JPS63292456A - Control system for medium assignment of plural medium containing type data recorder - Google Patents

Abstract

PURPOSE:To attain effective assignment control conforming with a processing precedence of each process by preventing a process whose processing precedence is high, from being kept waiting for a long time as to an assignment of a medium due to a process whose precedence is low. CONSTITUTION:Processes 31, 32 of processing precedences U1, U2 use a medium 13 installed to a data input/output mechanism 20, and processes 33, 34 of precedences U3, U4 use a medium 16 installed to an input/output mechanism 21. In such a case, when a process 35 of a precedence U5 requests an assignment of a medium 15 to a control means 4, the execution of the processes 33, 34 whose precedence is lower than U5 is suspended and stored temporarily in an auxiliary storage device 6, and the process 35 is executed. When the execution of the process 35 is ended and the mechanism 21 goes to idle, the processing of the processes 33, 34 is restarted. According to such a constitution, an assignment control conforming with the precedence of each process can be executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention accommodates a plurality of data recording media, and allows any data recording medium to be loaded into or removed from a data input/output mechanism by an automatic medium loading mechanism. The present invention relates to a multi-media storage type data recording device, and particularly to a control method for allocating stored data recording media to processes.

[Conventional technology]

Conventionally, when allocating a data input/output device, data recording medium, or data file to a process that is an execution unit in a computer system, the data input/output device, data recording medium, or data file requesting allocation has already been assigned to another process. If the data input/output device has been allocated to a new process, it is common to control the process to wait until the data input/output device is released from the process that was using it. Such a control method is applicable to a multi-media storage type data storage device that stores a plurality of data storage media and can load or remove any data storage medium from a data input/output mechanism using an automatic medium loading mechanism. It is also adopted when data recording media are allocated to processes using the limited data input/output mechanism.

[Problem that the invention seeks to solve]

In a multi-media storage type data storage device that uses the allocation control method described above, when the data input/output mechanism is used by another process and there is no data input/output mechanism to mount the data recording medium of the process that issued the request. , the subsequent process cannot receive the data recording medium allocation until the processing of the other processes mentioned above is completed. This type of control method can be applied when there is no distinction in the processing priority of each process, but it is suitable for systems where the processing priority of each process is different and the process with a higher priority is desired to be processed as soon as possible. In this case, a process with a high priority is forced to wait for a long time to allocate a data recording medium by a process with a low priority, making it difficult to apply the method.

Note that if the process status is displayed on a display device, etc., and the process to be executed with priority is blocked from allocating the data recording medium by another process with a lower priority, the priority It is possible for an operator to forcefully terminate other processes with low performance so that the data recording medium is promptly allocated to the process that the user wants to process with priority, but this is inconvenient and requires constant monitoring. Due to operator intervention, it is difficult to promptly allocate data storage media to processes with high processing priority, and a process that is forcibly terminated must be restarted from the beginning, resulting in a large amount of waste. Therefore, the purpose of the present invention is to assign a processing priority to each process, and automatically assign an already allocated process with a low processing priority to a process with a high processing priority. It is an object of the present invention to provide an allocation control method which allows a data recording medium to be allocated preferentially by interrupting the process, and also allows the interrupted process to be restarted from the point of interruption.

[Means for solving problems]

In order to achieve the above object, the present invention accommodates a plurality of data recording media, includes a data input/output mechanism whose number is smaller than the number of the stored data recording media, and the data input/output mechanism of any data recording medium. In a medium allocation control method for a multi-media storage type data recording device having an automatic medium loading mechanism that loads the data recording medium into the mechanism and removes the loaded data recording medium from the data input/output mechanism, the data recording medium is allocated; Allocation control means for assigning a processing priority to each process requesting release and processing requests for allocation and release of the data recording medium from the process, and storing information necessary for allocation control by the allocation control means. A management table to be managed by
auxiliary storage means for storing an interrupted state of the process, and the allocation control means is configured to send an allocation request from a process to a data recording medium that is not set in the data input/output medium when there is no free space in the data input/output medium. If the process receives a request, it determines whether the current allocation request can be executed and which data storage medium to replace, taking into consideration the results of comparing the processing priority of the process with the processing priorities of other processes currently using the data storage medium. , when it is determined that the data recording medium to be replaced is an active one, the process that is currently using the data recording medium to be replaced is interrupted, the interrupted state is stored in the auxiliary storage device, and the data recording medium to be replaced is allocated to the current allocation. Allocating a data recording medium to the process that has issued the current allocation request by replacing the data recording medium requested by the requesting process with the data recording medium requested by the requesting process, and subsequently assigning the data to the process stored in the auxiliary storage device. When the input/output mechanism becomes vacant or when a new process to be suspended is determined based on the comparison result of the processing priority of that process and the processing priority of the already allocated process, the process is retrieved from the auxiliary storage device. It has a configuration that allocates a data recording medium and restarts the process from the state immediately after the interruption.

[Effect]

All of the limited number of data input/output mechanisms are used by data recording media allocated to other processes, and there are no free data input/output mechanisms to use when allocating a data recording medium to the process that issued the current allocation request. However, if the processing priority of the process that issued the current allocation request is higher than the processing priority of the already allocated process, the allocated process is temporarily suspended and stored in the auxiliary storage by the allocation control means. Then, the automatic medium loading mechanism exchanges the data recording medium and allocates the data recording medium to the process that issued the current allocation request. Furthermore, when a space becomes available in the data input/output mechanism, the data recording medium is reallocated to the process stored in the auxiliary storage device, and the processing of that process is restarted immediately after interruption.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, which includes eight data recording media (hereinafter simply referred to as media).
11 to 18; two data input/output mechanisms 20.21. Attach any medium stored in the media storage unit IO to any data input/output mechanism 20, 21, or remove the medium installed in the data input/output mechanism 20, 21 and return it to its original location in the media storage unit 10. Media automatic loading mechanism 1 that automatically performs operations based on external instructions
A multi-media storage type data recording device l including 9 is taken as an example. As such a data recording device 1, an optical disk device that uses an optical disk as a medium, can contain a plurality of data files in one optical disk, and can allocate a plurality of processes to one optical disk is adopted. In FIG. 1, 4 is an allocation control means, 5 is a management table, 6 is an auxiliary storage device such as a magnetic disk device, and 31 to 35 are processes operating on the computer system. Each process 31 to 35 has a processing priority Ul
−U5, and the order of these priorities is U 4 < t
J 2 < U 3 < U 5 < Ul.

FIG. 2 (al~(C1 shows an example of the contents of the management table 5.

As shown in the figure, the management table 5 includes a data input/output mechanism table 201, a request process pointer 202, and a process table 203. The data input/output mechanism table 201 has the same number of data input/output mechanisms 20.21 existing in the data recording device l (therefore, in this embodiment, there are 2 data input/output mechanisms 20.21).
Each entry has the processing priority of the process with the highest processing priority among the processes to which the medium is assigned, and It consists of a pointer to the first entry in process table 203 for the process that is allocating the medium. Note that entries corresponding to data input/output mechanisms that do not have a medium installed are empty.

Requesting process pointer 202 is a pointer to an entry in process table 203 for the process requesting media allocation. If there is no process requesting media allocation, this pointer becomes an empty pointer.

The process table 203 consists of multiple entries that store various information about the process that is allocating the medium and the process that is requesting the allocation of the medium. A temporary storage flag indicating whether or not the information has been interrupted and stored in the auxiliary storage device 6, and a pointer to the entry of another process to which the same medium is allocated (
(pointer to the next process).

In addition, FIGS. 2(a) to (C1) also show the change status of the contents of the management table 5, and +a+ in FIG.
uses the medium 13 attached to the data input/output mechanism 20, and the processing priority is U3. When the processes 33 and 34 of C4 are using the medium 16 attached to the data input/output mechanism 21, the process 35 of processing priority U5 is using the medium 15.
This shows the state when a request is made to the allocation control means 4 to allocate . In addition, in the figure (bl), in the state of fa+ in the figure, there is no free data input/output mechanism, so the execution of processes 33 and 34 whose processing priority is lower than C5 is interrupted and the data is temporarily stored in the auxiliary storage device 6. After the processing is completed, the medium 15 is allocated to the process 35, and the process 35 is executing the process. This shows the state when the processes 33 and 34 resume processing according to the information stored in the auxiliary storage device 6. Allocating and releasing media to each process, suspending the process, etc. is performed by allocation control. The control means 4 is controlled by the control means 4, and the allocation control means 4 is shown in FIG.
FIG. 4 shows an example of the processing of the allocation control means 4 when the medium is released after the processing of the process using the medium is completed. Explain the operation of the example.

(Medium Allocation Process) When a medium allocation request is issued from a process, the allocation control means 4 first determines the process size, processing priority, and allocation requested medium size of the requesting process in step 301 of FIG. 3 in the process table 203. A pointer to the set entry is set in the request process pointer 202.

Next, in step 302, the data input/output mechanism table 201
An initial value ``1'' is set in a counter N for searching. Then, in step 303, it is determined whether the counter N exceeds the number of entries in the data input/output mechanism table 201. If it does, all the data input/output mechanisms 20, 21 are in use, so step 310 and subsequent steps are performed. is executed, and if there is no overage, step 304 is executed. In this step 304, it is determined whether the Nth entry in the data input/output mechanism table 201 is a free entry, that is, whether the Nth data input/output mechanism is free. If it is free, steps 305 and 306 are executed. , if it is not vacant, step 307 is executed.

If it is determined in step 305 that there is a free data input/output mechanism, the requested medium storm, the processing priority of the requesting process, and various information of the requesting process are set in the Nth entry of the data input/output mechanism table 201 in step 305. After setting the pointer to the entry in the process table 203 that has been created, the request process pointer 202 is made vacant. Then, in step 306, the requested medium is loaded into a vacant data input/output mechanism using the automatic medium loading mechanism 19 and assigned to the requesting process, and the process ends.

On the other hand, in step 304, the data input/output mechanism table 20
If the Nth entry of 1 is not a free entry,
It is determined in step 307 whether the medium installed in the data input/output mechanism is the same as the requested medium, and if it is not the same, "11" is added to the counter N in step 308, and then
Control is returned to step 303 to check the next entry in the data input/output mechanism table 201, and
If it is determined in step 307 that the attached medium and the requested medium are the same, in step 309 the pointer to the next process of the process entry pointed to at the end of the process table 203 among the processes that are allocating the medium is Set the entry in the process table 203 for the requesting process, compare the processing priority of the Nth entry in the data input/output mechanism table 201 and the processing priority of the requesting process, and select the one with the higher processing priority as the data input/output mechanism. After setting the processing priority in the Nth entry of the table 201, the requesting process pointer 202 is made vacant.

On the other hand, if the determination in step 303 is YES, that is, as a result of searching all the entries in the data input/output mechanism table 201, all the data input/output mechanisms are loaded with media used by other processes, and the media used by other processes are loaded. If the current medium is different from the requested medium (the state illustrated in FIGS. 1 and 2 corresponds to this case), the counter N is again set to the initial value °1" in step 310, and the next step 311 Then, as in step 303, it is determined whether the counter N has exceeded the number of entries in the data input/output mechanism table 201, and if it has exceeded the number, that is, the processing priority of the currently requested process is currently set as described later. If the priority is not higher than that of the process currently being processed, the requesting process's medium allocation request is assumed not to have been satisfied, and the process is terminated in order to make other processes wait for the medium to be released.As for subsequent processing, for example, the process table It is conceivable that the information of the process that issued the current request is deleted from 203, and that the process whose medium allocation request was rejected issues the request again after that.

Furthermore, if it is determined in step 311 that the number of entries in the data input/output mechanism table 201 has not been exceeded,
Execute step 312 to create data input/output mechanism table 2.
The processing priority of the Nth entry of 01 is compared with the processing priority of the requesting process, and if the processing priority of the Nth entry is lower, 1° is added to the counter N in step 313, and then the next Returns to step 311 to check the entry of the requesting process. Conversely, if the processing priority of the requesting process is higher, step 314 is executed and the medium described in the Nth entry of the data input/output mechanism table 201 is allocated. Suspend all the processes in use, temporarily store the status of each process at the time of suspension in the auxiliary storage device 6, and guarantee the processing that was being executed until the suspension,
In order to indicate that the data has been stored, the corresponding temporary storage flag in the process table 203 is set to ON, and the medium installed in the corresponding data input/output mechanism is removed by the medium automatic loading mechanism 19 as requested by the requesting process. Similarly, the medium is loaded into the data input/output mechanism by the medium automatic loading mechanism 19, and the data input/output mechanism table 2 is
The content of the Nth entry of 01 is changed to the content that matches the request process, the request process pointer 202 becomes empty, and the process ends (the state at this time is shown in Figure 2 (bl)
).

(Medium Release Process) When a medium release request is issued from a process using an allocated medium, the allocation control means 4 first sets the counter N for searching the data input/output mechanism table 201 in step 401 of FIG. Set the initial value @l”,
In the next step 402, it is determined whether the value of the counter N exceeds the number of entries in the data input/output mechanism table 201, and if it does, it is regarded as an invalid release request and an error occurs.

If the number has not exceeded the limit, it is determined in step 403 whether or not the medium attached to the data input/output mechanism indicated by the counter N is the medium for which the release request has been made. If the medium is not the medium for which the release request has been made, step After adding l'' to the counter N in step 404, control is returned to step 402 to check the next entry.6 Conversely, if the medium attached to the data input/output mechanism is the medium for which release is requested, step 405 It is determined whether the pointer to the next process entry has been set or not. If it is not set, the process that issued the release request is not stored in the process table 203, so it can be removed from an unauthorized process. An error occurs as a release request.

If it is determined in step 405 that the pointer to the next process entry has been set, the contents of the process entry indicated by the pointer are acquired in step 406, and in step 407 the process group in that process entry is set to the release requesting process. -, and if they are not equal, the control returns to step 405 to check the next process entry. If they are equal, in step 408, the entry corresponding to the process requesting the medium release in the process table 203 is determined. Make the entry free and change the pointer pointing to that entry to point to the next process entry (if there is no next process entry, set the free pointer)
.

Furthermore, in step 409, if the process that was using the medium is the one that issued the medium release request, the Nth entry in the data input/output mechanism table 201 is set to a free entry, and other processes are still using the medium. If a medium is being used, set the highest processing priority (Ud for convenience of explanation below) among the processes using the medium to the processing priority of the Nth entry in the data input/output mechanism table 201. do.

Next, in step 410, the process table 203 is searched to determine whether there is a process temporarily stored in the auxiliary storage device 6, and if there is no process, the release process is terminated. However, if there is a process that temporarily stores data in the auxiliary storage device 6 (Fig. 2 (cl corresponds to such a case)),
In step 411, the process with the highest processing priority (up for convenience of explanation) among the processes temporarily stored in the auxiliary storage device 6 is searched, and in step 412, the It is determined whether the th entry is empty or whether the processing priority tJd set in the Nth entry is lower than the highest processing priority Up among the processes temporarily stored in the auxiliary storage device 6. If the Nth entry is empty as in the case of cl in FIG. If the processing priority is lower than the processing priority Up (Ud<Up), step 413 is executed, and if it is not lower (Ud≧Up), the processing is ended.

In step 413, the medium for which the release request has been requested is removed from the data input/output mechanism by the automatic medium loading mechanism 19, the execution of the process using the medium is interrupted, and its state is temporarily stored in the auxiliary storage device 6.

In step 414, the process that was temporarily stored in the auxiliary storage device 6 and the process that was using the same medium as that process are taken out from the auxiliary storage device 6, and the medium that was being used is removed using the automatic medium loading mechanism 19. and attaches it to the data input/output mechanism, restarts the process, and completes the release process.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various other additions and changes are possible.For example, in the above embodiments, one process uses only one medium. Although an example is shown, it goes without saying that even if one process uses multiple media at the same time, it can be realized in the same way. In addition to the time, the time during which the medium was allocated to the process can also be freely added to the judgment items.

〔Effect of the invention〕

As explained above, the present invention assigns a processing priority to each process and considers the comparison result between the processing priority of the process requesting medium allocation and the processing priority of the already allocated process. This system secures a free data input/output mechanism by suspending an allocated process, and prevents a process with a high processing priority from waiting for a long time for media allocation due to a process with a low processing priority. This has the advantage that effective allocation control matching the processing priority can be automatically performed. In addition, for an interrupted process with a low processing priority, when the medium requested by that process becomes available for allocation, processing will be resumed from the state immediately after the interruption, so the process will be restarted from the beginning. It also has the effect of reducing waste.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the contents of the management table 5 and its change status, FIG. 3 is a flowchart of an example of medium allocation processing by the allocation control means 4, and FIG. is a flowchart of an example of medium release processing by the allocation control means 4. In the figure, l...Accommodates multiple media 20.21...Data recording device for outputting data Mechanism 4...Allocation control means 31-35...Process 5...Management table 201... Data output device 6...Auxiliary storage device Structure table 10...Medium storage section 202...Request process buttons 11-18...Medium (data ink recording medium) 203...Process tape 19...Medium Figure 1: Block diagram of automatic mounting mechanism

Claims (1)

[Scope of Claims] Storing a plurality of data recording media, a data input/output mechanism whose number is smaller than the number of stored data recording media, and mounting of an arbitrary data recording medium to the data input/output mechanism; In a medium allocation control method for a multi-media storage type data recording device having a medium automatic loading mechanism that removes a loaded data recording medium from the data input/output mechanism, Allocation control means for giving a processing priority to a process and processing requests for allocation and release of the data recording medium from the process; and management for storing and managing information necessary for the allocation control by the allocation control means. The allocation control means includes a table and auxiliary storage means for storing a process interruption state, and the allocation control means requests allocation to a data recording medium that is not set in the data input/output medium when the data input/output medium has no free space. is received from a process, the processing priority of the process and the processing priority of other processes that are currently using the data recording medium are taken into account to decide whether or not the current allocation request can be executed and the data recording medium to be replaced. When it is determined that the data storage medium to be replaced is executable, the process that is currently using the data recording medium to be replaced is interrupted, the interrupted state is stored in the auxiliary storage device, and the data recording medium to be replaced is replaced by the data recording medium to be replaced. Allocating a data recording medium to the process that issued the current allocation request by replacing the data recording medium requested by the current allocation requesting process with the data recording medium requested by the current allocation requesting process, and the process stored in the auxiliary storage device; Thereafter, when the data input/output mechanism becomes vacant, or when a new process to be suspended is determined based on the comparison result of the processing priority of that process and the processing priority of the already allocated process, the auxiliary storage device 1. A medium allocation control method for a multi-media storage type data recording device, characterized in that the process is restarted from the state immediately after the interruption by extracting the data from the storage medium and allocating the data recording medium.