JP2927287B1 - Recording and playback device - Google Patents

Abstract

An object of the present invention is to perform an overall operation at high speed without waste when performing data transfer in parallel with a plurality of disk control units and a plurality of drive units. A data recording / reproducing apparatus includes a plurality of drive units (4A-4F) for recording or reproducing data, a plurality of drive control units (1A-1C) for controlling operations of the plurality of drive units (4A-4F) by commands, A status storage unit 3 for storing the operating states of the plurality of drive units for each drive unit. In addition, each drive control unit 1A-
1C, before issuing a command to the drive units 4A to 4F, an operation state confirmation unit 6 for confirming an operation state of each drive unit stored in the status storage unit 3, and an operation state by the operation state confirmation unit 6 Issuance canceling means 8 for canceling the issuance of the command to the drive unit confirmed to have been confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus, and more particularly, to a recording / reproducing apparatus for recording or reproducing data in or from a plurality of drive units.

[0002]

2. Description of the Related Art Hitherto, a recording / reproducing apparatus which uses a plurality of drive units to improve reliability or perform high-speed data transfer has been used. For example, by recording the same data in a plurality of drive units, data loss is prevented even when a failure occurs in one of the drive units. Further, by calculating and recording the exclusive OR of the data, it is possible to restore the data even when a failure occurs in one drive unit. Further, if a plurality of drive control units for controlling the drive units are prepared, even if a failure occurs in one of the drive control units, the processing can be continued in the other drive control unit. Such a system that records and reproduces data by using a plurality of disk units and disk control units is generally called a disk array system, a disk subsystem, or the like.

A conventional data recording / reproducing device employs SCSI as an interface between a drive unit and a host device. Referring to the state transition diagram of FIG.
In I, there are roughly four steps until the drive control unit (initiator) selects the drive unit (target) and executes data transmission / reception. First, check whether the bus is free. In the arbitration phase,
The initiator or target acquires the right to occupy the bus. Next, in the selection or reselection phase, the initiator or target that has acquired the right to occupy the bus selects a target or initiator to be a data transfer partner. This is performed by sending a command for selection to the initiator or target. If the selection is successful, the data is transferred between the initiator and the target.

[0004]

However, in a data recording / reproducing apparatus having a plurality of initiators (drive control units), the other initiator issues a selection command to the drive unit selected by one initiator. There was something to do. Then, the bus is used by an unnecessary command for the drive unit that cannot be selected, and there is a disadvantage that the bus usage rate is reduced. Moreover, when a high-speed process is to be performed as a whole by accessing a plurality of drive units by a plurality of initiators, the process of issuing a selection command to a drive unit that is already operating is actually performed. This is useless processing. That is, since the selection is also performed for the operating drive unit, the bus is occupied during the selection even though the connection is in operation and the connection cannot be established. However, there is a disadvantage that the bus cannot be used.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the prior art, especially when the data transfer is performed in parallel with a plurality of disk controllers and a plurality of drives, and the entire operation is wasted. It is an object of the present invention to provide a data recording / reproducing apparatus which can perform data processing at high speed without any problem.

[0006]

Accordingly, in the present invention, a plurality of drive units for recording or reproducing data, a plurality of drive control units for controlling operations of the plurality of drive units by commands, and a plurality of drive units are provided. And a status storage unit that stores the operation state of each drive unit for each drive unit. The drive control unit checks the operation state of each drive unit stored in the status storage unit before issuing a command to the drive unit. An operation state confirmation unit and an issue suspension unit for suspending the issuance of a command to the drive unit confirmed to be operating by the operation state confirmation unit are provided. This aims to achieve the above-mentioned object.

The operation check means checks the operation state of each drive unit according to the status information (operation state information) stored in the status storage unit without issuing an inquiry to each drive unit. Then, the drive control unit stops issuing the command to the drive unit that is confirmed to be operating by the operation confirmation unit. Therefore, unnecessary commands are not issued to the operating drive unit, and time for waiting for a response is not required.
And the bus is not occupied by unnecessary commands. This solves the above problem.

Further, in the present invention, instead of the operation checking means and the issuance canceling means, status information control means for recording or updating status information in a status storage unit according to the state of the drive unit, and the status information control means Issuing permission / inhibition determining means for determining whether or not to issue a command to the drive unit in accordance with the status information recorded or updated by the control unit.

Here, when transmitting a command to the drive, status information indicating the operation status of the drive unit is written in the status storage unit. Check the operation status of the drive based on the information in the status buffer section, for example,
The command is transmitted when the state is unused.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the present embodiment. As shown in FIG. 1, the data recording / reproducing apparatus includes a plurality of drive units 4A for recording or reproducing data.
To 4F and a plurality of drive control units 1A to 1C for controlling the operations of the plurality of drive units 4A to 4F by commands.
And a status storage unit 3 for storing operating states of the plurality of drive units for each drive unit. The drive units 4A to 4F and the drive control units 1A to 1C are connected by a bus 2. The drive units 4A to 4F are physical storages such as a magnetic disk device and a magneto-optical disk device. The status storage unit 3 stores each drive unit 4
Operation information indicating whether or not A to 4F is operating is stored as status information.

Referring to FIG. 2, each drive control unit 1A
Before issuing a command to the drive units 4A to 4F, the operation state confirmation unit 6 confirms the operation state of each drive unit stored in the status storage unit 3, and operates by the operation state confirmation unit 6. Issuance canceling means 8 for canceling the issuance of a command to the drive unit confirmed as medium
And In the example shown in FIG. 2, the issuance canceling unit 8 cancels the issuance of the command to the operating drive unit, so that the bus 2 is not occupied by an unnecessary command. Therefore, only necessary commands use the bus, and the overall bus use efficiency is improved. This makes the overall operation speed higher.

Referring to FIG. 3, drive control units 1A to 1A
1C is a status information control unit 10 for recording or updating status information in the status storage unit 3 in accordance with the status of the drive units 4A to 4F, and a drive in accordance with the status information recorded or updated by the status information control unit 10. And an issuance determination unit 16 for determining whether to issue a command to the unit.

The status information control means 10 includes, for example,
When a command is issued to a certain drive unit 1A, a first rewrite function 11 for rewriting the corresponding status of the status storage unit 3 to “operating” is provided. Further, the status information control unit 10 sets the operation status of the drive unit 1A to “in operation”, and when the command issued by the drive unit 1A ends, changes the corresponding status in the status storage unit 3 from “in operation” to “standby”. A second rewriting function 12 for rewriting to “medium” is provided.

Further, the status information control means 10
In place of the second rewriting function 12, after the operation state of the drive unit 1A is set to “operating”, when the command issued to the drive unit 1A ends, and when the reconnection with the drive unit 1A succeeds thereafter, A third rewriting function 13 for rewriting the corresponding status in the status storage unit 3 from “in operation” to “standby” may be provided.

When the status stored in the status information storage means 3 is "operating", the status information control means 10 of each of the drive control sections 1A to 1C updates the status to "operating". It is preferable that only the status information control means 10 given the update right to change the status of “operating” to “standby”. This prevents the inconvenience of another drive control unit 1B changing the status of the drive unit that is currently performing data transfer while the drive control unit 1A is operating.

On the other hand, when the issuance determination unit 16 receives an access command from the host device to the drive unit 4A, if the status storage unit 3 records "operating" for the drive unit 4A, the issuance determination unit 16 determines that the drive is in operation. A function is provided for reporting to the upper-level device that it is operating without issuing a command to the unit 4A. This is almost the same function as the issuance canceling means shown in FIG.

As described above, in the present embodiment, the status of the drive unit is managed by the status information, and no command is issued to the operating drive unit, so that the bus use efficiency is improved and, consequently, the entire data recording / reproducing apparatus is improved. Can be processed at high speed.

[0018]

Next, an embodiment of the present invention will be described in detail with reference to FIG. In the example illustrated in FIG. 3, the drive control units 1A to 1C respectively include decoders 23 and 24 that the drive control unit 1 decodes a command output from a higher-level device and outputs to the drive unit 4; Higher-level device controllers 21 and 22 for controlling command transfer are provided.

That is, referring to FIG. 3, the data recording / reproducing apparatus includes a high-order control unit 21 and a high-order control unit 22 for transmitting and receiving commands, a decoding unit 23 and a decoding unit 24 for decoding transmitted commands. Unit 26 and drive unit 27 for executing commands
And a status buffer unit (status storage unit) 25 for storing a status indicating the operation state of the drive unit used.

When operating the drive unit 26 from the upper control unit 21, a command is sent from the upper control unit 21 to the decoding unit 23, and the decoding unit 23 decodes the transmitted command. When the command identified by the decoding unit 23 is a command for controlling the drive unit 26, first, the operation status of the drive 26 is checked in the status register unit 25.

When the drive unit 26 is not operating, the status register unit 25 receives the command and sends the status register unit 25 the status of the operation of the drive unit 26 in response to the command to the drive unit 26 identified by the decode unit 23. The command is recorded, and the transmitted command is executed by the drive unit 26.

The decoding unit 23 monitors the transmitted command until the drive unit 26 completes the command.
Writes the status indicating that the drive unit 29 is not used in the status buffer unit 25 when the operation for the command is completed.

The status register section 25 includes the drive section 2
When the status 6 is the unused status, writing from the decoding unit 23 is permitted. When the decoding unit 23 receives the command, it writes a status indicating the operation of the drive unit 26 for the command. Thereafter, the status buffer unit 25 permits writing of the status of the drive unit 26 from the decoding unit 23, but does not permit writing of the unused decoding unit 24, and makes the status read-only.

After the operation of the drive unit 26 in response to the command is completed, the status that the drive unit 26 is unused is written from the decoding unit 23 to the status buffer unit 25.
At this time, both the decoding unit 23 and the decoding unit 24 permit writing to the status buffer unit 25. When a command is transmitted from the higher-level control unit 21 to the drive unit 26 and the drive unit 26 operates, and a command is transmitted from another higher-level control unit 22 to operate the drive unit 26, the drive unit 26 of the status buffer unit 25 The decoding unit 24 recognizes that the status is “operating”, and stops sending commands to the drive unit 26.

When a command is transmitted from the higher-level control unit 21 to the drive unit 26 and a command is transmitted from another higher-level control unit 22 to operate the drive unit 27 while the drive unit 26 is operating, the drive of the status buffer unit 25 is The decoding unit 24 recognizes that the status of the unit 27 is not used by the drive unit 27, and the status buffer unit 25
Is written that the drive unit 26 is operating, and a command is transmitted from the decode unit 24 to the drive unit 27.

A case where the upper control unit 21 causes the drive unit 26 to perform a read / write operation will be described as an example. The host controller 21 sends a read / write command to the decoder 23. The decoding unit 23 decodes the sent command, and stores the drive 2 in the status register unit 25.
Check the operation status of 6. At this time, the drive unit 26 is in an unused state, and a status indicating this state is recorded in the status buffer unit as a one-byte code.

The decoding unit 23 writes that reading / writing is being performed to the status buffer unit 25 with a one-byte code, and then transmits a write / read command to the drive unit 26. The drive unit 26 receives and executes the read / write command. At this time, drive unit 2
No. 6 includes a seek operation when a read / write command is executed, and a time of about 5 milliseconds may elapse. Therefore, the bus of the drive unit is in a bus-free state, and the other high-order control units It can be used. In this state, the upper control unit 22 performs a read / write operation to the drive unit 26.

Next, the host control unit 22 sends the decoding unit 2
4 and sends a read / write command. The decoding unit 24 decodes the transmitted command, and confirms the operation status of the drive 26 in the status register unit 25. At this time, the drive unit 26 of the status buffer 25
Since the status of “read / write” is written in the status “1”, the decoding unit 24
Returns the selection timeout for 2.

At this time, the decoding unit 24 sends the drive unit 2
Do not use the bus for selection etc. in question 6. Similarly, when performing a read / write operation from the higher-level control unit 22 to the drive unit 27, a read / write command is sent from the higher-level control unit 22 to the decoding unit 24, and the decoding unit 24
Then, the received command is decoded, and the operation status of the drive 26 is confirmed in the status register unit 25. At this time, the drive unit 27 is in the unused state, and the status indicating this state is recorded in the status buffer unit 25.

The decoding unit 23 writes to the status buffer unit 25 that reading / writing is in progress,
Thereafter, a write / read command is transmitted to the drive unit 26. The drive unit 27 receives and executes the read / write command. When the processing of the read / write command of the drive unit 26 is completed, if the bus is in the bus free state, the drive unit 26 reconnects to the decoder unit 23.

After reconnecting and confirming that the read / write command operation has been completed, a status indicating that the drive unit 26 is in an unused state is written from the decoding unit 23 to the status buffer unit 25, and is written to the upper control unit 21. Returns command operation completion.

As described above, according to the present embodiment, when transmitting a command to the drive, the status indicating the operation status of the drive unit is written in the status buffer unit, so that the processing speed of the magnetic disk device itself can be improved. I can measure. This is because the operation state of the drive is confirmed based on the information in the status buffer unit, and a command is transmitted when the state is unused, so that the bus utilization is reduced.

[0033]

Since the present invention is constructed and functions as described above, according to this, the operation check means stores the operation state of each drive unit in the status storage unit without issuing an inquiry to each drive unit. The drive control unit checks according to the status information (operating state information)
For the drive unit that is confirmed to be operating by the operation check unit, the command issuance is stopped, so that unnecessary commands are not issued to the operating drive unit.
Therefore, the bus is not occupied by unnecessary commands, thereby improving the efficiency of use of the bus, thereby increasing the overall processing speed, and issuing unnecessary commands and responding to them. Therefore, this also provides an unprecedented superior data recording / reproducing apparatus capable of performing higher-speed data transfer.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a detailed configuration of a drive control unit shown in FIG.

FIG. 3 is a block diagram illustrating another example of the drive control unit illustrated in FIG. 1;

FIG. 4 is a block diagram showing a configuration of one embodiment of the present invention.

FIG. 5 is a state transition diagram showing SCSI state transition.

[Explanation of symbols]

1A to 1C Drive control unit (for example, array controller) 2 Bus 3 Status storage unit 4A to 4F Drive unit (for example, magnetic disk device) 6 Operation status check unit 8 Issuance stop unit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 3/06 540 G11B 19/02 501

Claims (8)

(57) [Claims] 1. A plurality of drive units for recording or reproducing data, a plurality of drive control units for controlling operations of the plurality of drive units by commands, and an operation state of the plurality of drive units for each drive unit A status storage unit for storing, the drive control unit, before issuing a command to the drive unit, an operation state confirmation unit that confirms the operation state of each drive unit stored in the status storage unit,
A recording / reproducing apparatus, comprising: an issue suspending means for suspending the issuance of a command to the drive unit which is confirmed to be operating by the operating state confirming means. 2. A plurality of drive units for recording or reproducing data, a plurality of drive control units for controlling operations of the plurality of drive units by commands, and an operation state of the plurality of drive units for each drive unit A status storage unit that stores the status information, wherein the drive control unit records or updates status information in the status storage unit according to the state of the drive unit, and the status information control unit records or updates the status information. Recording / reproducing apparatus comprising: issuance permission / inhibition determining means for determining whether or not to issue a command to the drive unit in accordance with the received status information. 3. The status information control means has a first rewriting function of rewriting a corresponding status of the status storage unit to “operating” when a command is issued to the drive unit. The recording / reproducing apparatus according to claim 2. 4. The status information control means sets the corresponding status of the status storage unit to "operating" when the command issued to the drive unit ends after setting the operation state of the drive unit to operating. From "waiting"
4. The recording / reproducing apparatus according to claim 3, further comprising a second rewriting function for rewriting the data. 5. The status information control means, when the operation state of the drive unit is set to “operating”, when a command issued to the drive unit ends, and when reconnection with the drive unit succeeds thereafter, The recording / reproducing apparatus according to claim 4, further comprising a third rewriting function for rewriting a corresponding status in the status storage unit from "operating" to "waiting". 6. The status information control unit of each of the drive control units, when the status stored in the status information storage unit is “operating”, the status information control unit updates the status information to “operating”. 6. The recording / reproducing apparatus according to claim 2, wherein an update right for changing the status of "operating" to "waiting" is given only to the means. 7. The issuance determination unit determines whether the drive unit is “operating” when the status storage unit records “in operation” when an access command from the host device to the drive unit is issued. 6. The recording / reproducing apparatus according to claim 2, further comprising a function of reporting to the host apparatus that the operation is in progress without issuing a command. 8. The recording / reproducing apparatus according to claim 1, wherein the drive control unit is a decoder that decodes a command output from a host device and outputs the command to the drive unit.