JP2684803B2 - Information recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording / reproducing data on / from an exchangeable information recording medium, and more particularly to an information recording / reproducing apparatus for accelerating data access by using a cache. It is a thing.

2. Description of the Related Art A conventional information recording / reproducing apparatus is disclosed in Nikkei Electronics 1985.3.11, pp.159-187.

FIG. 2 is a block diagram of this conventional information recording / reproducing apparatus, in which reference numeral 1 is a host computer CPU as a host apparatus for recording / reproducing data on / from the disk device 12.
Reference numeral 2 is a main memory of the CPU 1 which stores data and programs. Reference numeral 3 is a channel of the CPU 1 which controls input / output of data. A disk controller 10 controls the disk device 12 and the disk cache 11 to speed up data recording and reproduction. 11 is a disk cache, a disk device
This is a memory for speeding up data access between the CPU 12 and the CPU 1.

The operation of the conventional information recording / reproducing apparatus configured as described above will be described with reference to the operation diagram shown in FIG.

(1) In the case of data reading When a certain data is accessed from a specific file, the disk controller 10 prefetches (prefetches) from the disk device 12 at the same time if the next block of the file is not in the disk cache 11. Keep it.

In this state, if the CPU 1 issues a data read request 100 for a certain file, the disk controller 10
Refers to the disk cache directory DIR stored in the disk controller 10 and checks whether the target data block of the file is in the disk cache 11. When there is data (hit) in the disk cache 11, the data block is transferred from the disk cache 11 to the main memory 2 via the channel 3. In the case of a disk cache miss, several blocks (consisting of sectors) including the target block are read from the disk device 12 to the disk cache 11, and the target block therein is transferred to the main memory 2. Therefore, if the disk cache 11 hits with a high probability, the data starts to be transferred from the disk cache 11 at a very high speed, and the data access speed can be improved.

(2) When writing data In this case, the disk cache 11 and the disk device 12
Write through (Write-th
Two well-known methods, a rough method and a write-back method, are used.

In the write-through method, the data is first transferred to the disk device 12
And write to the disk 13 (101 in FIG. 3).
(Data flow indicated by), if there is a block corresponding to the recorded data in the disk cache 11 and there is a hit,
Invalidate the corresponding block of disk cache 11 or
Alternatively, the same data is written in the disk cache 11 (flow shown in FIG. 103).

On the other hand, in the write-back method, the writing of data to the disk cache 11 is prioritized (the flow shown in FIG. 104), and the data replacement mechanism of the disk cache 11 needs an empty area to put new data in the disk cache 11. When it is determined that the contents of the disk cache 11 and the contents of the disk device 12 should match when the data becomes unnecessary, the data of the disk cache 11 is transferred to the disk device 12 and the data is transferred to the disk device 12. Write to 13. (Flow shown in FIG. 105) Problems to be Solved by the Invention However, in the above-described write-back method,
If the disk 13 is replaced before the data in the disk cache 11 is recorded in the disk device 12, the data will not be recorded correctly in the disk 13.

On the other hand, in the write-through method, unlike the write-back method, data is not lost due to the disk exchange, but the disk controller 10 records the data in the disk device 12 each time it receives a data write command from the CPU 1, so the data write operation is performed. There was a problem that it took time.

In view of the above point, the present invention makes it possible, when exchanging an information recording medium, to regulate the exchange of the information recording medium to correctly record data on the information recording medium, and to perform high-speed data access to the data recording section. An object is to provide an information recording / reproducing device.

Means for Solving the Problems In order to achieve the above object, the present invention provides a disk device that records and reproduces data on an exchangeable disk-shaped information recording medium, a disk cache that temporarily stores the data, and A disk controller and a disk controller for controlling a data recording / reproducing operation with respect to the disk cache, wherein the disk controller can take out the disk device from the information recording medium based on a command from a host device. Alternatively, a disc exchange control means for making the disc unremovable state, a disc lock state storage means for storing the removability state of the information recording medium in the disc exchange control means, and a data write command from the host device , Recording data transferred from the host device to the disc Write-through recording means for transferring the data to a device and recording it on the information recording medium, writing the recording data in the disk cache in the same manner, and notifying the host device of the end of execution of the data write command; Upon receiving the data write command, cache recording means for recording the record data only in the disk cache and then notifying the end of execution of the data write command, and transferring the data in the disk cache to the disk device, The information recording / reproducing apparatus is provided with a write-back recording unit for recording on an information recording medium.

The information recording / reproducing apparatus of the present invention has the above-mentioned configuration, and when the disk control device receives a data write command from the host device, the disk lock state saving means saves the state in which the information recording medium can be taken out from the disk device. While recording, the recording data transferred from the higher-level device is transferred to the disk device and recorded on the information recording medium, and the recording data is also written to the disk cache in the same way, and then the execution of the data write command is terminated. Notify the host device. Similarly, when the disk control device receives a data write command from the host device and the disk lock status saving means saves a state that cannot be taken out, the data write command is written only after the recorded data is recorded in the disk cache. Is notified to the higher-level device, and then the data in the disk cache is transferred to the disk device and recorded on the information recording medium.

Example An information recording / reproducing apparatus according to an example of the present invention will be described below.
This will be described with reference to the drawings.

FIG. 1 shows a block diagram of an information recording / reproducing apparatus in an embodiment of the present invention. In FIG. 1, numbers 1, 2,
Reference numeral 3 denotes the same block as the same number in FIG. 2, 4 is a disk control device for controlling the disk device 6 and the disk cache 5 to speed up data recording and reproduction, and 5 is a disk device 6 from the CPU 1 to the CPU 1. A disk cache in which data is read out and stored in advance in order to speed up data access, 6 is a disk device in which a disk 9 can be replaced, and 7 is a disk device 6 based on a command from a host device.
The lock processing unit 8 determines whether or not the disc 9 can be taken out from the disc, and determines whether or not the disc 9 can be taken out. The lock state storage register 9 is a disc which is an information recording medium for recording or reproducing data.

The data writing operation of the information recording / reproducing apparatus of the present embodiment having the above-described configuration will be described below. The data read operation is omitted because it can be performed in the same manner as the conventional example.

First, a series of operations when the disk controller 4 sets the disk 9 in a state where the disk 9 cannot be taken out based on a command from the CPU 1 and a data writing operation when the disk 9 cannot be taken out from the disk device 6 will be described.

The CPU 1 sends a command to the disk controller 4 to put the disk 9 in a state in which it cannot be taken out from the disk device 6. The lock processing unit 7 makes the disk 9 not removable from the disk device 6 and stores in the lock status storage register 8 that the disk 9 is not removable.

Next, regarding the write operation, the CPU 1 issues a data write command to the disk controller 4 and transfers the data from the main memory 2. When the lock processing unit 7 refers to the lock state saving register 8 and determines that the disk 9 cannot be taken out from the disk device 6, the disk control device 4 transfers the data transferred from the main memory 2 via the channel 3. Write to the disk cache 5 and notify the CPU 1 of the end of execution of the data write command. Disk controller 4
Is the contents of the disk cache 5 and the contents of the disk device 6 when the data replacement mechanism of the disk cache 5 needs an empty area to newly store data in the disk cache 5, or when the data becomes unnecessary. When it is determined that the contents should match, the data in the disk cache 5 is transferred to the disk device 6 and written back to the disk 9. (So-called write-back writing is performed.) Next, a series of operations for changing the state in which the disc 9 cannot be taken out from the disc device 6 to the state in which it can be taken out will be described. When the disk controller 4 receives a command from the CPU 1 to put the disk 9 in a state in which it can be taken out from the disk device 6, first, the unrecorded data in the disk cache 5 and transferred to the disk device 6 is transferred to the disk device 6. Write in. After that, the lock processing unit 7 saves in the lock state saving register 8 that the disk 9 is in a removable state, and also makes the disk 9 ready for removal from the disk device 6.

That is, when the disk 9 cannot be taken out, the number of actual data recordings from the disk cache 5 to the disk 9 in the disk device 6 can be greatly reduced by appropriately selecting the capacity of the disk cache 5 and the data replacement algorithm. The writing operation can be performed at high speed. Needless to say, this effect becomes extremely large if, for example, the directory portion having the highest rewriting frequency is made resident in the disk cache 5.

Next, the data writing operation when the information recording / reproducing apparatus is turned on, or when the disk control device 4 is in a state where the disk 9 can be taken out from the disk device 6 based on a command from the CPU 1 will be described. Here, it is assumed that the lock state storage register 8 is set so that the disc 9 can be taken out when the information recording / reproducing apparatus is powered on.

The CPU 1 issues a data write command to the disk controller 4 and transfers data from the main memory 2. Lock processing unit 7
However, if the disk controller 4 refers to the lock state saving register 8 and determines that the disk 9 is in a state where it can be taken out from the disk device 6, the disk controller 4 transfers the data transferred from the main memory 2 via the channel 3 to the disk device 6. Then, the data is recorded on the disk 9 and also recorded on the disk cache 5, and then the CPU 1 is notified of the end of execution of the data write command. (So-called write-through writing is performed.) That is, when the disk 9 can be taken out, the data is immediately transferred to the disk device 6 and the disk 9 is surely transferred.
To record.

As described above, according to the information recording / reproducing apparatus of the embodiment of the present invention, when the data access is speeded up by using the disk cache, the exchange of the disk is prohibited so that the cache effect is reduced even at the time of writing. It is possible to prevent uncertain writing of data due to disk exchange.

As described above, according to the present invention, when the information recording medium cannot be taken out, when the information recording medium can be taken out by using the cache, the data writing to the information recording medium can be greatly reduced to speed up. The data can be recorded on the information recording medium immediately and can be surely recorded, and the reliability of the disk is greatly improved, so that its practical effect is great.

[Brief description of the drawings]

FIG. 1 is a block diagram of an information recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram of a conventional information recording / reproducing apparatus, and FIG.
The figure is an explanatory diagram of the data writing operation of the conventional example. 1 ... Host computer CPU, 2 ... Main memory, 3 ...
Channel, 4 ... Disk control device, 5 ... Disk cache, 6 ... Disk device, 7 ... Lock processing unit,
8 ... Lock state saving register, 9 ... disk.

Front page continuation (72) Inventor Yuji Takagi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hiroshi Hamazaka 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. ) References JP-A-61-28124 (JP, A) JP-A-62-242253 (JP, A) JP-A-64-36351 (JP, A) Actual development Sho-63-5539 (JP, U) Nikkei Computer, [13] (1982-3-22) pp. 71-85 “Seeing the function of disk cache that fills the access gap” Nikkei Electronics, [350] (1984-8-27) pp249-273 “Exploring cache methods that increase the transfer rate of magnetic disks by 5 to 15 times” "

Claims (8)

(57) [Claims] 1. A disk controller for controlling a data recording / reproducing operation for a disk device for recording / reproducing data on / from an exchangeable information recording medium and a disk cache for temporarily storing the data, wherein the disk device comprises: A disk exchange control means for bringing the information recording medium into a removable state or a non-removable state;
A disk lock state saving means for saving the removal possibility of the information recording medium in the disk exchange control means, and recording data transferred from a higher-level device to the disk device for recording on the information recording medium, Similarly, write-through recording means for writing the recording data in the disk cache, cache recording means for recording the recording data only in the disk cache, and data in the disk cache for transferring to the disk device Write-back recording means for recording on a recording medium, and when the disk lock state saving means saves a state in which the information recording medium can be taken out from the disk device, the write-through recording means is used. The lock state storage means removes the information recording medium. The while saving a state which does not, the disk controller, characterized by first using then the write-back printing unit using said cache storage means. 2. A disk device for recording / reproducing data on / from an exchangeable information recording medium, a disk cache for temporarily storing the data, and a disk control for controlling a data recording / reproducing operation for the disk device and the disk cache. And a disk control device,
A disc exchange control means for putting the disc device into a state in which the information recording medium can be taken out or a state in which the information recording medium cannot be taken out based on a command from a host device; and a disc replacement control means for taking out the information recording medium. When receiving a data write command from the host device and a disk lock state storage means for storing the permission / prohibition state, the recording data transferred from the host device is transferred to the disk device and recorded on the information recording medium, and Similarly, after writing the recording data to the disk cache, write-through recording means for notifying the host device of the end of execution of the data writing command; and when receiving the data writing command, the recording data is transferred to the disk cache. Execution of the data write command after recording only in And a write-back recording means for transferring the data in the disk cache to the disk device and recording the data in the information recording medium. The disk control device stores the disk lock state. When the means stores the state in which the information recording medium can be taken out from the disk device, the write-through recording means is used, and the state in which the disk lock state storing means cannot take out the information recording medium is stored. Is an information recording / reproducing apparatus characterized in that the cache recording means is used first, and then the write-back recording means is used. 3. A disk control device receives a command from a host device to put the information recording medium into a removable state when the disk lock state storage means stores the information recording medium in a non-removable state. First, the write-back recording means is used to record unrecorded data in the information recording medium in the disk cache on the information recording medium, and thereafter the information recording medium is taken out using the disk exchange control means. The information recording / reproducing apparatus according to claim 2, wherein the information recording / reproducing apparatus is set in a ready state. 4. The write-back recording means, when the disk lock state saving means saves the information recording medium in a state in which it cannot be taken out, wants to match the contents of the disk cache with the contents of the information recording medium. 4. The information recording / reproducing apparatus according to claim 2, wherein when the determination is made, unrecorded data is recorded on the information recording medium in the disc cache and on the information recording medium. 5. The write-back recording means requires an empty area to newly store data in the disk cache when the disk lock state saving means saves the information recording medium in a state in which it cannot be taken out. sometimes,
The information recording / reproducing apparatus according to claim 2, 3 or 4, wherein unrecorded data is recorded on the information recording medium in the disc cache and on the information recording medium. 6. The write-back recording means, when the disk lock state saving means saves the information recording medium in an unremovable state and when the data in the disk cache becomes unnecessary, the disk cache 5. The information recording / reproducing apparatus according to claim 2, 3 or 4, wherein unrecorded data is recorded in the information recording medium in the information recording medium. 7. A disk control method for controlling a data recording / reproducing operation for a disk device for recording / reproducing data on / from an exchangeable information recording medium and a disk cache for temporarily storing the data. When the information recording medium can be taken out or cannot be taken out and the information recording medium can be taken out from the disk device, the recording data is transferred to the disk device and the information recording medium is transferred. When the information recording medium is in a state where the information recording medium cannot be taken out, the recording data is preceded by recording the recording data only in the disk cache, and then recording the recording data in the disk cache. Data stored in the disk cache is transferred to the disk device to record the information. Disk control method and recording on the medium. 8. When changing an information recording medium from a non-removable state to a removable state, first, unrecorded data in the information recording medium in the disk cache is recorded on the information recording medium, and thereafter, 8. The disk control method according to claim 7, wherein the information recording medium is set in a removable state.