JPH04310667A - Sequential access control method of library system - Google Patents

Abstract

PURPOSE:To enable the sequential access control with short access time by removing recording medium in the sequence of housing form the housing shelf, performing the reproducing writing processing, removing next medium during the processing and waiting. CONSTITUTION:By the reproducing writing processing instruction, an accesser 4 takes out the recording medium A of a shelf 2a of a cell 1, carries them up to recording medium driving device 3, and the processing of the medium A is performed in the devices. During the processing, the accesser 4 carries next recording medium B and waits up to the processing completion of the medium A in the device 3. When the processing is completed, the medium A is takes out from the device 3, the medium B is loaded, and the processing of the medium B is performed. The processing operation is repeated, the medium housed in the cell 1 is transported sequentially to the device 3 in the predetermined order and the processing is performed. Thus, the access time can be shortened, this is added to a library system as a control program, and then, the usefulness of the library system can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sequential access control method for a library system using a predetermined recording medium such as a magnetic tape, magnetic disk, or optical disk.

0002

2. Description of the Related Art A library system includes a cell equipped with storage shelves for storing recording media, a recording medium drive device that performs playback or writing processing on the recording medium, and loading and unloading and transport of recording media to and from the cell and the recording medium drive device. It is configured as a set including an accessor (robot) that performs processing.

For example, in the case of a magnetic tape library system that uses magnetic tape as a recording medium, a cell equipped with a storage shelf for storing the magnetic tape, a tape drive device that performs playback or writing processing of the magnetic tape, and a cell and tape It consists of an accessor (robot) that takes magnetic tape in and out of the drive unit and carries it out.When the accessor receives an instruction to ``put the magnetic tape in the storage shelf number on the tape drive unit number,'' it moves the magnetic tape into the cell. The player moves to the specified storage shelf position, takes out the target magnetic tape, carries the magnetic tape to the instructed tape drive, loads it, and performs playback or writing processing.

Conversely, when a command is received to ``take out the magnetic tape from a tape drive number and store it in a storage shelf number'', the system moves to the specified tape drive and removes the loaded magnetic tape. The magnetic tape is taken out, carried to the specified storage shelf position, and stored in the original position.

[0005]

[Problems to be Solved by the Invention] By the way, when we analyze the actual business content of this type of library system, we find that most of the work is done on the host computer's DASD (Directory).
ct Access Storage Device:
This is often a backup process for data exported from direct access storage devices. This tendency is particularly strong in magnetic tape library systems that use magnetic tape as a recording medium.

[0006] In DASD backup processing, etc., the job is usually scheduled before the start of the processing, and in most cases, data is sequentially written to each recording medium according to a predetermined order. Therefore, if an access control method suitable for such sequential processing were developed in addition to the conventional random access control method, it would be more desirable for this type of library system.

The present invention has been made based on the above-mentioned circumstances, and its object is to provide a sequential access control system with a short access time and suitable for sequential processing such as backup processing.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the system of the present invention takes out a recording medium from a storage shelf in a cell using an accessor, transports it to a recording medium drive device, and plays or writes data in the recording medium drive device. In a library system in which the accessor returns the recording media to the original storage shelf after processing, the recording media are stored in the storage shelves in the cell in the order in which they are processed, and the recording media are taken out in order from the first storage shelf and processed for playback or writing. While the recording medium is being reproduced or written, the next recording medium is taken out from the storage shelf, transported to the position of the recording medium drive device, and kept on standby.

[0009]

[Operation] The principle of the present invention will be explained with reference to FIG. In the figure, 1 is a cell equipped with storage shelves 2a, 2b, . . . for storing recording media A, B, . This is an accessor (robot) that takes in and out of the recording medium into the drive device 3 and performs conveyance processing. Recording medium A,
B, . . . are sequentially stored in storage shelves 2a, 2b, .

When a host computer or the like issues a command to start playback or writing, the accessor 4 reads the first recording medium A stored in the storage shelf 2a of the cell 1.
is taken out, carried to the recording medium drive device 3, and loaded. The recording medium drive device 3 starts the reproduction or writing process for the loaded first recording medium A.

The accessor 4 is connected to the recording medium drive device 3.
While the reproduction or writing process is being performed on the first recording medium A, the process returns to cell 1 and takes out the next second recording medium B. Then, the accessor 4 takes this second recording medium B and returns to the recording medium drive device 3.
, and waits until the reproduction or writing process for the first recording medium A is completed.

[0012] When the reproduction or writing process for the first recording medium A is completed, the accessor 4 that has been waiting takes out the first recording medium A that has been processed and transfers it to the next second recording medium A.
The second recording medium B is loaded into the recording medium drive device 3. As a result, the recording medium starting device 3 starts the reproduction or writing process for the recording medium B at the second time.

When the reproduction or writing process for the second recording medium B is started, the accessor 4 transports the first recording medium A to the cell 1 during this time and returns it to the original storage shelf 2a.
Return to position.

After returning the first recording medium A to its original position, the accessor 4 moves to the storage shelf 2c where the third recording medium C is stored, and retrieves the third recording medium C. Take it out. Then, the third recording medium C is moved again to the position of the recording medium drive device 3, and waits until the reproduction or writing process of the second recording medium B is completed. The accessor 4 repeats the above processing operations, sequentially conveys the recording media A, B, .

Therefore, in the case of the present invention, while the previous recording medium is being reproduced or written, the recording medium to be processed next is taken out from the cell 1 and moved to the position of the recording medium drive device 3. When the previous recording medium is processed, the next recording medium that has been on standby is immediately supplied to the recording medium drive device 3. Compared to conventional library systems, the recording medium Access time is significantly reduced.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a first embodiment of a magnetic tape library system constructed by applying the method of the present invention. In the figure, 1 is a cell, 2a, 2b, ... are magnetic tape storage shelves, and 3
4 is a tape drive device which is a recording medium drive device, 4 is an accessor (robot), and A, B, . . . are magnetic tapes which are recording media. As the magnetic tapes A, B, . . . , for example, cartridge-type tapes that are easy to handle are used.

The cell 1, tape drive device 3, and accessor 4 described above are housed in a cabinet of a size commensurate with the system scale, and constitute one magnetic tape library system as a whole. In the figure, 7 is a host computer that instructs the magnetic tape library system to reproduce or write data.

The tape drive device 3 includes a tape drive control MPU (microprocessor) 31, a tape take-in drive circuit 32, a tape discharge drive circuit 33, and a tape drive unit 34.
The magnetic tape inserted into the tape drive circuit 3
2, the magnetic tape is transferred to and loaded into the tape drive unit 34, and the magnetic tape that has been written or reproduced is transferred to the tape ejection port 36 and ejected by the tape ejection drive circuit 33.

[0019] The accessor 4 is an MPU for accessor control.
(microprocessor), an accessor moving mechanism 42 for moving the accessor 4 between the cell 1 and the tape drive device 3, and a moving mechanism drive circuit 43 that drives the moving mechanism 42.
, a robot hand 44 for loading and unloading the magnetic tape.
, and a robot hand drive circuit 45 that drives the robot hand 44.

Next, the operation of the above embodiment will be explained using DASD backup processing as an example.

From the host computer 7, for example, the DAS
When a command for backup processing of D is sent, the tape drive control MPU 31 sends cell 1 to the accessor control MPU 41 according to a predetermined program.
A command to take out the first magnetic tape A stored in the storage shelf 2a is sent.

[0022] The accessor control MPU 41
When receiving a command to take out the magnetic tape A, the moving mechanism driving circuit 43 is controlled to start driving the accessor moving mechanism, and the accessor 4 is transferred to the position of the corresponding storage shelf 2a of the cell 1. Then, the robot hand drive circuit 45 is controlled, and the first magnetic tape A stored in the storage shelf 2a is taken out from the cell 1 by the robot hand 44.

When the accessor 4 takes out the target magnetic tape A from the cell 1, it is transported toward the tape inlet 35 of the tape drive device 3. When the robot hand 44 reaches the position of the tape inlet 35, the accessor 4
stops, and inserts the magnetic tape A held by the robot hand 44 into the tape inlet 35.

When the magnetic tape A is inserted into the tape inlet 35, the tape drive control MPU 31 controls the tape inlet drive circuit 32, and the tape inlet 35
The magnetic tape A inserted into the tape drive unit 3
4 and load it in preparation for writing data for backup processing.

[0025] Then, the tape drive control MPU 31
“READ” from the host computer 7 to indicate completion of preparation.
When the Y'' message is sent, the host computer 7 starts transmitting the backup data, and the backup data is sequentially written onto the first magnetic tape A loaded in the tape drive unit 34.

In this way, the first magnetic tape A
When the write process for cell 1 is started, the accessor control MPU 41 moves the accessor 4 toward the cell 1 again, and writes the next second cell from the storage shelf 1b in the same manner as described above.
The robot hand 44 takes out the magnetic tape B. Then, the accessor 4 that has taken out this second magnetic tape B returns to the tape inlet port 3 of the tape drive device 3.
Move to position 5 and wait at this position.

When the writing process for the first magnetic tape A is completed, the host computer 7 sends a message "UNLOAD" to the tape drive control MPU 31.
”The command is issued.

Upon receiving this "UNLOAD" command, the tape drive control MPU 31 controls the tape discharge drive circuit 33 to eject the first magnetic tape A loaded in the tape drive unit 34 and send it to the tape discharge port. Move to 36. At the same time, the accessor 4, which was waiting at the tape inlet 35,
The second magnetic tape B held by the robot hand 44 is inserted into the tape inlet 35.

The next magnetic tape B is inserted into the tape inlet 35.
When the tape drive control MPU 31 is inserted,
The tape take-in drive circuit 32 is driven in the same manner as described above, and the next magnetic tape B inserted into the tape take-in port 35 is loaded into the tape drive unit 34 in preparation for the next write process.

[0030] Then, the tape drive control MPU 31
When a tape loading completion notification is sent from the host computer 7 to the host computer 7, the host computer 7 loads the next magnetic tape B.
Transmission of write data to the magnetic tape B is started, and write processing to the magnetic tape B is started.

When the writing process on the second magnetic tape B is started, the accessor 4 uses the robot hand 44 to take out the first magnetic tape A that has been ejected to the tape outlet 36 of the tape drive device 3. .

The accessor 4, which has taken out the first magnetic tape A that has been processed as described above, returns to the cell 1.
After returning the first magnetic tape A held by the robot hand 44 to the original storage shelf 2a in the cell 1, the next third magnetic tape C is taken out. Next, the third magnetic tape C that has been taken out is conveyed again to the position of the tape inlet port 35 of the tape drive device 3, and the second magnetic tape B that is currently being processed is transported at that position.
Wait until processing is completed. The present invention is realized by repeating the above processing.

FIG. 3 shows a second embodiment of the invention. This second embodiment, contrary to the first embodiment, has a single unit on the tape drive device 3 side that also serves for inserting and ejecting the magnetic tape.
In addition to providing two tape insertion/ejection ports 38, a robot hand 44A dedicated to magnetic tape insertion is provided on the accessor 4 side.
and 2 of the robot hand 44B dedicated to taking out the magnetic tape.
Two robot hands are provided to replace magnetic tapes.

That is, the insertion robot hand 44A takes out the desired magnetic tape from the storage shelves 2a, 2b, .

When the reproduction or writing process for the previous magnetic tape is completed, the previous processed magnetic tape is ejected from the tape drive unit 34 to the tape insertion/ejection port 38 by the tape insertion/ejection drive circuit 37. .

After the ejected magnetic tape is grabbed and taken out by the ejecting robot hand 44B, the next waiting magnetic tape is grabbed by the insertion robot hand 44A and inserted into the tape insertion/ejection port 38. , the tape drive unit 3 by the tape insertion/ejection drive circuit 37.
Load into 4.

It should be noted that the processing operations other than the magnetic tape replacement are the same as in the first embodiment described above, and therefore the explanation of the other parts will be omitted.

Although the above embodiments have all been exemplified in the case of a magnetic tape library system using a magnetic tape as a recording medium, the present invention is applicable to a library system using other recording media such as a magnetic disk or an optical disk as a recording medium. It can be similarly applied to

[0039]

[Effect of the invention] As is clear from the above,
According to the present invention, it is possible to provide a sequential access control method with short access time and suitable for sequential processing such as backup processing. Therefore, if the sequential access control method of the present invention is added to the library system as one of the control programs in addition to the conventional random access control method, the optimal access control method can be selected according to the business content of the library system. As a result, the usefulness of the library system can be further improved.

Furthermore, since the next recording medium is taken out and placed on standby while the previous recording medium is being reproduced or written, the access time to each recording medium is extremely short, and the library system is Processing speed can be improved.

Furthermore, since the recording media are sequentially taken out in a predetermined order, the control commands for specifying the recording medium, address of the storage shelf, etc. are simple, and the control program can be written concisely.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a diagram showing a first embodiment of a magnetic tape library system constructed by applying the method of the present invention.

FIG. 3 is a diagram showing a second embodiment of a magnetic tape library system constructed by applying the method of the present invention.

[Explanation of symbols]

1 Cell 2a-2d Storage shelf

Claims (1)

[Claims] [Claim 1] An accessor takes out a recording medium from a storage shelf in a cell, transports it to a recording medium drive device, performs playback or writing processing on the recording medium drive device, and then returns it to the original storage shelf by the accessor. In a library system, recording media are stored in storage shelves in cells in the order in which they are processed, and the recording media are taken out in order from the first storage shelf to perform playback or writing processing, and the playback or writing processing of the recording media is performed. A sequential access control method for a library system, characterized in that the next recording medium is taken out from the storage shelf in the meantime, and transported to the position of the recording medium drive device and placed on standby.