JPH06309110A - Composite memory device - Google Patents

Abstract

PURPOSE:To obtain a composite memory device large in capacity and provided with exchangeability and high speed performance by extending data on a medium inserted newly by a data control part when the medium of a first memory device is exchanged, and transferring it to a second memory device. CONSTITUTION:The memory capacity of a hard disk 16 is set at, for example, capacity of two times that of one plane of an optical disk 18, and also, the block size of it at the one of two times. All the write data in a computer 10 to be transferred to the composite memory device 12 pass a data control part 14, and are tranferred to the hard disk 16 once. When the data is transferred from the computer 10 to the hard disk 16, no data compression is performed, and the data is directly written on the hard disk 16. The data written on the hard disk 16 in such way is transferred from the hard disk 16 to the optical disk 18 in a time while no start-up from the computer 10 to the composite memory device 12 is applied i.e., as background processing. At this time, the compression and switching processing of the data are performed at the data control part 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device of a computer system, and more particularly to a composite type storage device which has a large capacity and is exchangeable and high-speed.

[0002]

2. Description of the Related Art A storage device is one of the most basic devices of a computer system, and it is desirable that it has a large storage capacity and a fast access time. Moreover, it is better if it is cheap and movable, but there is no one having all the properties, and conventionally, a storage device having each property is used in combination according to the purpose of use. Recently, optical disks have been in the spotlight due to their large capacity and replaceability.

Further, conventionally, data has been compressed to reduce the data communication time.

An example of compression by run length is shown in FIG. When the data to be compressed is an exchange pattern of '1' or '0' or a data pattern close to it, the amount of information may increase slightly like the first byte (Byte) of the compressed data in FIG. When "1" and "0" are consecutive, the amount of information after compression can be greatly reduced. Data is recorded in the storage device in block units such as 512 Byte and 1024 Byte, but "1" and "0" are often filled in areas other than valid data at the beginning of the block, and thus data compression as described above is not possible. Great effect.

[0005]

However, since data compression is performed by temporarily storing the data in a temporary memory and then applying the data later, the data compression requires operator intervention and processing time for the compression. There was a problem of needing. For this reason, compression has not been performed steadily, but has generally been performed as additional processing.

Further, with respect to an optical disc, since it is not possible to overwrite, the recording / reproducing head is heavy, and the eccentricity of the disc is large, it takes a long positioning time, the output of the recording laser is limited, and the frequency characteristic of the recording / reproducing head is limited. Therefore, there is a problem that the speed is generally several to ten times lower than that of a widely used hard disk because the rotation speed of the disk cannot be sufficiently increased.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a composite type storage device having a large capacity and having exchangeability and high speed.

[0008]

According to the present invention, there is provided a composite storage device in which a plurality of storage devices are combined with a storage device of a computer system, and a first storage device capable of medium exchange and data from a computer. Data compression between a high-speed second storage device, which has a storage capacity larger than that of the first storage device, in which writing and data reading are performed, and the first storage device and the second storage device. A data control unit that performs decompression, replacement processing, and cache control, and compresses the data written from the computer to the second storage device by the data control unit while the computer is not accessing the data. , Transferred to the first storage device, and when the medium of the first storage device is exchanged, the data on the newly inserted medium is expanded by the data control unit to the second storage device. To transfer Accordingly, the storage capacity of the first storage device, so as to expand the storage capacity of the second storage device, in which to achieve the above object.

[0009]

According to the present invention, the first storage device capable of exchanging media, the second storage device having a larger capacity and accessed by a computer, and the data control unit for performing data compression / expansion are provided. A composite storage device is configured.

When there is an access from the computer, for example, at the time of writing, the write data passes through the data control unit, is not subjected to data compression, and is once written to the second storage device. Then, as a background process, the written data is passed from the second storage device through the data control unit and data compression is performed during the time period when the computer does not start up the composite storage device. Is transferred to the storage device. For this reason, the composite storage device appears to the computer as a storage device having a larger capacity than it actually is. or,
When the medium of the first storage device is replaced and a new medium is inserted, the compressed data in the medium is read by the data control unit, decompressed, and transferred to the second storage device.

When all the transfers are completed, all accesses from the computer are made to the second storage device, and as a result, high-speed processing that cannot be realized by the first storage device becomes possible. And after that, regardless of whether there is access,
The process of compressing the data in the second storage device through the data control unit during the background and transferring it to the first storage device is repeated.

[0012]

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

FIG. 2 is a block diagram showing a schematic configuration of this embodiment.

In FIG. 2, 10 is a computer, 12 is a composite storage device of the present invention, 14 is a data control unit, 16 is a high-speed storage device, for example, a hard disk, 18 is a medium exchangeable (removable) storage device. , An optical disc, for example. Here, for example, the storage capacity of the hard disk 16 is twice the single-sided capacity of the optical disk 18, and the block size of the hard disk 16 is twice the block size of the optical disk 18.

Next, the basic operation of this embodiment will be described.

All write data transferred from the computer 10 to the composite type storage device 12 is once transferred to the hard disk 16 through the data control unit 14. When data is transferred from the computer 10 to the hard disk 16, the data is not compressed but is directly written to the hard disk 16. The data written in the hard disk 16 is transferred from the hard disk 16 to the optical disk 18 as a background process when the computer 10 does not start up the composite storage device 12. At that time, the data control unit 14 performs data compression and replacement processing described later.

The internal configuration of the data control unit 14 is, for example,
As shown in FIG. 2, the computer 10 and the composite storage device 12
Interface circuit 20 with the hard disk 16 or the optical disk 18, the CPU 24 of the data control unit 14, the ROM 26 storing the operation program of the CPU 24, the work RAM 2 of the CPU 24.
8, a compression / expansion circuit 30, a compression / expansion RAM 32, and a data buffer RAM 34 of the data control unit 14. The data buffer RAM 34 is of non-volatile type because the replacement management information described later is also stored therein.
Although the compression / expansion can be performed by the CPU 24, data control is performed so that the optical disc 18 can be quickly taken out and recording / reproduction can be performed at the same high speed as the hard disc 16 when the optical disc 18 is inserted. The section 14 is provided with a dedicated circuit 30 for compression / expansion.

Next, as an example of the operation of the data control unit 14, the block size of the hard disk 16 is 1024B.
yte (hereinafter, simply referred to as B) and a case where the block size of the optical disk 18 is 512B will be described.

The data sent from the computer 10 to the hard disk 16 is compressed by the data control unit 14 to 5
12B or less, optical disc 1 in the background
8 is transferred.

As a result, from the computer 10, the composite type storage device 12 is twice as large as the optical disc 18 (= 1024B / 51).
It is regarded as a storage device having a storage capacity of 2B).
That is, when the one-sided capacity of the optical disc 18 is 300 MB,
From the computer 10, it is seen as a storage capacity of (600 MB-α) (α will be described later).

Depending on the data, the compression rate may be twice or less, so the optical disc 18 is provided with a spare area and a spare management information area. An example of the operation of the replacement process is shown in FIGS. 3 shows the address space of the hard disk 16 and FIG. 4 shows the address space of the optical disk 18,
3 corresponds to before data compression, and FIG. 4 corresponds to after data compression.

Addresses of the user data area of the hard disk 16 and the user data area of the optical disk 18 (#
, 1, ..., # N + 1, ...) Corresponds to one to one. The address specified by the computer 10 indicates the address of the user data area, and the replacement area and the replacement management information area cannot be recognized by the computer 10.

FIGS. 3 and 4 show an example in which 1024B of # 1 is compressed to 201B and # 2 is compressed to 199B. The block size of the optical disk 18 after compression is 5
If it is 12B or less, no special processing is required, but FIG.
In the case of exceeding 512B after compression as in the example of # 3, the data exceeding 512B is allocated to the spare area # 3.

Correspondence information between the user area and the replacement area is stored in the memory 34 of the data control unit 14, but a replacement management information area is also provided on the optical disk 18 in preparation for replacement of the optical disk 18. The data in the user area and the replacement area are compressed, but the data in the replacement management information area is not compressed. In order to reproduce the data at high speed, the replacement management information on the memory 34 and the optical disk 18 is rearranged in ascending or descending order of address each time a new replacement process is performed at the time of recording. Note that α described above is the total capacity of the replacement area and the replacement management information area. Unloading of the optical disc 18 is possible after all the replacement management information is transferred from the memory 34 onto the optical disc 18. In preparation for a power failure before all the replacement management information is transferred onto the optical disc 18, the memory 34 in which the replacement management information is stored is of a non-volatile type that does not lose its contents even when the power is turned off.

Next, the processing when the optical disk 18 is loaded will be described. Immediately after loading, the replacement management information on the optical disc 18 is transferred to the memory 34 of the data control unit 14. User data is read from the optical disc 18 in the address order to the data control unit 14, expanded every 512B, and transferred to the hard disk 16 in block units of 1024B. When the replacement management information already stored in the memory 34 includes the address of the block to be transferred next, the data of 512B read from the user data area and the replacement area indicated by the replacement management information. The 512B data read from the hard disk 1 is decompressed and the combined data is 1024B data and is stored in the hard disk 1.
6 is transferred. The above processing is performed until the data on all the optical disks 18 are transferred to the hard disk 16, and when all the transfer is completed, all accesses from the computer 10 are made to the hard disk 16, and as a result,
High-speed processing that cannot be realized by the optical disk 18 becomes possible.

From then on, regardless of whether or not there is access from the computer 10, the hard disk 16 is in the background.
The compression is performed in the ascending order of the addresses, and the process of transferring the compressed data to the optical disc 18 is repeated.

Next, from the optical disk 18 to the hard disk 1
A case will be described in which an access is made from the computer 10 to the device 12 before the transfer of all the data to 6 is completed. FIG. 5 shows an address map in that case. The area A of the user data area indicates an area where the data has already been decompressed and transferred to the hard disk 16, and the area B indicates an area which has not been transferred yet.

When writing or reading is designated in the area A, data is transferred between the hard disk 16 and the computer 10.

When reading is specified in the B area, it is checked from the replacement management information on the memory 34 of the data control unit 14 whether replacement processing has occurred. If replacement processing has not occurred, the data in the B area is checked. Is expanded and transferred to the computer 10. If the replacement process has occurred, the data in the user data area and the data in the replacement area are expanded and the computer 10
Transferred to.

When the writing is designated in the B area and the replacement processing does not occur, the writing is directly performed in the B area.
If the designated area has been previously replaced, the replacement management information in the memory 34 is invalidated.

If writing is designated in the B area and replacement processing occurs, B up to 512 B of data is written.
Record in the area. If the area designated for writing has been previously replaced, the replacement management information on the memory 34 is updated, and data exceeding 512 B is overwritten on the replacement area on the optical disc 18. If the specified area has not been previously replaced, memory 3
4 replacement management information has been updated, and the hard disk 1 has already been updated.
5 in area A of the replacement area that has been transferred to 6 and is no longer valid
Record data over 12B.

[0032]

As described above, according to the present invention, when the storage device is not activated by the computer, the compression / decompression process is automatically performed on the storage device side as a background process. Can be used for compression / expansion processing without disturbing access from the computer or requiring operator intervention, and realizes a large-capacity storage device that has both the replaceability of optical disks and the high speed of hard disks. be able to.

[Brief description of drawings]

FIG. 1 is a bit configuration diagram showing an example of data compression.

FIG. 2 is a block diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 3 is an address map of the hard disk of this embodiment.

FIG. 4 is likewise an address map of the optical disk showing the replacement processing operation.

[FIG. 5] Similarly, an address map of an optical disc during data transfer

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Computer 12 ... Composite storage device 14 ... Data control unit 16 ... High-speed storage device (hard disk) 18 ... Medium exchangeable storage device (optical disk) 30 ... Compression / expansion circuit

Claims (1)

[Claims] 1. A composite type storage device using a combination of a plurality of storage devices as a storage device of a computer system, wherein a medium exchangeable first storage device and data writing and data reading from a computer are performed. A high-speed second storage device having a storage capacity larger than that of the first storage device, and data compression / expansion, replacement processing, and cache control between the first storage device and the second storage device. And a data control unit for performing the above, and while the computer does not access, the data written from the computer to the second storage device is compressed by the data control unit and stored in the first storage device. By transferring, when the medium of the first storage device is exchanged, the data on the newly inserted medium is expanded by the data control unit and transferred to the second storage device. Note of The storage capacity of the device, the composite memory device characterized by expanding the storage capacity of the second storage device.