JPH06236240A - Magnetic disk system - Google Patents

Abstract

PURPOSE:To save the cost and space for installing sub system magnetic disk device by duplexing a magnetic disk device by mixing the data of two main system magnetic disk devices and writing those data in one sub system magnetic disk device. CONSTITUTION:The write data of two main system magnetic disk devices Eik and Fik are mixed by exclusive OR at a data mix/restoration part 5 and written in a correspondent sub system magnetic disk device Gik corresponding to the contents of a unit address translation table 15 stored in a storage part 7. When reading is disabled since any fault is generated at the main system magnetic disk device Eik, for example, the data of the main system magnetic disk device Eik can be restored from the read data of the main system magnetic disk device Fik and the sub system magnetic disk device Gik by the exclusive OR at the data mix/restoration part 5. Thus, two main system magnetic disk devices EF can be duplexed by one sub system magnetic disk device G.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk system.

[0002]

2. Description of the Related Art FIG. 17 is a block diagram showing an example of a partial configuration of a conventional computer system.

In the central processing unit 1, j (j is an integer of 1 or more)
A set of magnetic disk systems DK1 to DKj are connected. Arbitrary magnetic disk system DKi (i is 1 ≦ i
≤ j) is roughly classified into a magnetic disk controller DC
i, and n (n is an integer of 1 or more) magnetic disk devices Di1 to Din and n magnetic disk devices di1 to din connected to i. Further, the magnetic disk device is duplicated with a primary magnetic disk device D and a secondary magnetic disk device d.

FIG. 18 shows the magnetic disk system D of FIG.
It is a block diagram which shows the detail of Ki.

The magnetic disk controller DCi has a central processing unit 16 for controlling the overall operation, a command / data receiving unit 3 for receiving commands and data from the central processing unit 1, and a response and data for the central processing unit 1. , A write data buffer 9 for storing data to be written to the primary magnetic disk device D or the secondary magnetic disk device d, and a read data buffer 9 for reading from the primary magnetic disk device D or the secondary magnetic disk device d. Control for generating a unit address signal UA, a cylinder address signal CA, a head address signal HA, a write command signal WG, and a read command signal RG by a command from the central processing unit 16. It is composed of a signal generator 11.

FIG. 19 is a flow chart for explaining the data writing process of the central processing unit 1 of FIG. FIG. 20 is a flow chart for explaining the data reading process of the central processing unit 1 of FIG. 21 to 23 are shown in FIGS.
6 is a flowchart for explaining details of the operation (step S2, step S8) of the magnetic disk controller DCi shown in FIG. FIG. 24 shows the magnetic disk device Di shown in FIG.
It is a flow chart for explaining the details of the device selection operation of k (step Sc4). FIG. 25 shows a data write operation of the magnetic disk device Dik shown in FIG. 22 (step Sc1
It is a flow chart for explaining the details of 0). FIG. 26 is a flow chart for explaining the details of the data reading operation (step Sc15) of the magnetic disk device Dik shown in FIG.

Next, the operation when the central processing unit 1 writes data to an arbitrary magnetic disk device Dik (k is an integer 1 ≦ k ≦ n) will be described with reference to FIGS. 18, 19 and 21 to 25. explain.

The central processing unit 1 sends a command instructing writing and data to the magnetic disk controller DCi (step S1). To this command, a unit address for selecting a magnetic disk device to which data is to be written, a cylinder address indicating a writing position, and a head address are added.

The magnetic disk controller DCi starts its operation upon receiving the command and data (step S).
2).

Details of step S2 are shown in FIGS. 21 to 23 and will be described with reference to these figures.

Command of the magnetic disk controller DCi
The data receiving unit 3 holds the command and data received from the central processing unit 1 (step Sc1). The central processing unit 16 analyzes the command held in the command / data receiving unit 3 (step Sc2) and instructs the control signal generating unit 11 to output the unit address signal UA (step Sc3). The unit address signal UA is composed of a combination of bits and is a signal used for selecting the magnetic disk device. Magnetic disk device Dik
Starts the device selecting operation when the unit address signal UA is input (step Sc4).

Details of step Sc4 are shown in FIG. 24, and will be described with reference to this figure.

The unit address signal UA is input to all the magnetic disk devices Di1 to Din and di1 to din connected to the magnetic disk control device DCi (step Ss1). Magnetic disk devices Di1 to Din, d
A unique unit address is set to each of i1 to din, and the unit address indicated by the unit address signal UA is compared with the unit address of the own device (step Ss2), and the matched magnetic disk device Dik
Only outputs the status notification signal ST to notify the status of the device to the magnetic disk controller DCi (step Ss).
3). The status notification signal ST is composed of a combination of bits, and indicates whether the magnetic disk device is in an operable state or an inoperable state, whether it is in operation or in operation, whether there is an error, and if an error has occurred, the It is a signal used to notify the contents. Magnetic disk devices Di1 to Din, di1 to din other than the magnetic disk device Dik
Does not output the status notification signal ST. With this, the device selection operation of the magnetic disk device Dik of FIG. 21 (step Sc4)
Ends.

Returning to the operation of the magnetic disk controller DCi shown in FIG. 21, the description will be continued.

The central processing unit 16 inputs the state notification signal ST (step Sc5), judges the content thereof (step Sc6), and if the content indicates the inoperable state, inputs the state notification signal again (step). Sc5), wait until it becomes operable. If the content of the state notification signal ST indicates the operable state, the command type analyzed in the above (Step Sc2) is judged (Step Sc7), and if it is the command to instruct the writing, the command / data receiving unit 3 is transferred to the write data buffer 9 (step Sc8), and the control signal generator 11 is instructed to output the cylinder address signal CA, the head address signal HA, and the write command signal WG (step Sc9). ). The cylinder address signal CA and the head address signal HA are composed of a combination of bits, and are signals used for selecting an address on the magnetic disk which is a target for writing or reading data.

The magnetic disk device Dik starts a data write operation when the write command signal WG is input (step Sc10).

Details of step Sc10 are shown in FIG. 25, and will be described with reference to this figure.

Write data WD, cylinder address signal CA, head address signal HA, and write command signal W
G means the magnetic disk devices Di1 to Din, di1 to d
Although input to in (step Sw1), the magnetic disk devices other than the magnetic disk device Dik with which the unit address signals UA match are ignored. The magnetic disk device Dik notifies the magnetic disk controller DCi that it is operating by the status notification signal ST (step Sw2), and writes data WD to the address indicated by the cylinder address signal CA and the head address signal HA.
The content of is written (step Sw3). Upon completion of the write operation, the magnetic disk device Dik determines whether or not an error has occurred (step Sw4), and if there is no error, adds information indicating no error to the status notification signal ST (step Sw5). Adds the information indicating the presence of an error and the content of the error to the status notification signal ST (step Sw6), and notifies the magnetic disk controller DCi of the operation end by the status notification signal ST (step Sw6).
7).

This completes the data writing operation (step Sc10) of the magnetic disk device Dik of FIG.

Returning to the operation of the magnetic disk controller DCi shown in FIG. 22, the description will be continued.

The central processing unit 16 is a magnetic disk device Di.
The status notification signal ST is input from k (step Sc1
1) The contents are judged (step Sc12), and if the contents indicate that the operation is in progress, the state notification signal ST is input again (step Sc11) and the operation is awaited. When the content of the state notification signal ST indicates the end of the operation, the response of the end of the operation is transmitted to the central processing unit 1 via the response / data transmitting unit 4 (step Sc13). The response includes the presence / absence of an error included in the status notification signal ST and, if there is an error, the content thereof.

Now, the magnetic disk controller DC of FIG.
The operation of i (step S2) ends.

Returning to the data writing process of the central processing unit 1 of FIG. 19, the continuation will be described.

The central processing unit 1 receives the response from the magnetic disk controller DCi (step S3), judges the presence or absence of an error from the contents (step S4), and if it indicates that there is an error, the central processing unit 1 The processing device 1 performs the write error restoration process (step S5), and when it indicates that there is no error, does not perform the write error restoration process.

In a general write error recovery process, if the data write process is retried and an error occurs even after retrying a certain number of times, the address is regarded as an unusable area and is not used thereafter. The method used is used. This alternative area can be secured on the disk in advance, or the address next to the address where the write error has occurred can be used.

The central processing unit 1 is a magnetic disk unit Di.
When the writing of data to k is completed, (step S
1 to step S5) the magnetic disk device Dik described in
Data is written to the magnetic disk device dik by the same procedure as the data writing operation to (step S6). The write data in this case is the same as the data written to the magnetic disk device Dik immediately before, and the write address is also the same.

By the above operation, the same magnetic disk device D and the secondary magnetic disk device d are always written with the same data.

Next, the operation when the central processing unit 1 reads the data from the magnetic disk device Dik is shown in FIG.
8, FIG. 20 to FIG. 24, and FIG. 26 will be described.

The central processing unit 1 sends a command instructing reading to the magnetic disk controller DCi (step S7). This command is added with a unit address for selecting a magnetic disk device from which data is read, a cylinder address indicating a read position, and a head address.

Upon receiving the command, the magnetic disk controller DCi starts its operation (step S8).

Details of step S8 are shown in FIGS. 21 to 23 and will be described with reference to these figures.

The magnetic disk controller DCi follows the same procedure as the description of the write operation described above.
k is selected (step Sc1 to step Sc6).

When the content of the status notification signal ST indicates the operable status, the central processing unit 16 executes the above-mentioned (step Sc
The command type analyzed in 2) is determined (step Sc
7), if it is a command to command a read,
The control signal generator 11 is instructed to output the cylinder address signal CA, the head address signal HA, and the read command signal RG (step Sc14). When the read command signal RG is input, the magnetic disk device Dik starts a data read operation (step Sc15).

The details of step Sc15 are shown in FIG. 26, and will be described with reference to this figure.

The cylinder address signal CA, the head address signal HA, and the read command signal RG are input to the magnetic disk devices Di1 to Din and di1 to din (step Sr1), but the unit address signal UA is the same. Magnetic disk devices other than Dik ignore this. The magnetic disk device Dik notifies the magnetic disk controller DCi that it is operating by the status notification signal ST (step Sr2), and reads the data at the address indicated by the cylinder address signal CA and the head address signal HA. (Step Sr3).
When the reading operation is completed, the magnetic disk device Dik
Whether or not an error has occurred is determined (step Sr4), and if there is no error, the read data RD is output, and information indicating no error is added to the status notification signal ST (step Sr4).
5) If there is an error, information indicating that there is an error and the content of the error are added to the status notification signal ST (step Sr).
6) Then, the status notification signal ST is used to notify the magnetic disk controller DCi of the end of the operation (step Sr7).

This completes the data reading operation (step Sc15) of the magnetic disk device Dik of FIG.

Returning to the operation of the magnetic disk controller DCi of FIG. 23, the continuation will be described.

The read data RD is stored in the read data buffer 10 of the magnetic disk controller DCi (step Sc16). The central processing unit 16 inputs the status notification signal ST from the magnetic disk device Dik (step Sc17), judges its content (step Sc18),
If the content indicates that the operation is in progress, the accumulation of the read data RD (step Sc16) is continued, the status notification signal ST is input again (step Sc17), and the operation is awaited. If the content of the status notification signal ST indicates the end of the operation, the response of the end of the operation and the read data buffer 10
The read data stored in the central processing unit 1 is transmitted to the central processing unit 1 via the response / data transmission unit 4 (step S
c19). The presence or absence of an error included in the status notification signal ST and the content of the error, if any, are added to this response.

Now, the magnetic disk controller DC of FIG.
The operation of i (step S8) ends.

Returning to the data reading process of the central processing unit 1 of FIG. 20, the continuation will be described.

The central processing unit 1 receives the response from the magnetic disk controller DCi (step S9), judges the presence / absence of an error from the contents (step S10), and when it indicates that there is no error, the magnetic Disk device Dik
The data reading process from is ended.

When the response indicates that there is an error, the central processing unit 1 performs a read error repairing process (step S11).

In a general read error repair process, the data read process is retried a certain number of times.

The result of the retry is judged (step S1
2), if the error recovery is successful, the magnetic disk device D
The data reading process from ik ends.

When the error recovery fails, the data reading process from the magnetic disk device Dik is stopped, and the same address of the other duplicated magnetic disk device dik will be described in the above (steps S7 to S11). The data is read by the same procedure as the data reading operation of the magnetic disk device Dik (step S13).

Even if the primary magnetic disk device D fails due to the above operation, or the data written in the primary magnetic disk device D is destroyed for some reason, the secondary magnetic disk device d can be normal. The data can then be used to keep the computer system running.

[0047]

In the case of duplicating the magnetic disk devices in the conventional magnetic disk system, the same number of secondary magnetic disk devices as the primary magnetic disk devices are required, and the introduction cost and the installation space are not duplicated. There was a problem that it would be required twice.

[0048]

In the magnetic disk system of the present invention, an even number of primary magnetic disk devices for storing information and one secondary system for every two primary magnetic disk devices are installed. A magnetic disk device, a command / data receiving unit for receiving commands and data from a central processing unit, a response / data transmitting unit for transmitting a response and data to the central processing unit, and writing to the secondary magnetic disk unit A data mixing / restoring unit for generating mixed data and restoring original data from the mixed data, a data holding unit for temporarily holding write data, and a virtual unit address given from the central processing unit to a real unit address. The storage unit that stores the unit address conversion table used for conversion and the contents of this unit address conversion table are updated. An operation unit used for the purpose, a write data buffer for storing data to be written in the primary magnetic disk device or the secondary magnetic disk device, and a read data buffer for storing data read from the primary magnetic disk device or the secondary magnetic disk device And a control signal generator for generating a unit address signal, a cylinder address signal, a head address signal, a write command signal, and a read command signal for the primary magnetic disk device and the secondary magnetic disk device, and the operation of all of them. And a magnetic disk controller constituted by a central processing unit for controlling the.

[0049]

Embodiments of the present invention will now be described with reference to the drawings.

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

The magnetic disk controller DWi of this embodiment
Is a central processing unit 2 that controls the overall operation, a command / data receiving unit 3 that receives commands and data from the central processing unit 1, and a response / data transmission unit that sends responses and data to the central processing unit 1. 4, a data mixing / restoring unit 5 for generating mixed data for writing to the secondary magnetic disk device G and restoring the original data from the mixed data, a data holding unit 6 for temporarily holding the write data, and a central unit. A storage unit 7 for storing a unit address conversion table 15 used for converting a virtual unit address given from the processing device 1 into a real unit address; and an operation unit 8 used for updating the contents of the unit address conversion table 15. A write data buffer 9 for storing data to be written in the primary magnetic disk device EF or the secondary magnetic disk device G; A read data buffer 10 for storing data read from the magnetic disk device EF or the secondary magnetic disk device G, and a unit address signal UA, a cylinder address signal CA, a head address signal HA, and a write command signal WG according to commands from the central processing unit 2. And a control signal generator 11 for generating a read command signal RG.

That is, the data mixing / restoring unit 5, the data holding unit 6, the storage unit 7, and the operation unit 8 are different from the conventional magnetic disk controller DCi (see FIGS. 17 and 18).

FIG. 2 is a block diagram showing details of the data mixing / restoring unit 5 of FIG. The data mixing / restoring unit 5 holds data buffers 12 and 13 for holding data input for mixing data or restoring data, and exclusive use of data held by the data buffers 12 and 13. Exclusive OR circuit 14 that outputs a logical sum
And have.

FIG. 3 is an explanatory diagram showing an example of the contents of the unit address conversion table 15 of FIG. In the conventional example, as described with reference to FIG. 18, the unit address added to the command transmitted by the central processing unit 1 and the unit address signal UA for selecting the primary magnetic disk device D and the secondary magnetic disk device d are Although there was a one-to-one correspondence, the present invention uses virtual unit addresses.

In FIG. 3, the virtual unit address string T
C1 is used as a unit address conversion key. If the content is "1", the sub system indicator column TC2 indicates that the unit address is the sub system magnetic disk device,
When it is "0", it indicates that it is a primary magnetic disk device. The real unit address string TC3 indicates the real unit address of the magnetic disk device corresponding to the virtual unit address string TC1. The first primary system real address column TC4 is valid only when the secondary system indicator column TC2 is "1" and indicates the real unit address of the primary magnetic disk device corresponding to the secondary magnetic disk device.

In the present invention, the data of two primary magnetic disk devices are mixed and written in the secondary magnetic disk device by the method described later, but the second primary real address string TC5 is the first primary real disk. The real unit address of the other primary magnetic disk device mixed with the data of the primary magnetic disk device indicated by the address column TC4 is shown. The second primary system real address sequence TC5 is valid only when the secondary system sequence column TC2 is "1".

FIG. 4 is a block diagram of a part of a computer system using the magnetic disk system of FIG.

To the central processing unit 1, j sets of magnetic disk systems DS1 to DSj are connected. The arbitrary magnetic disk system DSi is roughly classified into a magnetic disk controller DWi and n magnetic disk devices E connected thereto.
i1 to Ein and n magnetic disk devices Fi1 to Fin
And n magnetic disk devices Gi1 to Gin. The magnetic disk device is the primary magnetic disk device E.
F and the secondary magnetic disk device G are duplicated.

That is, one in two primary magnetic disk drives EF
It is different from the conventional magnetic disk system DKi in that the secondary magnetic disk devices G are installed in proportion to the number of units.
5 and 6 are flowcharts for explaining the data writing process of the central processing unit 1 in FIG. 1, and FIGS. 7 and 8 are flowcharts for explaining the data reading process of the central processing unit 1 in FIG. 9 to 16 are flowcharts for explaining the details of the operation (step N2, step N7, step N12, step N18) of the magnetic disk controller DWi shown in FIGS. 5 to 8.

Next, the operation of this embodiment will be described with reference to FIGS.

Unit address conversion table 15 of FIG.
Means that the virtual magnetic disk unit EF of the primary magnetic disk unit EF paired with the secondary magnetic disk unit G of the virtual unit address "2" has the virtual unit address "0" and the virtual unit address "3" has the virtual magnetic unit G This is an example of a case where the virtual unit address of the primary magnetic disk device EF paired with is a "1".

First, the real unit address of the magnetic disk device Eik is "0", the real unit address of the magnetic disk device Fik is "1", the real unit address of the magnetic disk device Gik is "2", and the unit address conversion table 15 An operation of writing data to the secondary magnetic disk device G of the virtual unit address "2" when the content is as shown in FIG. 3 will be described.

The magnetic disk control device DWi selects the primary magnetic disk device EF or the secondary magnetic disk device G by the unit address signal UA, and the data by the cylinder address signal CA, the head address signal HA and the write command signal WG. Writing operation, cylinder address signal CA, head address signal HA, and read command signal R
Operation to read data with G and status notification signal ST
The operation for determining the state in step S6 is the same as that of the conventional magnetic disk controller DCi, magnetic disk device D, and magnetic disk device d in FIG.

The central processing unit 1 sends a command and data for instructing the writing of data to the secondary magnetic disk device G of the virtual unit address "2" to the magnetic disk control device DW.
It is transmitted to i (step N1). The magnetic disk control device DWi starts its operation upon receiving the command and the data (step N2).

Details of step N2 are shown in FIGS. 9 to 16 and will be described with reference to these figures.

Command of magnetic disk controller DWi
The data receiving unit 3 holds the command and data received from the central processing unit 1 (step Nc1). The central processing unit 2 analyzes the command held in the command / data receiving unit 3 (step Nc2), and from the unit address conversion table 15 using the virtual unit address "2" added to the command as a key, the subsystem Marker column TC2, real unit address column TC3, first primary system real address column T
C4 and the second real system real address sequence TC5 are read (step Nc3).

It is judged whether the subsystem flag column TC2 is "1" or "0" (step Nc4). If TC2 = 1, the virtual unit address is recognized as the subsystem magnetic disk device G, If TC2 = 0, it is recognized as the primary magnetic disk device EF. In this example, since TC2 = 1, the virtual unit address "2" is recognized as the secondary magnetic disk device G.

When the command type analyzed in the above (step Nc2) is judged (step Nc13) and the command is a command for writing, the data held in the command / data receiving part 3 is sent to the data holding part 6. Transfer (step Nc14). Second real system real address string TC5
As a unit address signal UA
ik is selected (step Nc15), data is read from the magnetic disk device Fik and stored in the read data buffer 10 (step Nc16). It is determined whether or not there is a reading error of the magnetic disk device Fik (step Nc17), and if there is no error, the data held in the read data buffer 10 is transferred to the data buffer 12 of the data mixing / restoring unit 5 (step). Nc1
8). The data held in the data holding unit 6 is transferred to the data buffer 13 (step Nc19), and the output data of the exclusive OR circuit 14 is written into the write data buffer 9
(Step Nc20).

Here, the data transferred to the write data buffer 9 are the data to be written to the secondary magnetic disk device G of the virtual unit address “2” received from the central processing unit 1 and the read data from the magnetic disk device Fik. It is the data that is mixed by exclusive OR. The magnetic disk device Gik is selected by using the real unit address string TC3 as a unit address signal UA (step Nc2
1), the mixed data is written in the magnetic disk device Gik (step Nc22), and a response of operation completion is transmitted to the central processing unit 1 (step Nc23). If there is an error in the determination as to whether or not there is an error in the reading of the magnetic disk device Fik described above (step Nc17), if there is an error, the operation of restoring the data of the magnetic disk device Fik from the data of the magnetic disk device Eik and the magnetic disk device Gik To do.

Next, from the data of the magnetic disk device Eik and the magnetic disk device Gik, the magnetic disk device Fik is used.
The operation of restoring the data will be described.

The magnetic disk device Gik is selected by using the real unit address string TC3 as a unit address signal UA (step Nc24), the data is read from the magnetic disk device Gik and stored in the read data buffer 10 (step Nc25). It is determined whether or not there is a reading error of the magnetic disk device Gik (step Nc26),
If there is no error, the data held in the read data buffer 10 is transferred to the data buffer 12 of the data mixing / restoring unit 5 (step Nc27). Next, the first primary system real address sequence TC4 is set to the unit address signal UA.
Select the magnetic disk device Eik as (step Nc
28), the data is read from the magnetic disk device Eik and stored in the read data buffer 10 (step Nc29).

It is judged whether or not there is a reading error of the magnetic disk device Eik (step Nc30), and if there is no error, the data held in the read data buffer 10 is transferred to the data buffer 13 of the data mixing / restoring unit 5. (Step Nc31), the data output from the exclusive OR circuit 14 is input to the data buffer 12 (step Nc32). Here, the data output from the exclusive OR circuit 14 is the restored magnetic disk device Fik.
Data.

If there is an error in the determination as to whether or not there is a read error in the magnetic disk device Gik (step Nc26) or the determination as to whether or not there is a read error in the magnetic disk device Eik (step Nc30), the virtual unit address " As a write error of the secondary magnetic disk device G of "2", a response of operation completion is transmitted to the central processing unit 1 (step Nc33).

By the above operation (steps Nc24 to Nc32), the data of the magnetic disk device Eik and the data of the magnetic disk device Gik are used to calculate the magnetic disk device Fi.
When the data of k is restored, the above-mentioned magnetic disk device Fi
Operation when there is no error in reading k (step Nc
19 to step Nc23). Now, the operation of the magnetic disk controller DWi in FIG. 5 (step N
2) ends.

Now, returning to the data writing process of the central processing unit 1 of FIG. 5, the description will be continued.

The central processing unit 1 receives the response from the magnetic disk control unit DWi (step N3), judges the presence / absence of an error from the content (step N4), and if it indicates that there is an error, the central processing unit 1 The processing device 1 performs the write error restoration process (step N5), and when it indicates that there is no error, does not perform the write error restoration process. Further, when the central processing unit 1 finishes the data writing process to the secondary magnetic disk device G of the virtual unit address “2”, it stores the virtual unit address “0” of the virtual magnetic disk device G paired with the secondary magnetic disk device G. The data writing process to the primary magnetic disk device EF is started. Primary magnetic disk device EF of this virtual unit address "0"
The contents of the data to be written to and the address to be written are the same as the data and the address written immediately before to the secondary magnetic disk device G of the virtual unit address “2”.

The central processing unit 1 sends to the magnetic disk controller DWi a command and data for instructing the writing of data to the primary magnetic disk unit EF of the virtual unit address "0" (step N6). The magnetic disk controller DWi starts its operation upon receiving the command and the data (step N7). Details of step N7 are shown in FIGS. 9 to 16 and will be described with reference to these figures.

Command of magnetic disk controller DWi
The data receiving unit 3 holds the command and data received from the central processing unit 1 (step Nc1). The central processing unit 2 analyzes the command held in the command / data receiving unit 3 (step Nc2), and uses the virtual unit address "0" added to the command as a key to convert the unit address conversion table 15 to the sub system. Marker column TC2, real unit address column TC3, first primary system real address column T
C4 and the second real system real address sequence TC5 are read (step Nc3).

It is judged whether the subsystem flag column TC2 is "1" or "0" (step Nc4). When TC2 = 1, the virtual unit address is recognized as the subsystem magnetic disk device G, If TC2 = 0, it is recognized as the primary magnetic disk device EF. In this example, since TC2 = 0, it is recognized that the virtual unit address "0" is the primary magnetic disk device EF. Real unit address string TC
3 is selected as the unit address signal UA and the magnetic disk device Eik is selected (step Nc5).
The command type analyzed in c2) is judged (step Nc
6), if it is a command to command a write,
The data held in the command / data receiving unit 3 is transferred to the write data buffer 9 (step Nc).
7). The data is written to the magnetic disk device Eik (step Nc8), and a response of operation completion is transmitted to the central processing unit 1 (step Nc9). This completes the operation (step N7) of the magnetic disk controller DWi in FIG.

Returning to the data writing process of the central processing unit 1 of FIG. 6, the description will be continued.

The central processing unit 1 receives the response from the magnetic disk control unit DWi (step N8), judges the presence or absence of an error from its contents (step N9), and if it indicates that there is an error, the central processing unit 1 The processing device 1 performs the write error restoration process (step N10), and when it indicates that there is no error, does not perform the write error restoration process.

By the operation described above (steps N1 to N10), the data mixed by the exclusive OR of the data of the magnetic disk device Eik and the data of the magnetic disk device Fik is written in the magnetic disk device Gik.

Next, the operation of the central processing unit 1 for reading data from the primary magnetic disk device EF of the virtual unit address "0" will be described.

The central processing unit 1 sends to the magnetic disk control unit DWi a command instructing to read data from the primary magnetic disk unit EF of the virtual unit address "0" (step N11). Upon receiving the command, the magnetic disk control device DWi starts its operation (step N12).

Details of step N12 are shown in FIGS. 9 to 16, and will be described with reference to these figures.

Command of magnetic disk controller DWi
The data receiving unit 3 holds the command received from the central processing unit 1 (step Nc1).

The central processing unit 2 analyzes the command held in the command / data receiving unit 3 (step Nc2),
The unit address conversion table 15 using the virtual unit address "0" added to the command as a key
From the sub system indicator column TC2 and the real unit address column TC3
Then, the first primary system real address sequence TC4 and the second primary system real address sequence TC5 are read (step Nc3). It is determined whether or not the sub system marker sequence TC2 is "1" or "0" (step Nc
4) In this example, since it is "0", it is recognized as the primary magnetic disk device EF. Real unit address string T
The magnetic disk device Eik is selected by using C3 as the unit address signal UA (step Nc5), and the command type analyzed in (step Nc2) is judged (step Nc).
c6), if the command is a command for reading, data is read from the magnetic disk device Eik (step Nc10). The content of the read data RD is accumulated in the read data buffer 10 (step Nc11),
When the reading is completed, the response of the operation completion and the read data are transmitted to the central processing unit 1 (step Nc12).

This completes the magnetic disk controller DWi of FIG.
Operation (step N12) is completed, the process returns to the data reading process of the central processing unit 1, and the continuation will be described.

The central processing unit 1 receives the response from the magnetic disk control unit DWi (step N13), judges the presence / absence of an error from the contents (step N14), and if it indicates that there is no error, the virtual processing is performed. The data reading process from the primary magnetic disk device EF of the unit address "0" is completed. If the response indicates that there is an error, the central processing unit 1 performs a read error recovery process (step N15).

The result of the read error repair processing is judged (step N16), and if the error repair is successful, the data read processing from the primary magnetic disk device EF of the virtual unit address "0" is terminated.

When the error recovery fails, the central processing unit 1 stops reading data from the primary magnetic disk device EF of the virtual unit address "0", and the secondary magnetic disk device G of the virtual unit address "2". From the magnetic disk controller D
It transmits to Wi (step N17). Upon receiving the command, the magnetic disk control device DWi starts its operation (step N18).

Details of step N18 are shown in FIGS. 9 to 16 and will be described with reference to these figures.

Command of magnetic disk controller DWi
The data receiving unit 3 holds the command received from the central processing unit 1 (step Nc1). The central processing unit 2 analyzes the command held in the command / data receiving unit 3 (step Nc2), and from the unit address conversion table 15 using the virtual unit address "2" added to the command as a key, the subsystem The marker column TC2, the real unit address column TC3, the first normal system real address sequence TC4, and the second normal system real address sequence TC5 are read (step Nc).
3).

It is judged whether the subsystem flag column TC2 is "1" or "0" (step Nc4), and since it is "1" in this example, the subsystem magnetic disk device G is recognized. The command type analyzed in step Nc2 is determined (step Nc13), and if the command is a command to read, the magnetic disk device Gik is selected using the real unit address sequence TC3 as the unit address signal UA (step Nc34). , Data is read from the magnetic disk device Gik and stored in the read data buffer 10 (step Nc35). Magnetic disk device Gik
Whether there is an error in reading (step Nc3
6), if there is no error, read data buffer 1
The data held in 0 is transferred to the data buffer 12 of the data mixing / restoring unit 5 (step Nc37).

Next, the magnetic disk device Fik is selected by using the second normal real address column TC5 as the unit address signal UA (step Nc38), and the magnetic disk device Fik is selected.
The data is read from and stored in the read data buffer 10 (step Nc39). Magnetic disk device Fi
It is determined whether or not there is an error in reading k (step Nc4
0), read data buffer 1 if there is no error
The data held in 0 is transferred to the data buffer 13 of the data mixing / restoring unit 5 (step Nc41), and the output data of the exclusive OR circuit 14 is read as data to the central processing unit 1 together with the response of the operation end. It is transmitted (step Nc42). Here, the data output from the exclusive OR circuit 14 is the restored magnetic disk device Eik.
Data.

If there is an error in the determination as to whether or not there is a read error in the magnetic disk device Gik (step Nc36) or the determination as to whether or not there is a read error in the magnetic disk device Fik (step Nc40), the virtual unit address " As a reading error of the secondary magnetic disk device G of "2", a response of operation completion is transmitted to the central processing unit 1 (step Nc43). This completes the operation (step N18) of the magnetic disk controller DWi in FIG.

Therefore, returning to the data reading process of the central processing unit 1 in FIG. 8, the description will be continued.

The central processing unit 1 receives the response from the magnetic disk control unit DWi (step N19), judges the presence or absence of an error from its contents (step N20), and if it indicates that there is an error, the central processing unit 1 The processing device 1 performs a read error recovery process (step N21). If the response indicates that there is no error, the data reading process from the secondary magnetic disk device G of the virtual unit address “2” is terminated.

Even if the data of the magnetic disk device Eik cannot be read by the operation described above (steps N11 to N21), the magnetic disk is obtained from the exclusive OR of the data of the magnetic disk device Fik and the data of the magnetic disk device Gik. The data of the device Eik can be restored.

Even if the central processing unit 2, the data mixing / restoring unit 5, the data holding unit 6, the storage unit 7 and the operating unit 8 are built in the central processing unit 1, the central processing unit 1 and the conventional magnetic disk can be used. It may be incorporated as an independent device in the middle of the control device DCi.

[0101]

As described above, according to the present invention, the data of two primary magnetic disk devices are mixed and written in one secondary magnetic disk device, so that the number of secondary magnetic disk devices can be increased. However, it has an effect that the introduction cost and the installation space can be saved.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing details of a data mixing / restoring unit in FIG.

FIG. 3 is an explanatory diagram showing an example of contents of a unit address conversion table of FIG.

4 is a block diagram of a part of a computer system using the magnetic disk system of FIG.

5 is a flowchart illustrating a data write process of the central processing unit 1 shown in FIG.

6 is a flowchart illustrating a data writing process of the central processing unit 1 shown in FIG.

7 is a flowchart illustrating a data reading process of the central processing unit 1 shown in FIG.

8 is a flowchart illustrating a data reading process of the central processing unit 1 shown in FIG.

FIG. 9 is a magnetic disk control device DW shown in FIGS.
i operation (step N2, step N7, step N1
2, a flow chart illustrating the details of step N18).

FIG. 10 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 11 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 12 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 13 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 14 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 15 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 16 is a magnetic disk control device D shown in FIGS.
Wi operation (step N2, step N7, step N
12 is a flowchart for explaining the details of step N18).

FIG. 17 is a block diagram showing an example of a partial configuration of a conventional computer system.

FIG. 18 is a block diagram showing details of the magnetic disk system shown in FIG. 17;

19 is a flowchart illustrating a data write process of the central processing unit 1 shown in FIG.

20 is a flowchart illustrating a data reading process of the central processing unit 1 shown in FIG.

FIG. 21 is a flowchart illustrating the details of the operation (step S2, step S8) of the magnetic disk controller DCi shown in FIGS. 19 and 20.

22 is a flowchart for explaining details of the operation (step S2, step S8) of the magnetic disk controller DCi shown in FIG. 19 and FIG. 20.

23 is a flowchart for explaining details of the operation (step S2, step S8) of the magnetic disk controller DCi shown in FIGS. 19 and 20. FIG.

24 is a flowchart illustrating the details of the device selection operation (step Sc4) of the magnetic disk device Dik shown in FIG. 21.

FIG. 25 is a flowchart illustrating details of a data write operation (step Sc10) of the magnetic disk device Dik shown in FIG. 22.

FIG. 26 is a flowchart illustrating the details of the data reading operation (step Sc15) of the magnetic disk device Dik shown in FIG. 23.

[Explanation of symbols]

1 central processing unit 2 central processing unit 3 command / data receiving unit 4 response / data transmitting unit 5 data mixing / restoring unit 6 data holding unit 7 storage unit 8 operation unit 9 write data buffer 10 read data buffer 11 control signal generating unit 12, 13 data buffer 14 exclusive OR circuit 15 unit address conversion table 16 central processing unit CA cylinder address signal D primary magnetic disk device d secondary magnetic disk device D11 to D1m, Di1 to Din, Dik, Dj1 to Dj
jp magnetic disk device d11-d1m, di1-din, dik, dj1-d
jp Magnetic disk device DC1 to DCj, DCi, DW1 to DWj, DWi
Magnetic disk controller DK1 to DKj, DKi, DS1 to DSj, DSi
Magnetic disk system EF Positive magnetic disk device F11 to F1m, Fi1 to Fin, Fik, Fj1 to F
jp magnetic disk device G secondary magnetic disk device G11 to G1m, Gi1 to Gin, Gik, Gj1 to Gj
jp Magnetic disk device HA Head address signal RD Read data RG Read command signal ST Status notification signal TC1 Virtual unit address sequence TC2 Subsystem indicator sequence TC3 Real unit address sequence TC4 First primary system real address sequence TC5 Second primary system real address sequence UA unit address signal WD write data WG write command signal

Claims (1)

[Claims] 1. An even number of primary magnetic disk devices for storing information, a secondary magnetic disk device installed at a ratio of one to two primary magnetic disk devices, a command from a central processing unit, and A command / data receiving unit for receiving data, a response / data transmitting unit for transmitting a response and data to the central processing unit, generation of mixed data to be written to the secondary magnetic disk device, and generation of original data from the mixed data. A data mixing / restoring unit for restoring, a data holding unit for temporarily holding write data, and a storage unit for storing a unit address conversion table used for converting a virtual unit address given from the central processing unit into a real unit address. And an operation unit used to update the contents of this unit address conversion table,
A write data buffer for storing data to be written to the primary magnetic disk device or the secondary magnetic disk device, and a read data buffer for storing data read from the primary magnetic disk device or the secondary magnetic disk device,
A control signal generator for generating a unit address signal, a cylinder address signal, a head address signal, a write command signal, and a read command signal for the primary magnetic disk device and the secondary magnetic disk device, and controlling the operation of these components. A magnetic disk system comprising: