JPH0955071A - Auto-changer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for accessing the data on a medium. SOLUTION: This device is provided with plural recording media 2, and records or reproduces information on the recording media 2 based on an instruction of a host computer 7, and when viewing from the host computer 7, it controls plural recording media 2 as one recording medium logically. At this time, a cache memory 9 for storing the data of the recording media 2 is provided, and when one file data are ranged to and recorded on plural recording media 2, the whole or its part of the file data ranging to plural recording media 2 are stored preferentially in the cache memory 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic changer device for accommodating a plurality of recording media to record information or reproduce recorded information.

[0002]

2. Description of the Related Art The following two types of conventional autochanger devices are known. That is, the first type is a type in which a plurality of recording media are treated as independent recording media, and the recording media are manually replaced by a replacement mechanism. In such an apparatus, when the recording medium is replaced, the recording medium used so far is ejected, and the host computer is notified that the new recording medium is to be used. At that time, the host computer automatically performs a logical process associated with the exchange of the recording medium by taking in the information recorded in the recording medium. Therefore, in this case, since each recording medium is logically independent one by one, the information necessary for the host computer to process is recorded in each recording medium.

Next, the other is that the autochanger device itself becomes one storage device, and when viewed from the host computer, the plurality of recording media appear as only one recording medium, and a mere large capacity storage is required. It is a type that behaves like a device. In such an apparatus, since a plurality of recording media are managed as one recording medium, the file management information and file management method therein are different from those of the previous type. That is, in this type of autochanger device, in many cases, all information of the recording medium in the autochanger device is stored in a separately prepared hard disk (fixed disk) or memory on the host computer side. In that case, when the power is turned on or immediately after a reset, all the recording media in the autochanger device are scanned to collect various information, and the management information is reconstructed in order to manage it as one recording medium. It is stored on the hard disk or the host computer. There are also caches of accessed data in a host computer or an external hard disk. By doing so, when the data is updated, the relevant recording medium can be updated immediately without loading the relevant recording medium and performing the update process. This makes it possible to compensate for the time loss due to the exchange time of the recording medium.

[0004]

However, in the above-described conventional autochanger device, particularly in the case of managing a plurality of recording media as one recording medium as described above, when the data capacity of the data file is large, one data file May be recorded across two or more recording media. In such a case, for example, if one data file is recorded across two recording media, to access that data file,
First, the recording medium on which the first half of the data file is recorded must be loaded. Then, after that, it is necessary to load the recording medium in which the data of the latter half is recorded.
It takes twice the processing time to read one data file. As described above, conventionally, when one data file is recorded across a plurality of recording media, there is a problem that it takes time to access the data.

In view of the above-mentioned conventional problems, the present invention shortens the time required to load a recording medium by preferentially storing data recorded on a plurality of recording media in a cache memory. It is an object of the present invention to provide an autochanger device capable of

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to have a plurality of information recording media, record information on the recording media or reproduce the recorded information based on an instruction from a host computer, and the host. When viewed from a computer, in an autochanger device that logically manages the plurality of recording media as one recording medium, a cache memory for storing data of the recording medium is provided, and one file data includes a plurality of recording media. When the data is recorded over the plurality of recording media, all or a part of the file data over the plurality of recording media is preferentially stored in the cache memory.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of an information recording / reproducing system including an autochanger device of the present invention. In FIG. 1, reference numeral 1 is an autochanger device, in which a plurality of recording media 2 are stored in a medium storage portion. Further, in the autochanger device 1, a drive (information recording / reproducing device) for recording / reproducing information on / from the recording medium 2 (information recording / reproducing device), a recording medium 2 in a medium accommodating portion is transferred to the drive and exchanged (not shown) A controller 3 for controlling the mechanism, the drive, the exchange mechanism, and the like are provided. Controller 3 is C
It comprises a PU 4, a ROM 5 in which a control program is stored, and a RAM 6 for storing a plug to be described later.

The autochanger 1 is connected to a host computer 7 which is a host controller via a SCSI interface 8 and records and reproduces information based on instructions from the host computer 7. In this case, the autochanger device 1 is one large-capacity storage device as described above, and when viewed from the host computer 7, the plurality of recording media 2 are logically treated as one recording medium. Also,
An external storage device (hard disk) 9 is connected to the autochanger device 1 through a dedicated interface. The hard disk 9 is used as a cache memory for storing the data of the recording medium 2 as described later in detail.

Next, the host computer 7 of the above embodiment
The operation when the data read command is received from FIG. 2 will be described with reference to FIG. First, when the autochanger device 1 receives a command from the host computer 7, the autochanger device 1 analyzes the request command from the host computer 7 and determines whether the command is an access that spans a plurality of recording media 2 (step 1). ). That is, it is judged whether or not the file data has a large capacity and the file data recorded on two or more recording media 2 is accessed. Here, if the access is over a plurality of recording media 2, the autochanger device 1 loads the corresponding plurality of recording media. For example, the data file requested by the host computer 7 is recorded over two recording media, and the data in the first half of the data file is recorded on the recording medium 2a.
If the latter half of the data file is recorded on the recording medium 2b, the autochanger device 1 first loads the recording medium 2a on which the first half of the data is recorded. (Step 2).

That is, the controller 3 of the autochanger device 1 controls the medium exchange mechanism (not shown) to set the corresponding recording medium 2a in the drive. Next, the controller 3 controls the drive to control the recording medium 2a.
The process of reading the first half of the corresponding file data is performed (step 3). The controller 3 transfers the read data to the host computer 7 and stores it in the cache memory (step 3). When the reading of the data of the first half is completed, the controller 3 loads the recording medium 2b in which the data of the second half of the file data is recorded (step 4), and performs the process of reading the data of the latter half (step 5). . The latter half data is also transferred to the host computer 7 under the control of the controller 3 and stored in the cache memory (step 5).

Here, the hard disk 9 is used as the cache memory as described above, and the file data recorded over a plurality of recording media is preferentially stored in the cache memory as described above. It
When the reading of the requested file data is completed, the controller 3 sets a flag to indicate that the file data spans a plurality of recording media (step 6). This flag is the RA in the controller 3.
It may be set to M6 or may be set to the cache memory. With that, the read process ends.

On the other hand, in step 1, when the read request from the host computer 7 is an access that does not extend over a plurality of recording media, that is, when the requested file data is recorded in one recording medium, The controller 3 controls each unit to load the corresponding recording medium (step 7) and read the requested file data (step 8). Further, the controller 3 transfers the read data to the host computer 7 and also transfers it to the hard disk 9 to store the data in the cache memory (step 8). In this case, since the file data does not span a plurality of recording media, the flag is stored without being set. With that, the read process ends.

Next, the process of storing data in the cache memory will be described with reference to FIG. In FIG. 3, first, when storing data in the cache memory,
The controller 3 judges whether or not the recording capacity of the cache memory is full, that is, whether or not there is a free area and a recording area for newly storing data can be secured (step 1). If there is no free space in the cache memory,
The controller 3 selects data to be deleted in order to store new data (step 2). When deleting the data, first, as described above, when the data is stored in the cache memory, the data in which the flag is not set, that is, the data which is not recorded across a plurality of recording media is selected as the deletion target.

When there are a plurality of data in which the flags are not set, the oldest data among them (the data that was accessed and cached before)
To be deleted. Further, when there is no data in which the flag is not set and all the data are data in which the flag is set, the oldest data among them is selected as the deletion target. When the data to be deleted is thus selected, the controller 3 erases the data area to be deleted in the cache memory to secure a recording area for new data (step 3), and stores the new data in the cache memory (step 3). 4). On the other hand, step 1
If there is an empty area in the cache memory, new data is stored in the cache memory in step 4 as it is.

As described above, in the present embodiment, when the file data is recorded over a plurality of recording media, the file data over the plurality of recording media is preferentially stored in the cache memory, so that the next time and thereafter. When a read request is issued from the host computer, the data may be transferred from the cache memory, so there is no need to load each of the plurality of recording media, and the time required to load the recording media can be saved.

In the above embodiment, when storing the file data that spans a plurality of recording media in the cache memory, it is explained that all the file data are stored, but some data may be stored. For example, only the first half data or only the second half data of the file data described in FIG. 2 may be stored in the cache memory.
In such a case, when a read request is issued from the host computer, it is necessary to read some of the data from the recording medium, but it is not necessary to load all of the recording medium. The time required to load the medium can be shortened. Further, in the embodiment, the hard disk is used as the cache memory, but the cache memory is not limited to this and may be a semiconductor memory or the like.

[0017]

As described above, according to the present invention, by preferentially storing all or part of the file data recorded on a plurality of recording media in the cache memory, When there is a read request from the host computer, there is no need to load each of the plurality of recording media, and there is an effect that the time required to load the recording media can be significantly shortened compared to the conventional case.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an information recording / reproducing system including an autochanger device of the present invention.

FIG. 2 is a flowchart showing an example of data access in the autochanger device of the present invention.

FIG. 3 is a flowchart showing an example of update processing of data in a cache memory in the auto changer device of the present invention.

[Explanation of symbols]

 1 Auto Changer Device 2 Recording Medium 3 Controller 4 CPU 5 ROM 6 RAM 7 Host Computer 9 Hard Disk (Cache Memory)

Claims (2)

[Claims] 1. A plurality of information recording media, wherein information is recorded on or reproduced from the recording medium based on an instruction from a host computer, and the plurality of recording media are recorded when viewed from the host computer. In an autochanger device that logically manages a medium as one recording medium, a cache memory for storing the data of the recording medium is provided, and when one file data is recorded over a plurality of recording media, An autochanger device characterized in that all or part of file data across a plurality of recording media is preferentially stored in the cache memory. 2. The autochanger device according to claim 1, wherein when the free area of the cache memory is exhausted, the file data that spans the plurality of recording media is preferentially stored in the cache memory. Auto changer device.