device is often added to make the system expensive, and a magnetic disk storage device itself has a cache memory. In this case, the magnetic disk storage device conventionally used in the computer system must be replaced with a magnetic disk storage device that can use a cache memory.

[0006] Even when a disk cache system is realized by software means, there are the following disadvantages. When the main storage device is used as a cache memory, it is necessary to prepare a large-scale backup battery capable of guaranteeing power supply to the entire electronic computer system, resulting in an expensive system. Also, if the CPU itself writes / reads data to / from the cache memory, there is a risk that a system which has conventionally been an I / O bottleneck for a so-called magnetic disk storage device may become a CPU bottleneck.

When a control program for a magnetic disk storage device is involved in cache memory control, an electronic computer system that uses a control program for a magnetic disk storage device that does not perform cache memory control uses a disk cache. It must be replaced by an operating system that can have memory control.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to add a software control means and a memory device having a battery for power supply backup and a volatile memory to use as a disk cache, thereby reducing hardware cost, Provided is an electronic computer system to which a disk cache can be added by using a disk cache control means which can be easily incorporated without replacing an operating system.

Therefore, the primary and secondary memories of the present invention
Device and an input / output bus for connecting the input / output devices.
Slave computer, and the device control means for controlling the input and output information device identified by the device number assigned to each of the input and output devices connected to the entering output bus, included in the output request of the application processing unit device An object-oriented operation control means comprising: a device control means search table for associating a number with a device control means; and a means for searching the device control means search table by a device number and activating the corresponding device control means.
In a computer system operated on a primary storage device , a volatile memory serving as a cache storage for the magnetic disk storage device of the secondary storage, a battery for backing up a power supply of the volatile memory when power is turned off, and a charge state of the battery are stored. Detecting means for controlling data transfer between the main memory as a primary storage and the volatile memory;
A memory device having MA data transfer means connected to the input / output bus; a memory device control means added to the operation control means for controlling input / output to / from the memory device; In response to an I / O request to a disk storage device, the memory device is operated as a cache storage of the magnetic disk storage device, and a write-back data is transferred from the cache storage to the magnetic disk storage device via the main storage device. characterized by comprising a disk cache control means is added to said operation control means for controlling the input and output information to be generated trigger of <br/> over data transfer and the data transfer, the disk cache comprising by .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

Referring to FIG. 1 showing a functional configuration of an embodiment of the present invention, a memory device 12 for a disk cache is shown.
0, the memory device 120 and the magnetic disk storage device 1
The operation of the computer 103 having the input / output bus 101 connecting the device 02 is controlled by the operation control means 110. Operation control means 110
Includes a magnetic disk storage device control unit 111 that controls input / output of the magnetic disk storage device 102. The input / output request 133 from the higher-level application processing unit 112 to the magnetic disk storage device 102 includes the device number of the magnetic disk storage device 102. In this embodiment, when the operation control means 110 does not have the disk cache control means 130 and the memory device 120 and there is the request 133, the operation control means 110 makes the device control means search table 113 and the input / output request 133 Then, the magnetic disk storage device 102 is identified from the device number included in the command and the input / output request is passed to the magnetic disk storage device control unit 111. The magnetic disk storage control unit 111 receives the input / output request 139
, An input / output request 140 is made to the magnetic disk storage device 102, and read / write input / output 137 and 138 are performed via the input / output bus 101.

[0012] As shown in FIG. 1, in the computer system 100 having a disk cache disk cache control unit 1 3 0 and the memory device control unit 131 and memory device 120 is added to the operation control unit 110, The memory device 120 includes a volatile memory 121 having a backup battery 122,
The backup battery 122 includes a backup battery state-of-charge confirmation unit 123 for detecting the state of charge of the backup battery 122 from the operation control unit 110, and a DMA controller 124 for performing a DMA transfer between a main storage device (not shown) and the volatile memory 121. The memory device 120 can directly input / output 136 from the application processing means 112 to the volatile memory 121 through the memory device control means 131.

[0013] Next operations controller 110, instrumentation <br/>置制disk cache a portion corresponding to the unit number of the magnetic disk storage device 102 of the control unit searches the table 113
The control means 130 is rewritten with information specifying itself. By the rewriting, an input / output request 133 from the application processing unit 112 to the magnetic disk storage device 102 is issued.
Is passed to the disk cache control unit 130 instead of the magnetic disk storage device control unit 111 .

The application processing means 112 sends a write I / O request 13
3, the disk cache control means 130
The data of the request 133 is not written directly to the magnetic disk storage device 102 through the magnetic disk storage device control means 111, but is written to the volatile memory 121 through the memory device control device 131. Disk cache control unit 130, data asynchronously with the operation of the application processing unit 112, the data of the volatile memory 121 by the DMA de <br/> over data transfer, a main memory <br/> from the volatile memory 121 Transfer and control means 111
To the magnetic disk storage device 102 through The application processing means 112 is the magnetic disk storage device 1
When a read I / O request 133 is made to 02, the disk cache control unit 130 determines whether or not the requested data exists in the volatile memory 121 with reference to a cache management table (not shown). If there is the data, and passes the data in the volatile memory 121 to load the application processing unit 112 to the main memory through the memory device control unit 131. If the requested data does not exist in the volatile memory 121, the disk cache control unit 130 reads the data of the magnetic disk storage device 102 into the main storage device through the magnetic disk storage device control unit 111, and the application processing unit 112
Hand over to

When the power supply is cut off due to a normal stoppage of the operation of the electronic computer 103, all data not yet written to the magnetic disk storage device 102 of the volatile memory 121 is transferred to the main storage device by the DMA controller 124 through the memory device control means 131. The data is read and written to the magnetic disk storage device 102 through the magnetic disk storage device control unit 111.

When the operation of the computer 103 is started, the disk cache control means 130 checks the charge state of the volatile memory backup battery 122 by the volatile memory backup battery charge state confirmation means 123, and When the battery 122 is still able to supply power, the volatile memory 121
It is checked whether or not there is any data yet to be written to the magnetic disk storage device 102, and if there is any unwritten data, the data is read into the main storage device by the DMA controller 124, and the magnetic disk storage device control program 111 To the magnetic disk storage device 102 through When there is a write I / O request 133 from the application processing unit 112 to the magnetic disk storage device 102, the disk cache control unit 130 writes the data to the volatile memory 121.

Next, the device control means search table 113
If, the input-output request 133,134,139,140, a magnetic disk storage device controller 1 11, a memory device control unit 131, a disk cache control unit 130,
This embodiment will be described with reference to FIGS. First, the functional configuration shown in FIG. 2 is a memory device control means 131 and a disk cache control 13 which are components for operating the disk cache of the present invention.
In a state where 0 is not added, that is, in a normal state of the computer 103 having no disk cache, the device control unit search table 220 and the input / output request for the magnetic disk storage device 102 and the magnetic disk storage device control unit 111 Indicates association. The input / output request structure 200 is created by the application processing unit 112 or the operation control unit 210 every time a write / read request to the various storage devices is issued from the application processing unit 112, and is deleted when the input / output is completed. The input / output request structure 200 has a device number 20
1 and storage peripherals and out information 20 necessary for the input and output requirements such as a flag bit indicating the start position and the amount of data and input and another output of
Contains 2. The device number 201 is a numerical value that is assigned in advance to all storage devices and input / output devices on a one-to-one basis and can specify the device.

The device control means search table 220 is a one-dimensional array storing the call addresses of the device control means for controlling the corresponding device by using the device number as an index.
The read address of the magnetic disk storage device control unit 111 is stored at a location in the array corresponding to the device number of the magnetic disk storage device 102. When an input / output request is issued from the application processing unit 112 to the magnetic disk storage device 102, the operation control unit 210 refers to the device number 201 in the input / output request structure 200, and the device control unit search table corresponding to the device number 201 220
And calls the device control means. Since the device number of the magnetic disk storage device 102 is set in the device number 201, the call address of the magnetic disk storage device control unit 111 that controls the magnetic disk storage device 102 is obtained from the device control unit search table 220. , The operation control means 210 can call the control means 111. The called magnetic disk storage device control means 111 performs input / output to / from the magnetic disk storage device 102 according to the input / output information 202. In the object-oriented operation control means 110, when a higher-level control means such as an application processing means calls a lower-level control means in order to use a certain function, the details are different, but generally the indirect call as described above. Take the way.

[0019] Figure 3, by adding a memory device controller 1 31 and the disk cache control unit 130 to the functional configuration of FIG. 2, the device controller searches the table 113, the input-output request 133,134,139,140, Magnetic disk storage device control means 111, memory device control means 131,
The relation of the disk cache control means 130 is shown. Disk cache control unit 130, Opereshi
Appropriate timing for initialization processing of the
In, part of the arrangement of the device control means searches the table 113 corresponding to the unit number of the disk storage device 102, that is, the call address of the magnetic disk storage device controller 111
After storing the call address storage area 132 of the magnetic disk storage device control unit 111, places the disk cache array of the device control means searches the table 113 corresponding to the unit number of the magnetic disk storage device 102 control means 13
Rewrite with a call address of 0. Memory device 120
Has a device number because it is input and output device, the position of the array of device control means search cable 113 corresponding to the device number call address of the memory device control means 13 1 is stored by the operation control means 110.

In the above state, when an input / output request is issued from the application processing means 112 to the magnetic disk storage device 102, the operation control means 110
Refers to the device number 201 in the input / output request structure 200, finds the location of the array in the device control means search table 113 corresponding to the device number 201, and calls the device control means. The device number 201 includes the magnetic disk storage device 102
The device cache number of the disk cache control unit 1 is set in the array corresponding to the device number of the magnetic disk storage device 102 in the device control unit search table 113.
Since the call address of the disk cache control means 130 is obtained, the operation control means 110 obtains the call address of the disk cache control means 130.
30 is called. The called disk cache control means 130 analyzes the input / output information 202 and creates an input / output request structure 300 for calling a lower-level device control means. When it is necessary to make an input / output request to the memory device 120 during the cache processing, the operation control means 110
Calls the memory device control means 131 and makes an input / output request to the magnetic disk storage device 102, by referring to the call address storage area 132 of the magnetic disk storage device control device 111, Call.

Next, management of read or write data will be described.

Volatile memory 121 in memory device 120
Referring to FIG. 4 showing a storage area divided into blocks, the volatile memory 121 is divided into a management area 410 and a data area 420. Next, the data area 420 is divided into cache blocks 421 to 42n which are management units of cache data. The write data to the magnetic disk storage device 102 is divided into cache blocks, and the cache blocks 421 to 42n
And is subjected to data transfer by cache control. Management unit Bed click 4 for storing management information corresponding to the management area 410 in the cache block 421 to 42n
Divide into 11 to 41n. In other words management unit blanking click 411
Stores the management information of the cache block 421, and the management unit block 41n stores the management information of the cache block 42n. In each management unit block 41n, a flag bit 41n-10 indicating a cache block state, a device number of the magnetic disk storage device, a start position of a storage area of the magnetic disk storage device, a valid data length, and the like are written to the magnetic disk storage device 102. And the cache information 41n-20 necessary for the storage.

In the flag bit 41n-10, the write data to the magnetic disk storage device 102 exists in the corresponding cache block, and the magnetic disk storage device 1
Dirty bit 41 indicating that data has not been written to 02
n-11 is provided. When a write request to the magnetic disk storage device 102 is received, the disk cache control unit 111 transfers the data of the request to a cache block (free cache block) 42 n in which valid data is not written by the memory device control unit 131. After the writing, the memory device 120 itself writes the management information of the data into the management block 41n without passing through the memory device control means 131 after the completion of the writing, the flag bit 41
The n-th dirty bit 41n-11 is turned ON, and the completion of writing is notified to the upper memory device control means 131 .

The disk cache control means 130
Then, LRU (Least Recent Sensation Used)
Dirty bit 41n-11 is turned on using a method such as
The management blocks 411 to 41n are managed, and when the number of free cache blocks falls below a certain number or when the operating load of the magnetic disk storage device 102 is low, the data is written to the cache block 42n. Data that has not been written to the magnetic disk storage device 102 is written to the magnetic disk storage device 102. Disk cache control unit 130 is a cache block DMA configuration write data to the magnetic disk storage device 102 on through the memory device control means 131 42n controller 124
The data is read into the main storage device, the data is referred to the cache information 41n-20, the data is written to the magnetic disk storage device 102 through the magnetic disk storage device control means 111, and the dirty bit 4 of the flag bit 41n-10 is read.
1n-11 is turned off. When the power is cut off due to the normal operation stop of the computer 103, the dirty bit 41n-11 is set to O in preparation for a long-time operation stop (power-off state).
The unwritten data of the N-th cache block is written to the magnetic disk storage device 102 in the same manner as described above.

At the start of operation when the computer system 100 is powered on, the disk cache control means 130
It is by first volatile memory backup battery charge status confirmation unit 123 of the memory device 120, a volatile main
The state of charge of the memory backup battery 122 is checked, and the volatile memory backup battery 122 can supply power to the volatile memory 121, and the volatile memory 121
Management data 411 if the data can be guaranteed.
To check all 41n-10 flag bits,
The unwritten data of the cache block 42n in which the dirty bit 41n-11 is ON to the magnetic disk storage device 102 is read into the main storage device by the DMA controller 124, and the cache information 41n-20 of the data is referred to. After writing to the magnetic disk storage device 102 through the disk storage device control means 111, the dirty bit 41n-11 of the flag bit 41n-10 is finally turned off. If the data contents of the volatile memory 121 cannot be guaranteed, the disk cache control unit 130 notifies the administrator of the computer system 100 of the magnetic disk storage by displaying the fact on the system console terminal. Device 102
Notify that data recovery is required.

[0026]

As described above, according to the present invention, it is possible to make use of the conventional hardware / software resources without replacing the hardware configuration and the operation control means of the operating computer system, thereby making it relatively inexpensive. In addition, a disk cache can be added to a computer system without compromising the data integrity of a magnetic disk storage device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a functional configuration of an embodiment of the present invention.

FIG. 2 is a diagram for explaining the relationship between a device control unit search table, an input / output request, and a magnetic disk storage device control unit;

FIG. 3 is a diagram for explaining a relationship between a device control means search table and input / output requests, and a magnetic disk storage device control means, a memory device control means, and a disk cache control means.

FIG. 4A is a diagram illustrating an area division of a volatile memory in a memory device, and FIG. 4B is a diagram illustrating a management unit block.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 computer system 101 input / output bus 102 magnetic disk storage device 103 electronic computer 110 operation control means 111 magnetic disk storage device control means 112 application processing means 113 device control means search table 120 memory device 121 volatile memory 122 volatile memory backup Battery 123 Volatile backup battery charge state checking means 130 Disk cache control means 131 Memory device control means

Continuation of the front page (56) References JP-A-6-348599 (JP, A) JP-A-1-150953 (JP, A) JP-A-62-58351 (JP, A) JP-A-3-71221 (JP) JP-A-6-44012 (JP, A) JP-A-5-11937 (JP, A) JP-A-4-247514 (JP, A) JP-A-3-286237 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G06F 12 / 08,3 / 06,3 / 08

Claims (3)

(57) [Claims] 1. A computer having input and output bus connecting device and output device of the primary and secondary storage are identified by device number assigned to each of the input and output devices connected to the entering output bus Device as input / output information
Therefore, the device control means for controlling, the device control means search table for associating the device number included in the input / output request of the application processing means with the device control means, and the device control means for searching the device control means search table by the device number and corresponding Operating the object-oriented operation control means on the primary storage device.
A volatile memory that is a cache storage for the magnetic disk storage device of the secondary storage, a battery that backs up a power supply of the volatile memory when power is cut off, a unit that detects a charge state of the battery, DMA for controlling data transfer between a main storage device as storage and the volatile memory
A memory device having data transfer means and connected to the input / output bus; a memory device control means added to the operation control means for controlling input / output to / from the memory device; and a magnetic disk from the application processing means. In response to an input / output request to a storage device, the memory device is operated as a cache storage of the magnetic disk storage device, and data transfer of write-back from the cache storage to the magnetic disk storage device via the main storage device is performed. In addition, the input / output information indicates that the data transfer is to be triggered.
And a disk cache control means added to the operation control means for controlling the computer cache. 2. The data transfer start timing generated by the disk cache control means is when the data in the disk cache reaches a predetermined amount or when the operating load of the magnetic disk storage device falls below a predetermined amount.
2. The computer system according to claim 1, wherein: 3. The input / output information, In the main storage device, the input / output operation held for the device
Required control information, Device number, storage device start position, data amount, Entering
A flag indicating force or output.
The computer system according to claim 1.